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    • 专利摘要:
    The invention relates to an optoelectronic device for generating a frequency comb comprising a laser source (2), a ring micro-resonator (3) comprising a resonant ring (20) made of an optically non-linear three-order material. with abnormal dispersion regime. It further comprises a spectral tuning device comprising a junction guide (30) coupled to the resonant ring, electrical bias means (40) adapted to apply electrical voltage to the junction, and a control unit (42). ) adapted to change the value of the voltage to the formation of at least one dissipative time soliton in the resonant ring.
    公开号:FR3064078A1
    申请号:FR1752226
    申请日:2017-03-17
    公开日:2018-09-21
    发明作者:Corrado SCIANCALEPORE；Marco CASALE；Houssein EL DIRANI
    申请人:Commissariat a lEnergie Atomique CEA；Commissariat a lEnergie Atomique et aux Energies Alternatives CEA；
    IPC主号:
    专利说明:

    Holder (s): COMMISSIONER OF ATOMIC ENERGY AND ALTERNATIVE ENERGIES Public establishment.
    Extension request (s)
    Agent (s): INNOVATION COMPETENCE GROUP.
    OPTOELECTRONIC DEVICE FOR GENERATING A FREQUENCY COMB.
    FR 3,064,078 - A1 (5 /) The invention relates to an optoelectronic device for generating a frequency comb comprising a laser source (2), a ring micro-resonator (3) comprising a resonant ring (20) in an optically nonlinear material of order three with abnormal dispersion regime. It further comprises a spectral tuning device comprising a junction guide (30) coupled to the resonant ring, electrical bias means (40) adapted to apply an electrical voltage to the junction, and a control unit (42 ) adapted to modify the value of the electric voltage until the formation of at least one dissipative temporal soliton in the resonant ring.

    OPTOELECTRONIC DEVICE FOR GENERATING A FREQUENCY COMB
    TECHNICAL FIELD [001] The field of the invention is that of optoelectronic devices for generating a comb of quasi-coherent or coherent frequencies by the formation of dissipative temporal solitons of the Kerr type.
    PRIOR ART [002] Optoelectronic devices exist which make it possible to generate frequency combs. A frequency comb is a representation of an optical signal in the frequency domain whose spectrum is composed of a discrete sum of frequencies. The amplitude can be weighted by a spectral envelope centered around the frequency w p of a pump signal. Such optoelectronic devices find their application in particular in the field of optical telecommunications, for example networks for coherent data transmission, signal generation, fast spectroscopy, or even time reference systems.
    Figure IA illustrates an example of such an optoelectronic device 1, described in the publication of Levy et al. titled CMOS-compatible multiple-wavelength os cillât or for on-chip optical interconnects, Nature Photon. 4, 37-40 (2010), this optoelectronic device 1 being produced by microelectronics methods of the CMOS type. It includes a laser source 2 and an optical micro-resonator 3 in a ring. The laser source 2 is adapted to emit an optical signal Si n called a pump, continuous and monochromatic of wavelength λ ρ . The micro-resonator 3 comprises a coupling waveguide 10 having an input coupled to the laser source 2 and an output which provides an optical signal S or t whose spectrum forms the frequency comb generated. It further comprises an optical cavity formed by a waveguide 20 in a ring, called a resonant ring, made of a material with nonlinear optical properties of the third order, here silicon nitride SiN.
    The optical micro-resonator 3 forms an optical parametric oscillator. The pump signal Sj n , the spectrum of which is represented in FIG. 1B, couples resonantly by evanescent wave to a fundamental mode of the resonant ring 20. Insofar as the material of the resonant ring 20 is optically nonlinear of order three, that is to say that it has an electrical susceptibility of order three, a phenomenon known as of mixture with four waves in cascade appears which generates, starting from the fundamental mode supported by the ring resonant 20, a frequency comb, an example of which is shown in the figure
    IC. Furthermore, since such an optical micro-resonator 3 has a high quality factor Q, it is not necessary for the power of the pump signal to be large for the parametric gain to be greater than the optical losses present in the resonant ring 20, which makes it possible to initiate the amplification of the waves generated.
    The publication of Herr et al. titled Temporal solitons in optical m icroresonators, Nature Photon. 8, 145-152 (2014), describes another example of an optoelectronic device making it possible to generate a frequency comb by mixing with four cascaded waves, in which the resonant ring is made of a material with optical Kerr effect, more precisely in MgFî, and has an abnormal dispersion regime at the pump wavelength λ ρ . Due to the abnormal dispersion and the third order nonlinear properties of the material of the resonant ring, one or more dissipative temporal so-called Kerr solitons can be formed, which make the generated frequency comb almost coherent or coherent.
    [006] However, as Herr 2014 explains, the non-linear optical effects of the material of the resonant ring cause a shift of the Àres resonance wavelength towards the long wavelengths. In addition, the frequency scanning of the resonance shows that the latter no longer has a Lorentzian shape but of the triangular type, an example of which is shown in FIG.
    Herr 2014 shows that it is possible to form dissipative temporal solitons, which make the frequency comb generated quasi-coherent or coherent, by carrying out a sweep of the resonance by the pump frequency. Indeed, during the frequency sweep, the pump laser passes from a spectral agreement to the optical cavity in blue (blue-detuning, in English) for which the pump frequency w p is greater than the effective resonant frequency w res , to a red-detuning spectral agreement in which the pump frequency w p is less than the effective resonant frequency w res , which then results in the formation of temporal solitons. The presence of the solitons can be highlighted in particular from the value Tr of the optical transmission signal which, in the red-detuning regime, has discrete transitions as the pump frequency w p decreases, these transitions reflecting the decrease of the number of solitons propagating in the optical cavity. The frequency comb in solitonic regime also presents a greatly reduced noise, and its spectral envelope becomes of sinh 2 type when the comb is fully coherent (a single soliton in the optical cavity).
    The optoelectronic device for generating a quasi-coherent or coherent frequency comb described by Herr 2014 has the drawback, however, of having to achieve a particularly fine spectral agreement of the pump signal in resonant mode to obtain the solitonic regime Rs, which requires the use of an expensive laser source, bulky and therefore difficult to integrate.
    PRESENTATION OF THE INVENTION The aim of the invention is to remedy at least in part the drawbacks of the prior art, and more particularly to propose an optoelectronic device for generating a comb of frequencies allowing a simplified spectral agreement between the pump signal and a resonant mode in order to form dissipative temporal solitons.
    For this, the object of the invention is an optoelectronic device for generating a frequency comb comprising: a laser source adapted to emit a so-called pump optical signal, continuous and monochromatic with a wavelength constant pump over time; and an optical ring micro-resonator, comprising:
    o a so-called coupling waveguide, comprising an input optically coupled to the laser source, and an output intended to supply the frequency comb generated;
    a first ring waveguide, called a resonant ring, optically coupled to the coupling waveguide to generate an optical mode in the resonant ring at a resonant wavelength, and formed of an optically non-linear material of order three which has a refractive index and transverse dimensions such that the resonant ring has an abnormal dispersion regime associated with said optical mode.
    The optoelectronic device further comprises a spectral tuning device adapted to tune the resonance wavelength with respect to the pump wavelength to form at least one dissipative temporal soliton in the resonant ring, comprising :
    a second ring waveguide, called a junction guide, arranged opposite the resonant ring so as to be longitudinally optically coupled thereto, formed of a material whose refractive index has a deviation vis-à-vis that of the core material of the resonant ring allowing modal coupling between the two waveguides, and comprising a semiconductor junction extending parallel to the resonant ring;
    o electrical bias means adapted to apply a bias voltage of the semiconductor junction;
    a control unit, connected to the polarization means and optically coupled to the output, adapted to modify the value of the voltage to cause a modification of an effective index of the optical mode and therefore of the resonance wavelength, up to '' the formation of at least one dissipative temporal soliton in the resonant ring.
    Some preferred but non-limiting aspects of this optoelectronic device are as follows.
    The control unit can be adapted to detect an optical signal at the output, to determine a value of a parameter representative of a spectral agreement between the pump signal and an optical mode of the ring resonating at the value of the applied voltage, and inducing a modification of the value of said applied voltage until the value of said parameter reaches a reference value representative of the presence of at least one dissipative temporal soliton in the resonant ring .
    The material of the junction guide can be made of silicon.
    The material of the resonant ring can be a III-V semiconductor compound, or an element IV or a compound IV, or even a compound IV-V.
    The material of the resonant ring can be chosen from AlGaAs, GaAs, GaAsP, InGaP, InGaAsP, InGaAs.
    The resonant ring can be single-mode at the resonance wavelength.
    The difference between the refractive indices of the resonant ring and the junction guide can be less than or equal to 0.5.
    An average distance between the resonant ring and the junction guide, along an axis orthogonal to the plane along which the resonant ring extends, can be between 75nm and 200nm.
    An average width of the junction guide may be less than that of the resonant ring.
    The average width of the junction guide can be between 200nm and 500nm and that of the resonant ring can be between 400nm and 800nm.
    The materials of the resonant ring and the junction guide can be surrounded by a silicon oxide sheath.
    The invention also relates to a method for generating a frequency comb by an optoelectronic device according to any one of the preceding characteristics, comprising the following steps:
    a) emission by the laser source (2) of a monochromatic and continuous pump signal at a pump wavelength (λ ρ ) constant over time, said pump wavelength (λ ρ ) being chosen for forming an optical mode in the resonant ring (20) at the resonance wavelength (Àr es );
    b) polarization of the semiconductor junction by a non-zero voltage (U), so as to cause a change in the concentration of charge carriers within the junction guide (30), resulting in a change in the effective index of the optical mode present in the resonant ring (20) and therefore of the resonance wavelength (Àr es );
    c) detection of an optical signal at the output (12), and determination, from the detected optical signal, of a value of a parameter representative of a spectral agreement between the pump signal and the optical mode of the 'resonant ring (20);
    d) modification of the value (U) of the bias voltage, until the determined value of said representative parameter reaches a reference value representative of the presence of at least one dissipative time soliton in the resonant ring (20 ).
    At a so-called initial value of the bias voltage, the pump wavelength can be less than the resonance wavelength.
    During step d), the modification of the value of the bias voltage with respect to the initial value can cause a reduction in the resonance wavelength until it is less than the pump wavelength.
    One can determine the value of an optical transmission of the optical micro-resonator, the reference value being a minimum value of the optical transmission when the value of the bias voltage increases.
    BRIEF DESCRIPTION OF THE DRAWINGS Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of nonlimiting example, and made with reference to the accompanying drawings, in addition to FIGS. 1A-1D already described, in which:
    FIG. 1A is a schematic and partial top view of an optoelectronic device for generating a frequency comb according to an example of the prior art; FIGS. 1B and 1C respectively illustrate an example of a wavelength spectrum of the optical pump signal and an example of a frequency comb generated; and Figure ID illustrates an example of a non-Lorentzian resonance spectrum of a resonant ring made of a non-linear material of order three;
    FIG. 2A is a top view, schematic and partial, of an optoelectronic device for generating a frequency comb according to one embodiment; Figure 2B is a cross-sectional view of the resonant ring and the junction guide along the section plane A-A;
    FIGS. 3A to 3C illustrate a first step of spectral tuning in which the applied bias voltage has a so-called non-zero initial value Uinit; fig.3A being a cross-sectional view of the resonant ring and the junction guide, fig.3B a spectrum of the optical transmission signal having a spectral agreement in blue (bluedetuning), and fig.3C a comb of generated frequencies reflecting the absence of dissipative temporal solitons;
    FIGS. 4A to 4C illustrate a subsequent step of spectral tuning in which the bias voltage has a value less, in absolute value, than the initial value Uinit, for which the solitonic regime Rs is obtained; fig.4A being a cross-sectional view of the resonant ring and the junction guide, fig.4B a spectrum of the optical transmission signal having a spectral agreement in red (red-detuning), and fig.4C the frequency comb generated, this being quasi-coherent or coherent due to the presence of several or only one dissipative temporal solitons;
    FIG. 5 illustrates an example of evolution of the dispersion parameter D associated with the resonant optical mode as a function of the value of the applied voltage U of bias; and FIG. 5B illustrates an example of the value of the offset Δν in frequency of the effective resonance as a function of the value of the applied voltage U of bias.
    DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS In the figures and in the following description, the same references represent the same or similar elements. In addition, the different elements are not shown to scale so as to favor the clarity of the figures. Furthermore, the different embodiments and variants are not mutually exclusive and can be combined with one another. Unless otherwise noted, the terms "substantially", "approximately", "in the order of" mean to the nearest 10%.
    The invention relates to an optoelectronic device for generating a quasi-coherent or coherent frequency comb. It includes an optical micro-resonator which forms an optical parametric oscillator, in which a frequency comb is generated by a non-linear phenomenon of order three of mixing in four cascade waves, associated with the formation of dissipative temporal solitons of the Kerr type. . The frequency comb is said to be quasi-coherent when the frequency lines are partially in phase relation with each other, reflecting the presence of several temporal solitons. It is said to be coherent, or fully coherent, when all the frequency lines are in mutual phase relationship, which is the case when a single temporal soliton is present in the optical cavity. The operating regime of the frequency comb generator is said to be Rs solitonic when one or more temporal solitons are present.
    An optical parametric oscillator is a coherent light source which is based on a parametric amplification in an optical resonator. The optical resonator here comprises an optical cavity produced in a non-linear medium of the third order, that is to say comprising an electrical susceptibility χΆ of order three, allowing the mixture with four cascaded waves to take place, thus generating a comb of frequencies.
    The cascaded four-wave mixing is a third order non-linear phenomenon in which two photons of pump frequency w p are converted without loss of energy into a photon known as signal of frequency w s and a photon said complementary (idler, in English) of frequency w c . It is said to be cascaded insofar as the photons generated are also at the origin of the generation of other signal and complementary photons by mixing with four waves.
    The optical Kerr effect is a non-linear phenomenon of order three which expresses the dependence of the refractive index of a medium on the intensity of the optical signal which passes through it. This dependence can be formalized by the relation: n = no + n 2 .I where n is the refractive index of the material, no = (1 + χ (1) ) 1/2 is the linear refractive index, where χθ) is the electrical permittivity of order 1, n 2 is the nonlinear index which depends on the electrical permittivity χ (3) of order 3, and I is the intensity of the optical signal which crosses the medium.
    As detailed below, to allow the formation of time dissipative Kerr solitons, the optical cavity of the micro-resonator is made of a material with an optical Kerr effect, the refractive index and the opto-geometric dimensions of which are chosen to present an abnormal dispersion regime associated with the fundamental optical mode that it supports. As detailed below, the refractive index can be high, for example close to that of silicon, so that the ring waveguide has transverse dimensions such that it is then single mode.
    The dispersion is said to be abnormal when the dispersion parameter D is positive. This parameter D, expressed in ps / (nm.km), is defined as the product of a quantity β 2 and -2πο / Xæ s where Àres is the wavelength of the fundamental mode supported by the ring resonating at which is granted the pump signal, which is less than the pump wavelength λ ρ when the solitonic regime is reached. The quantity P2, also called group velocity dispersion (GVD, for Group Velocity Dispersion, in English), corresponds to the fact that the group speed of the optical signal is dependent on the wavelength of the signal. This quantity P2 is defined as being equal to the derivative of the inverse of the group speed of the optical signal: β 2 = —— where v g is the group speed of the signal
    OW Vg optical considered, w the frequency. In other words, it corresponds to the second derivative of P (w) with respect to w, to the resonant wavelength, where P (w) is the propagation constant which depends on the opto-geometric characteristics of the waveguide and of the spatial distribution of the optical field of the associated mode.
    The optoelectronic device has several waveguides. In general, each waveguide has a lower face and an opposite upper face, and rests on a support at the level of the lower face, and has lateral flanks which extend from the upper face up to on the underside. It thus presents transverse dimensions of height and width. By height is meant the average distance of the waveguide, and more precisely of the so-called core material, along the axis Z orthogonal to the plane of the support, between the lower and upper faces. By width is meant the average distance between the lateral flanks of the waveguide, and more precisely of the core material, in a plane parallel to the plane of the support. The height and the width are preferably substantially constant along the longitudinal extent of the waveguide.
    Figure 2A is a top view, schematic and partial, of an optoelectronic device 1 for generating frequency combs according to one embodiment, adapted to provide a quasi-coherent or coherent comb. This optoelectronic device 1 comprises a laser source 2 adapted to emit a continuous monochromatic optical signal, an optical micro-resonator 3 in a ring, and a spectral tuning device 4 adapted to achieve the spectral tuning of the resonant mode with the pump signal by modifying the effective index of the resonant mode supported by the micro-resonator 3, so as to obtain the solitonic regime Rs. FIG. 2B is a cross-sectional view of the resonant ring 20 and of the junction guide 30 along a plane AA illustrated in Figure 2A.
    In the following description, a three-dimensional orthogonal coordinate system (Χ, Υ, Ζ) is defined where the axes X and Y form a plane parallel to the planes along which the waveguides of the optoelectronic device rest, and where l Z axis is oriented according to the thickness dimension of the waveguides.
    The laser source 2 is adapted to emit an optical signal Si n called a pump. This optical signal is continuous and monochromatic, of wavelength λ ρ . The pump wavelength λ ρ is then substantially constant over time. It is chosen to be able to resonantly excite a fundamental mode supported by the resonant ring 20 of the optical micro-resonator 3. By way of example, it can be equal to approximately 1.55 μm in the case of a so-called telecom application, or even be equal to about 1.3 lpm for a so-called datacom application, or even also be a wavelength of the visible or of the infrared, in particular of the medium infrared.
    The pump wavelength λ ρ is provided to excite a fundamental mode of the resonant ring 20 without however that the solitonic regime is initially reached. Indeed, insofar as the resonant ring 20 is made of a material with non-linear effects of order three, the effective resonance wavelength λ ιν , is greater than the linear resonance wavelength (due to of the non-Lorentzian triangular form of the resonance spectrum), the pump wavelength λ ρ is initially less than the effective resonance wavelength Àr es , resulting in a spectral agreement in blue (blue-detuning ), as shown in Figure 3B. The transition to spectral tuning in the red (red-detuning) to address the solitonic regime Rs is carried out by the spectral tuning device 4 described below.
    Furthermore, the power of the pump signal is chosen so as to be greater than the optical losses present in the optical micro-resonator 3, so that the parametric gain is greater than the optical losses and that the amplification of the optical signal in the optical micro-resonator 3 can generate a frequency comb by mixing four waves in cascade. The laser source 2 can be transferred to the sheath layer 52 surrounding the coupling guide 10 and the resonant ring 20, or even be integrated inside this layer 52.
    The optical micro-resonator 3 in a ring includes a waveguide 10 called coupling and a first waveguide 20 in a ring, called resonant ring.
    The coupling waveguide 10 has an input 11 and an output 12, which also form the input and the output of the optical micro-resonator 3. The input 11 is optically coupled to the laser source 2 to receive the pump signal Si n emitted by the latter, and the output 12 is adapted to supply the frequency comb generated. It comprises a coupling zone 13 allowing optical coupling to the resonant ring 20 by evanescent wave.
    The coupling waveguide 10 is made of a material, called a core, with a high refractive index. More precisely, it comprises a core formed from a material with a high refractive index surrounded by a sheath 52 formed from a material with a low refractive index. The guide rests on a surface of a support layer 50 whose material participates in forming the sheath. For example, the core material of the guide 10 is preferably identical to that of the resonant ring 20, and can be chosen from semiconductor compounds III-V comprising at least one element from column III and at least one element of column V of the periodic table, or among the elements or semiconductor compounds IV or IV-V comprising at least one element of column IV. For example, III-V compounds can be, among others, AlGaAs, GaAs, InGaAs, InGaAsP, InGaP. The elements or compounds IV or IV-V can be Si, or even SiN such as S13N4. The sheath material can be, among other things, silicon oxide SiO, for example S1O2.
    The waveguide 10 extends longitudinally between the inlet 11 and the outlet 12, with a shape which can be arbitrary. By way of example, for a pump length λ ρ of 1.55 pm, the transverse dimensions of the waveguide 10 can range from a few hundred nanometers to several micrometers. The waveguide 10 can be monomode or multimode. In this example, it is preferably single mode and supports a TE type mode (electrical transverse).
    The first ring waveguide 20, called the resonant ring, forms the optical cavity of the micro-resonator 3. As with any optical parametric oscillator of the Kerr type, it comprises a non-linear material of order three making it possible to generate optical waves of wavelength different from the resonance wavelength by mixing four waves in cascade. In addition, the resonant ring 20 is dimensioned and has a refractive index so that the chromatic dispersion is abnormal for the resonant optical mode. Thus, it is possible to form one or more dissipative time solitons of the Kerr type making it possible to make the comb of frequencies generated by the mixture of four waves in cascade quasi-coherent or coherent.
    The resonant ring 20 is a ring-shaped waveguide. It has an optical coupling zone allowing it to be coupled by evanescent wave to waveguide 10. It can extend in the form of a circle, an oval or the like. In this example, it has the shape of a circle whose radius r is defined from a longitudinal line traversing the transverse barycenters of the resonant ring 20. By transverse barycenter is meant the barycenter locally associated with a cross section of the waveguide.
    The resonant ring 20 is made of a high index material with non-linear optical properties of order three. More precisely, it is made of a material called a core with a high refractive index surrounded by a sheath made of a material with a low refractive index. The core material can be chosen from III-V compounds with optical Kerr effect, or from elements or compounds IV, or IV-V, with optical Kerr effect. Preferably, the core material of the resonant ring is AlGaAs, but it can also be GaAs, InGaAs, InGaAsP, InGaP, or other effect III-V compound. Kerr optics. The elements or compounds IV or IV-V can be Si or even SiN such as S13N4. In addition, as will be specified below, the core material of the resonant ring 20 has a refractive index, more precisely a linear refractive index, close to that of the material of the junction guide 30. Furthermore, the material sheath may be, among others, silicon oxide SiO, for example S1O2. The resonant ring 20 has an upper face 21h and a lower face 21b which rests on the support layer 50, and lateral flanks 22i, 22e which extend between the upper faces 21h and lower 21b. It has a thickness e ga and a width l ga substantially constant along its longitudinal extent. It rests on the same support layer 50 as the coupling waveguide 10 so that the underside 21b of the resonant ring 20 and that of the waveguide 10 are substantially coplanar.
    The resonant ring 20 is adapted to be optically coupled to the waveguide 10. Thus, it is dimensioned so that there is phase agreement between the fundamental optical mode, here TEoo, supported by the guide wave 10 and the resonant optical mode, here TEoo, supported by the resonant ring 20. In other words, the propagation constant of the fundamental mode TEoo supported by the resonant ring 20 is equal to the propagation constant of the fundamental mode TEoo supported by the guide 10, which results here in quasi-equality or equality between the effective index of the fundamental mode TEoo supported by the resonant ring 20 with that of the fundamental mode TEoo supported by the guide 10.
    In general, the effective index n e ff associated with an optical mode supported by a waveguide is defined as the product of the propagation constant β and λ / 2π. The propagation constant β depends on the wavelength λ of the optical mode, as well as on the properties of the waveguide (refractive index and transverse dimensions). The effective index of the optical mode corresponds, in a certain way, to the index of refraction of the waveguide “seen” by the optical mode. It is usually between the index of the heart and the index of the sheath of the waveguide.
    The resonant ring 20 is further adapted to provide parametric conversion of frequencies by mixing four waves in cascade. For this, the material of the resonant ring 20, that is to say its so-called core material, has nonlinear optical properties allowing the optical Kerr effect, and thus has a refractive index which depends on the intensity of the optical signal passing through it. Four-wave mixing by optical Kerr effect is then possible.
    The resonant ring 20 is more suitable for forming one or more dissipative time solitons known as Kerr. By definition, a soliton is a solitary optical wave which propagates without deformation in a non-linear and dissipative medium. These solitons are said to be of the Kerr type insofar as they are generated in a non-linear material of the third order by the optical Kerr effect. Insofar as the solitonic regime can only appear in an optical cavity where the dispersion is abnormal, the resonant ring 20 is adapted so that the dispersion is abnormal for the resonant mode, here TEoo, supported by the resonant ring 20 For this, as shown in the publication by Okawachi et al entitled Octavespanning frequency comb generation in a Silicon nitride chip, Opt. Lett. 36, 3398 (2011), taking into account the refractive index, that is to say here the linear index, of the material of the resonant ring 20, the transverse dimensions of height e ar and / or of width l ar of the resonant ring 20 are chosen so that the latter has an abnormal dispersion regime associated with the fundamental mode, here TEoo · In the case where the core material is a III-V material with an optical Kerr effect, such as AlGaAs, whose refractive index is higher, here of the order of 3.4 to 1.55 μm approximately, the chromatic dispersion is abnormal for dimensions of thickness and / or width of l resonant ring 20 such that the guide remains single mode.
    For example, in the case of a pump wavelength λ ρ equal to approximately 1.55 pm, and for a material of the core of the resonant ring 20 made of AlGaAs, the height e ga is preferably between 300nm and 500nm, and the width l ga is preferably between 400nm and 800nm. Thus, the optical mode supported by the resonant ring 20 has an abnormal dispersion regime. These transverse dimensions make the ring resonant not multimode but rather monomode, which thus makes it possible to rule out the disturbances likely to degrade the formation of temporal solitons due to interference between optical modes, as described in the publication by Kordts et al. . titled High order mode suppression in high-Q anomalous dispersion SiN microresonators for temporal dissipative Kerr soliton formation, Opt. Lett. 41, 452 (2016).
    The spectral tuning device 4 is adapted to modify the resonance wavelength λ ιν , from the optical mode supported by the resonant ring 20 relative to the pump wavelength λ ρ kept substantially constant in time, until reaching the solitonic regime Rs in the resonant ring 20. For this, it comprises a waveguide 30 with a semiconductor junction, electrical polarization means 40 of the semiconductor junction, and a control unit 42 adapted to modify the value of the electrical polarization applied to the junction.
    The junction waveguide 30 is a second ring waveguide of the optoelectronic device 1. It is positioned vertically on the resonant ring 20, along the Z axis, so that it extends in a plane parallel to the plane of the resonant ring 20. It extends along a longitudinal axis parallel to that of the resonant ring 20, and thus has a longitudinal shape substantially identical to that of the resonant ring. The resonant ring 20 and the junction guide 30 are therefore superimposed on each other.
    The junction guide 30 has a lower face 31b and an opposite upper face 31h, the upper face 31h being oriented towards the lower face 21b of the resonant ring 20. The height c gJ of the junction guide 30 is the distance average between its lower 31b and upper 31h faces. The width lgj of the guide is the average distance between its lateral flanks 32i, 32e. The height and the width are substantially constant along the longitudinal extent of the junction guide 30. It rests on a substrate 51 which participates in forming the sheath of the junction guide 30 with the support layer 50.
    Internal lateral parts 33i and external 33e extend radially from the junction guide 30. The guide 30 associated with the lateral parts 33i and 33e thus forms a ribbed waveguide (rih waveguide, in English). Thus, an internal lateral part 33i extends from the circumference of the internal lateral flank 32i in the direction of the center of the ring 30, and an external lateral part 33e extends from the circumference of the external lateral flank 32e, towards the outside of the ring 30. The internal lateral parts 33i and external 33e are made of the same material as that of the junction guide 30, and are each doped according to an opposite type of conductivity. Thus, the internal lateral part 33i can be doped with type N and the external lateral part 33e can be doped with type P, or vice versa. The lateral parts 33i, 33e each rest on the substrate 51, but have a local height less than the height e ^ of the junction guide 30, so as to avoid spreading at the level of the lateral parts 33i, 33e of the optical supermode present in the junction guide 30 and the resonant ring 20. As an example, the height e g i of the guide 30 can be approximately 300nm and the height of the lateral parts 33i, 33e can be approximately 150nm, or even less, for example 50nm.
    Furthermore, internal lateral parts 33i and external 33e are in contact with circumferential portions 34i, 34e overdoped. The internal overdoped portions 34i and external 34e are made of the same material as the lateral parts 33i, 33e and each have the same type of conductivity as the lateral part 33i, 33e with which it is in contact. However, they have a higher dopant density than that of the corresponding side part 33i, 33e. More specifically, the internal overdoped portion 34i, resp. external 34e, is in contact with the internal lateral part 33i, resp. external 33e, and has a higher doping level than the latter. These overdoped portions 34i, 34e make it possible to reduce the series resistance between the polarization electrodes 41i, 41e and the junction guide 30.
    Finally, an internal bias electrode 4li is in contact with the internal lateral part 33i, here by the internal overdoped portion 34i, and an external polarization electrode
    41e is in contact with the external lateral part 33e, here by the external overdoped portion 34e. Each polarization electrode 4 li, 41e comprises an electrically conductive material which fills a trench produced in the sheath material 52 of the resonant ring 20 and in the support layer 50, which opens on the upper face of the internal overdoped portion 34i or external 34th. Thus, a difference in electrical potential, or bias voltage U, can be applied to the semiconductor junction of the junction guide 30 by the electrodes 4li, 41e, via the lateral parts 33i, 33e and here overdoped portions 34i, 34th.
    The junction guide 30 thus comprises a semiconductor junction which extends along the longitudinal axis of the waveguide, substantially parallel to the resonant ring 20. The semiconductor junction is of PN or PIN type, or even is a capacitive junction, and is formed of an N-type doped area and of a P-type doped area. In this example, the semiconductor junction is of PN type in the sense that the N and P-doped areas are in contact one from the other, without being separated from each other by an intrinsic zone (ie not intentionally doped) or by a dielectric zone. Thus, purely by way of illustration, the internal portion 34i can here be N + doped, the internal lateral part 33i doped N, the external lateral part 33e doped P, and the external portion 34th overdoped P +. The zone 35i doped N of the junction guide 30 is in electrical continuity with the internal lateral part 33i doped N, and the zone 35e doped P is in electrical continuity with the external lateral part 33e doped P. A space charge zone ( ZCE) is formed at the interface between the N and P doped areas of the junction guide 30, whose width 1 Z ce depends on the applied bias voltage U. The modification of the concentration of the carriers in the junction guide 30 during the polarization of the junction can be carried out by depletion of carriers during a reverse polarization, or by injection of carriers, or even by accumulation of carriers in the case of 'a capacitive junction. Classic examples of semiconductor junctions whose properties are modified by depletion, injection or accumulation of carriers are given in particular in the publication by Reed et al. titled Silicon optical modulators, Nature photonics 4, 518-526 (2010).
    The semiconductor junction, in the absence of polarization, is preferably located substantially in the center of the junction guide 30. The optical properties of the junction guide 30 are intended to be modified, in particular the effective index associated with the mode optical, by an adequate polarization of the semiconductor junction, in order to modify the wavelength of the resonance λ ιν , of the optical mode of the resonant ring 20.
    For this, the junction guide 30 has optical and geometric characteristics, as well as a positioning with respect to the resonant ring 20, advantageously chosen so as to allow good modal coupling between the two guides d on the one hand, and to maintain an abnormal dispersion regime associated with the optical mode in the resonant ring 20 on the other hand.
    By modal coupling, it is meant that the optical mode circulating in the resonant ring 20 extends spatially both in the resonant ring 20 and at least partly in the junction guide 30, then forming a supermode. More specifically, the component of the electric field of the optical supermode has a spatial distribution which covers the resonant ring 20 as well as at least part of the junction guide 30. Thus, by the modal coupling between the two waveguides, the modification of the refractive index of the junction guide 30 will induce a modification of the effective index of the supermode and therefore a variation of the resonance wavelength À es , while preserving the abnormal dispersion regime of the supermode in the resonant ring 20. These properties, associated with the fact that the resonant ring 20 is made of a material with an optical Kerr effect, make it possible to achieve a spectral agreement of the resonance with the pump signal to obtain a solitonic regime.
    Modal coupling between the resonant ring 20 and the junction guide 30 is ensured by their relative positioning on the one hand, and by the choice of their core materials on the other hand. The vertical spacing d between the junction guide 30 and the resonant ring 20, namely the distance between the upper face 31h and the lower face 21b, is between a first value d m i n to preserve the abnormal dispersion in the resonant ring 20 and a second value d max greater than d m i n to allow modal coupling. By way of illustration, in particular in the case of a resonant ring 20 made of AlGaAs and of a junction guide 30 made of silicon, the distance d is between 75 nm and 200 nm. In addition, the core materials of the resonant ring 20 and of the junction guide 30 are chosen close to one another so as to allow the spatial spreading of the optical mode circulating in the resonant ring 20 at the level of the junction guide 30. More precisely, the refractive indices n ar and of the core materials have a deviation less than or equal to 0.5, so that I n ar -n ^ l <0.5. The refractive indices here correspond to the linear optical indices of the materials considered. Preferably, the junction guide 30 is made of silicon, whose refractive index is equal to 3.48 at the wavelength of 1.55 pm, and the resonant ring 20 is made of AlGaAs whose index of refraction is equal to 3.44 for an aluminum concentration of approximately 20%. The refractive index is here the linear term of the refractive index. The junction guide 30 can be made of a material identical to that of the resonant ring or of a different material. The material of the junction guide 30 is preferably silicon, but may be SiN, such as S13N4, or AlGaAs, GaAs, InGaAs, InGaAsP, InGaP, or the like. It can also be chosen from chalcogenides.
    Furthermore, the junction guide 30 has transverse dimensions, in particular in width lgj, chosen so that the dispersion regime remains abnormal in the resonant ring 20, so that the variation of the concentration of charge carriers in the junction guide 30 can impact the resonance wavelength λ, -es of the supermode in the resonant ring 20. The width lgj of the junction guide 30 is thus between a first width l m i n in order to be able to modify the resonance wavelength λ ιν , and a second width l max greater than l m i n to preserve the abnormal dispersion in the resonant ring 20, this width l max being less than that of the resonant ring 20. As Illustrative, for a resonant ring 20 of AlGaAs with a width of between 400nm and 800nm and a junction guide 30 of silicon, the width lgj is between 200nm and 500nm, while always being less than the width l ar of the ann resonant water 20.
    The spectral tuning device 4 comprises electrical polarization means 40 of the semiconductor junction, adapted to apply a difference in electrical potential to the junction in order to induce a change in the concentration of charge carriers within of the junction guide 30, thus causing a change in the effective index of the supermode. In this example, the semiconductor junction is reverse biased so as to induce a depletion of the carriers in the junction guide 30. For this, the biasing means 40 comprise a voltage source, the value of the electric voltage U applied to the semiconductor junction is intended to be modified. The voltage source 40 is connected to the polarization electrodes 41e, 4 li, thus making it possible to polarize the P and N doped zones of the junction by means of the internal lateral parts 33i and external 33e.
    The spectral tuning device 4 comprises a control unit 42, connected to the electrical polarization means 40, and optically coupled to the output 12 of the coupling guide 10, and adapted to modify the value U of the applied electrical voltage at the semiconductor junction until the solitonic regime is reached, that is to say until one or more dissipative temporal solitons are present in the resonant ring 20.
    Preferably, the control unit 42 comprises at least one optical sensor and a computer. The optical sensor is optically coupled to output 12 to receive a detection signal corresponding to at least part of an optical output signal, and to determine a value of a parameter associated with the detected optical signal which is representative of the agreement. spectral between the pump signal and the optical mode of the resonant ring 20, for the value U of the applied bias voltage. The computer compares the measured value to a reference value representative of the presence of at least one dissipative time soliton in the resonant ring 20. The control unit 42 is then able to modify the value of the bias voltage U until the determined value reaches the reference value, thus translating the obtaining of the solitonic regime.
    For example, the parameter representative of the spectral agreement can be the value of the transmission rate determined from the detected optical signal. The optical transmission rate of the optical micro-resonator 3 corresponds to the ratio of the intensity of the optical output signal to the intensity of the optical input signal. As the publication of Herr 2014 indicates, the transmission rate Tr decreases as the difference between the resonance wavelength λ ιν , and the pump wavelength λ ρ decreases, with Àr es > À p , which characterizes the blue-detuning regime. Then, from a minimum value Tr re f of optical transmission which can then correspond to the reference value, the optical transmission Tr increases suddenly in a discrete manner, that is to say in stages, as the difference between the resonant wavelength Ares and the pump wavelength λ ρ increases, with λπ ^ λρ, the pump wavelength λ ρ remaining substantially constant. The solitonic regime is then obtained. For this, the control unit 4 may include a photodiode optically coupled to the output 12, an oscilloscope, and a processor provided with a memory.
    As a variant or in addition, obtaining the solitonic regime can be detected from the analysis of the noise associated with a radiofrequency (RF) signal translating interference between lines of frequencies close to the comb generated, or even from of the change of sign of a PDH signal (for Pound-Drever-Hall, in English) as a function of the voltage V of bias applied.
    The operation of the optoelectronic device 1 according to the embodiment is now described, with reference to Figures 3A-3C and 4A-4C. In this example, the junction guide 30 is made of silicon and the resonant ring 20 of AlGaAs. The semiconductor junction is reverse biased so that the modification of the effective index of the optical mode supported by the resonant ring 20 and the junction guide 30 is obtained by modification of the region of depletion of the carriers in the junction.
    The laser source 2 emits an optical signal Si n of a continuous and monochromatic pump of wavelength λ ρ , a spectrum of which is illustrated in FIG. 1B. The pump wavelength λ ρ therefore remains substantially constant over time. In addition, the bias voltage U applied in reverse to the semiconductor junction has a so-called non-zero initial value Uinit for which the junction has a width of space charge area called initial lzcE.init greater than the width of charge area of equilibrium space Izce.o for which the applied voltage is zero.
    The pump signal Si n is transmitted by the coupling waveguide 10 towards the output 12. Insofar as the waveguide 10 is single-mode in this example, the pump signal corresponds to a fundamental mode of the guide 10, for example TEoo By optical coupling of evanescent type between the first waveguide 10 and the resonant ring 20, the pump signal Si n resonantly excites a fundamental mode of the ring resonant 20, here the TEoo mode - More precisely, the optical coupling is achieved by the phase agreement between the fundamental mode TEoo of the first guide 10 and the fundamental mode TEoo of the resonant ring 20. Thus, a large part or the almost all of the optical signal Si n is transmitted from the coupling guide 10 into the resonant ring 20.
    The optical mode traversing the resonant ring 20 spreads spatially so as to cover, by modal coupling, both the resonant ring 20 and the junction guide 30 superimposed on each other, and forms thus a supermode. Modal coupling is possible due to the value of the distance d vertically separating the resonant ring 20 and the junction guide 30 on the one hand, and by the small difference between the refractive index n ar of the ring resonant 20 and the refractive index ngj of the junction guide 30, preferably such that ln ar ngjl = 1 Anl <0.5, on the other hand. The effective index n e ff associated with the supermode thus depends on the refractive indices n ar and n ^ and on the geometric dimensions of the waveguides 20, 30. Insofar as the refractive index n ^ depends on the voltage of polarization U, the effective index n e ff also depends on the polarization voltage U.
    The supermode has an effective resonant wavelength Ares, which is of non-Lorentzian triangular shape due to the non-linear optical properties of order three of the material of the resonant ring 20. By definition, the length of Resonance wave Very to the order m is defined by the relation: 2πΐΊΚ · η = ηιÀr es , m , here in the case where the resonant ring 20 forms a circle of radius r, n e ff being the effective index of supermode. The resonance wavelength λ ιν is greater than the so-called linear resonance wavelength λι; η for the same order m, this corresponding to the case where the material of the resonant ring 20 is optically linear. Insofar as the effective index n e ff depends on the bias voltage U, the resonance wavelength λ ιν , also depends on the bias voltage U.
    Preferably, the pump wavelength λ ρ has been chosen to be less than the effective resonance wavelength λ ιν , at the voltage Uo, and may have been chosen close to, or even equal to, the linear resonance wavelength λϋ η . Also, as illustrated in FIG. 3B, the pump signal and the resonant mode initially present, for Uinit, a spectral agreement in blue (blue-detuning, in English). The pump signal however excites a resonant mode of the resonant ring 20, which makes it possible to generate a comb of frequencies by mixing in four waves in cascade, the comb however not being coherent insofar as the solitonic regime Rs n 'is not reached, as shown in Figure 3C.
    The spectral tuning device 4 then operates a decrease in the resonant wavelength Ares vis-à-vis the pump wavelength λ ρ which remains substantially constant, by applying a continuous decrease, in absolute value, from the bias voltage U at the semiconductor junction, until the formation of one or more dissipative time solitons in the resonant ring 20.
    In this example, the formation of dissipative time solitons is detected from the change in the value of the transmission rate Tr of the optoelectronic device 1. Using a detection waveguide 43, all or part of the output signal is received and then transmitted to a photodiode which supplies the intensity of the detected optical signal. An oscilloscope records the value of the intensity of the detected signal as a function of the value of the bias voltage U. This results in a signal of the transmission rate Tr as a function of the bias voltage U. Thus, for the initial voltage applied Uinit, we obtain an initial Trinit transmission rate.
    In this example, the spectral tuning device 4 applies a bias voltage U in reverse to the semiconductor junction, whose U value, between the initial value and the equilibrium value Uo, gradually decreases in absolute value . This results in a reduction in the width Izce of the space charge zone (FIG. 4A), which translates a progressive increase in the concentration of the carriers in the semiconductor junction. The refractive index ngj (U) of the junction guide 30 is modified, which here leads to a reduction in the effective index n e ff (U) associated with the supermode, and therefore a reduction in the resonance wavelength Ar es (U). The oscilloscope records the decrease in the transmission rate Tr (U) as the voltage U decreases in absolute value, which indicates that the spectral agreement between the pump signal and the resonant mode remains in blue (blue-detuning ).
    However, from a value U less than or equal to a reference value U re f, in absolute value, the effective resonance wavelength ^ (U ^ Uref) becomes less than the wavelength of pump λ ρ , that is to say that the spectral agreement is in the red (reddetuning), as illustrated in figure 4B. The oscilloscope then detects an increase in stages of the transmission rate Tr (U), a sign that the solitonic regime is reached. The formation of dissipative temporal solitons is indeed effective when the spectral agreement is in the red, insofar as the dispersion regime remains abnormal despite the presence of the junction guide 30. As described above, the dimensioning of the junction guide 30 , in particular its width lgj relative to that of the resonant ring 20, and the value of the distance d make it possible to keep the dispersion of the supermode abnormal.
    When the solitonic regime is reached, the spectral tuning device 4 stops the decrease in the bias voltage U. The voltage value is then between the reference value U re f and the equilibrium value Uo . However, the number of solitons present in the resonant ring 20 can be controlled as a function of the value U of the applied bias voltage. More specifically, the stepwise increase in the transmission rate reflects the decrease in the number of solitons present in the resonant ring 20. It is also possible to detect the full coherence of the frequency comb by comparing the spectral envelope of the frequency comb generated with respect to the sinh 2 function (Figure 4C).
    Thus, at output 12 of waveguide 10, a coherent frequency comb is obtained. It presents a constant free spectral interval, that is to say a constant value of spacing between the successive frequency lines, as well as a low noise of frequency and / or amplitude. In addition, when a single dissipative temporal soliton traverses the resonant ring, the amplitude of the frequency lines is weighted by a spectral envelope of the hyperbolic sine type squared (sinh 2 ) centered on the pump wavelength λ ρ , thus reflecting the consistency of the frequency comb.
    The optoelectronic device 1 is thus able to achieve a spectral agreement between the pump signal and the resonant mode exhibiting in the optical micro-resonator 3 in order to reach the solitonic regime Rs, and thus generate a quasi-coherent or coherent frequency comb . Unlike the example of the prior art mentioned above, the spectral tuning device 4 does not include a tunable laser which is able to carry out a sufficiently fine and precise scanning of the resonance. Such a tunable laser has the disadvantages of not being able to be integrated simply at the level of the support substrate and can be bulky. It may also not be precise enough, which can result in difficulty in addressing the solitonic regime. Indeed, as shown in Figure 1D, the solitonic regime exists only for over a narrow width of the resonance spectrum.
    On the contrary, the spectral tuning is ensured by keeping the pump wavelength λ ρ substantially constant and by using a junction guide positioned opposite the resonant ring 30 to allow the formation of a supermode, the effective index of which is modified by the polarization of the semiconductor junction. The modification of the effective index, and therefore of the resonance wavelength λ ιν , of the supermode, makes it possible to pass from blue-detuning to red-detuning, a necessary condition for the formation of dissipative temporal solitons. Thus, the spectral tuning is simplified, fast and precise, via a spectral tuning device easily integrated into a substrate, in particular of the SOI type.
    Furthermore, when the resonant ring 20 is made of an III-V material with an optical Kerr effect and the junction guide 30 is made of silicon, the resonant ring 20 has an abnormal dispersion regime for transverse dimensions d thickness and width such that it remains single mode. This makes it possible to avoid the presence of several optical modes in the resonant ring 20, the possible interference of which is liable to degrade the formation of dissipative time solitons of the Kerr type.
    Purely by way of illustration, the optoelectronic device 1 may include a laser source 2 adapted to emit an optical signal from a monochromatic pump (continuous), of a wavelength substantially constant over time, for example equal to 1.55pm. . The pump signal is guided in the coupling waveguide 10, the latter being single-mode and supporting the fundamental mode TEoo · The resonant ring 20 is made of AlGaAs which is a Kerr-effect III-V material optics with a high non-linear index value m. Thus, the optical power necessary for the generation of a frequency comb by mixing with four cascaded waves is low, less than 10 mW, and remains less than the two-photon absorption optical power of the silicon forming the junction guide 30. it is based on a 50 silicon oxide support layer SiO x, e.g. S1O2, and has a shape of circle of radius r about 12,5pm, e g a thickness of 400nm and a width approximately the ga 630nm. The resonant ring 20 is therefore single mode at 1.55pm and here supports the TEoo fundamental mode · The resonant ring 20 has a chromatic dispersion parameter D associated with the TEoo fundamental mode at 1.55pm equal to 764.2 ps / (nm .km) in the absence of junction guide 30. The resonant ring 20 is surrounded by a sheath produced here in silicon oxide SiCU.
    Furthermore, the junction guide 30 is made of Si. It is superimposed on the resonant ring 20 in the direction -Z, and has a shape of a circle with a radius of 12.5 μm also. The junction guide 30 has a thickness egj of approximately 300 nm and the width lgj is approximately 280 nm. The distance d separating the junction guide 30 from the resonant ring 20 is approximately lOOnm. Thus, the dispersion of the supermode remains very abnormal despite the presence of the junction guide 30, thus authorizing the formation of dissipative temporal solitons.
    In this example, the semiconductor junction is reverse biased, thus causing controlled depletion of the carriers in the space charge area. More precisely, the ZCE has an initial width lzcE.init to Uinit which decreases with the decrease in the value U of the bias voltage (in absolute value). In addition, the initial voltage Uinit applied is chosen to fully deplete the junction guide 30, so that lzcE, init ~ lgj, thus making it possible to increase the spectral shift of the resonance Δλ ιν , =
    Xr es (Uo = O) - Àres (U), and thus facilitate the spectral agreement in red between the pump signal and the resonant mode, while remaining below the breakdown voltage so as not to damage the semiconductor junction. In this example, the doping density of acceptors and donors in the side inner parts 33i and 33e are external to N: = Nd = l, l7 25.10 cnr [0090] As illustrated in FIG 5A, the value of the parameter chromatic dispersion D of the optical mode in the resonant ring 20 depends on the bias voltage U applied to the semiconductor junction. Thus, in this example, the parameter D varies between a value of 24 ps / (nm.km) at zero equilibrium voltage Uo, and a value of 50 ps / (nm.km) at an initial voltage Uinit of -2 , 8V approx. It remains positive regardless of the value of the voltage U between Uinit and Uo, thus reflecting the fact that the dispersion remains abnormal during the spectral tuning phase for obtaining the solitonic regime. Thus, the presence of the junction guide 30 and the application of the bias voltage do not disturb the formation of dissipative time solitons in the resonant ring 20.
    FIG. 5B illustrates an example of evolution of the value of the offset Av res in frequency of the resonance as a function of the bias voltage U. The frequency shift Av res of the resonance is defined as the difference between the resonance frequency w res (Uo) at zero voltage Uo and the resonance frequency w res (U) at non-zero voltage: Av res (U) = w res (U) - w res (Uo). In this example, the semiconductor junction is reverse biased, which leads to depletion of the carriers. Thus, the frequency shift Δν is here of the order of 550 MHz when the bias voltage U reaches a value of approximately -2.8V.
    Particular embodiments have just been described. Different variants and modifications will appear to those skilled in the art.
    Thus, the resonant mode present in the resonant ring 20 mentioned above is the TE mode (electrical transverse) but it could be the TM mode (magnetic transverse). In this case, the quality factor of the resonant ring 20 can be higher insofar as the supermode TM perceives only the roughness of the lower and upper faces of the waveguides since it oscillates along the Z axis and not in the XY plane. However, the lower and upper faces of the waveguides have a roughness less, at least of an order of magnitude, than that of the lateral flanks.
    权利要求:
    Claims (15)
    [1" id="c-fr-0001]
    1. Optoelectronic device (1) for generating a frequency comb, comprising: o a laser source (2) adapted to emit a so-called continuous, monochromatic optical pump signal with a pump wavelength (λ ρ ) constant over time; o an optical micro-resonator (3) in a ring, comprising:
    a waveguide (10) called coupling, comprising an input (11) optically coupled to the laser source (2), and an output (12) intended to supply the frequency comb generated;
    a first ring waveguide (20), called a resonant ring, optically coupled to the coupling waveguide (10) to generate an optical mode in the resonant ring (20) at a resonant wavelength ( X res ), and formed of an optically nonlinear material of order three which has a refractive index (n ar ) and transverse dimensions (l ar , e ar ) such that the resonant ring (20) has a regime of abnormal dispersion associated with said optical mode;
    characterized in that it further comprises:
    a spectral tuning device (4) adapted to tune the resonance wavelength (Ares) relative to the pump wavelength (λρ) to form at least one dissipative temporal soliton in the resonant ring, including:
    a second ring waveguide (30), called a junction guide, arranged opposite the resonant ring (20) so as to be longitudinally optically coupled to the latter, formed of a material whose index of refraction (n ^) has a deviation from that (n ar ) of the core material of the resonant ring allowing modal coupling between the two waveguides (20, 30), and comprising a junction semiconductor extending parallel to the resonant ring (20);
    electrical bias means (40) adapted to apply a bias voltage (U) to the semiconductor junction;
    a control unit (42), connected to the biasing means (40) and optically coupled to the output (12), adapted to modify the value of the voltage (U) to cause a modification of an effective index of the optical mode and therefore from the resonance wavelength (Ares), until the formation of at least one dissipative temporal soliton in the resonant ring (20).
    [2" id="c-fr-0002]
    2. Device (1) according to claim 1, wherein the control unit (42) is adapted to detect an optical signal at the output (12), to determine a value of a parameter representative of a spectral agreement between the pump signal and an optical mode of the resonant ring (20) at the value of the applied voltage (U), and to induce a modification of the value of said applied voltage (U) until the value said parameter reaches a reference value representative of the presence of at least one dissipative temporal soliton in the resonant ring (20).
    [3" id="c-fr-0003]
    3. Device (1) according to claim 1 or 2, wherein the material of the junction guide (30) is silicon.
    [4" id="c-fr-0004]
    4. Device (1) according to any one of claims 1 to 3, wherein the material of the resonant ring (20) is a III-V semiconductor compound, or an element IV or a compound IV.
    [5" id="c-fr-0005]
    5. Device (1) according to any one of claims 1 to 4, in which the material of the resonant ring (20) is chosen from AlGaAs, GaAs, GaAsP, InGaP, InGaAsP, InGaAs.
    [6" id="c-fr-0006]
    6. Device (1) according to any one of claims 1 to 5, wherein the resonant ring (20) is single-mode at the resonant wavelength (Ares).
    [7" id="c-fr-0007]
    7. Device (1) according to any one of claims 1 to 6, in which the difference between the refractive indices (n ar , n ^) of the resonant ring (20) and of the junction guide (30) is less than or equal to 0.5.
    [8" id="c-fr-0008]
    8. Device (1) according to any one of claims 1 to 7, in which an average distance (d) separating the resonant ring (20) and the junction guide (30), along an axis orthogonal to the plane along which extends the resonant ring (20), is between 75nm and 200nm.
    [9" id="c-fr-0009]
    9. Device (1) according to any one of claims 1 to 8, in which an average width (lgj) of the junction guide (30) is less than that (l ar ) of the resonant ring (20).
    [10" id="c-fr-0010]
    10. Device (1) according to claim 9, wherein the average width (lgj) of the junction guide (30) is between 200nm and 500nm and that (l ar ) of the resonant ring (20) is between 400nm and 800nm.
    [11" id="c-fr-0011]
    11. Device (1) according to any one of claims 1 to 10, in which the materials of the resonant ring (20) and of the junction guide (30) are surrounded by a sheath of silicon oxide.
    [12" id="c-fr-0012]
    12. Method for generating a frequency comb by an optoelectronic device (1) according to any one of the preceding claims, comprising the following steps:
    a) emission by the laser source (2) of a monochromatic and continuous pump signal at a pump wavelength (λρ) constant over time, said pump wavelength (λρ) being chosen to form a optical mode in the resonant ring (20) at the resonance wavelength (Ar es );
    b) polarization of the semiconductor junction by a non-zero voltage (U), so as to cause a change in the concentration of charge carriers within the junction guide (30), resulting in a change in the effective index of the optical mode present in the resonant ring (20) and therefore of the resonance wavelength (λ Γε5 );
    c) detection of an optical signal at the output (12), and determination, from the detected optical signal, of a value of a parameter representative of a spectral agreement between the pump signal and the optical mode of the 'resonant ring (20);
    d) modification of the value (U) of the bias voltage, until the determined value of said representative parameter reaches a reference value representative of the presence of at least one dissipative time soliton in the resonant ring (20 ).
    [13" id="c-fr-0013]
    13. Method according to the preceding claim, wherein, at a so-called initial value (Uinit) of the bias voltage (U), the pump wavelength (λρ) is less than the resonance wavelength (Ares ).
    [14" id="c-fr-0014]
    14. Method according to the preceding claim, in which, during step d), the modification of the value (U) of the bias voltage with respect to the initial value (Uinit) results in a decrease in the wavelength resonance (Ares) until it is less than the pump wavelength (λρ).
    [15" id="c-fr-0015]
    15. Method according to any one of claims 12 to 14, in which the value of an optical transmission of the optical micro-resonator (3) is determined, the reference value being a minimum value of the optical transmission when the value ( U) of the bias voltage increases.
    1/5
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20160011489A1|2013-02-28|2016-01-14|Ecole Polytechnique Federale De Lausanne |Generating optical pulses via a soliton state of an optical microresonator|
    US8519803B2|2010-10-29|2013-08-27|Hewlett-Packard Development Company, L.P.|Resonator systems and methods for tuning resonator systems|
    US9195113B2|2012-05-25|2015-11-24|Honeywell International Inc.|Tunable multispectral laser source|
    WO2015012915A2|2013-04-22|2015-01-29|Cornell University|Parametric comb generation via nonlinear wave mixing in high-q optical resonator coupled to built-in laser resonator|
    WO2018081824A1|2016-10-31|2018-05-03|The Regents Of The University Of California|Adiabatic dispersion-managed frequency comb generation|
    FR3061776B1|2017-01-09|2019-05-31|Commissariat A L'energie Atomique Et Aux Energies Alternatives|OPTOELECTRONIC DEVICE FOR GENERATING A COMBINED FREQUENCY COMB|FR3061776B1|2017-01-09|2019-05-31|Commissariat A L'energie Atomique Et Aux Energies Alternatives|OPTOELECTRONIC DEVICE FOR GENERATING A COMBINED FREQUENCY COMB|
    DE102017200755B3|2017-01-18|2018-03-08|Leoni Kabel Gmbh|Sensor line, measuring arrangement and method for detecting an environment variable|
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    DE112019005104T5|2018-10-12|2021-10-07|Imra America, Inc.|COMPACT MICRORESONATOR FREQUENCY COMB|
    FR3090909B1|2018-12-20|2021-05-07|St Microelectronics Crolles 2 Sas|Ring resonator electro-optic device|
    US11221540B2|2019-09-17|2022-01-11|Government Of The United States Of America, As Represented By The Secretary Of Commerce|Optical parametric oscillator and producing idler coherent light and signal coherent light from pump coherent light|
    US11226537B2|2020-02-06|2022-01-18|Palo Alto Research Center Incorporated|Multi-layer optical device exhibiting anomalous dispersion|
    CN111969396B|2020-07-27|2021-07-27|中国科学院西安光学精密机械研究所|High-integration intermediate infrared broadband super-continuum spectrum generation device and method|
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    优先权:
    申请号 | 申请日 | 专利标题
    FR1752226A|FR3064078B1|2017-03-17|2017-03-17|OPTOELECTRONIC DEVICE FOR GENERATING A FREQUENCY COMB|
    FR1752226|2017-03-17|FR1752226A| FR3064078B1|2017-03-17|2017-03-17|OPTOELECTRONIC DEVICE FOR GENERATING A FREQUENCY COMB|
    EP18161911.5A| EP3385784A1|2017-03-17|2018-03-15|Optoelectronic device for generating a frequency comb|
    US15/923,571| US10268100B2|2017-03-17|2018-03-16|Optoelectronic device for generation a frequency comb|
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