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    • 专利摘要:
    Optical device, method and system for remote detection of optical network terminals. Device, method and system for the detection of user optical terminal equipment (for example ONTs) of a client fiber optic distribution network that allows detecting, from the optical terminal box (CTO), remotely if there is a terminal equipment in the user's home optically connected, whether or not it is turned on. That is, the proposed solution allows, remotely and independent of the transmission system used, to detect and identify from the operator's optical terminal box, which fiber optic connections (connections) actually end in an optical rosette at the customer's home that has an optically connected ONT, whether or not it is electrically powered. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2827373A1
    申请号:ES201931016
    申请日:2019-11-20
    公开日:2021-05-20
    发明作者:Anton Sergio Prieto；Garcia Manuel Toca
    申请人:Telefonica SA；
    IPC主号:
    专利说明:

    [0002] Optical device, method and system for remote detection of optical network terminals
    [0004] Object of the invention
    [0006] The present invention has application in the technical sector of optical fiber telecommunications and, in particular, it presents a technical solution for the detection of optical network terminals, also called optical network terminals (ONTs, from English Optical Network Terminals).
    [0008] Background of the invention
    [0010] Fiber optic data distribution networks are increasingly used to provide broadband data connections to users. This is how passive optical networks (PON) have appeared, which allow the distribution of data through fiber optics. The fiber network is called differently depending on where the PON network ends, so we would have for example: fiber to the building (FTTB, Fiber To The Building) or fiber to the home (FTTH, Fiber To The Home). The latter allow communication via fiber optics with optical network terminals (ONTs) or optical network units (ONUs, Optical Network Unit) located at the user's home (or generally speaking in the place where the user has their equipment of optical network connection) or near it.
    [0012] In fiber optic access networks to the home (FTTH), the telecommunications operator systems that provide fiber optic service deploy their own fiber network and take it to the optical terminal boxes (CTOs) installed on the facades or in the Inside the buildings, which provide shelter for the elements necessary to divide the existing resources between the connected clients (users).
    [0014] It is common for FTTH fiber optic deployments to be carried out in phases or spans. In a first phase, the deployment is carried out from the operator's central head office (where the OLT optical line terminal is located, from the English Optical Line Terminal, which controls the distribution of operator signals through optical fiber) to the optical terminal box (CTO). In this first phase, those real estate units from which FTTH service could be provided from said CTO are considered in coverage or "past home". In environments where there are several operators with their own networks deployed in parallel, this phase is designed with a specific penetration percentage, foreseeing that the clients will be distributed among the different operators.
    [0016] In a second phase, already at the time of registration of a real estate unit, the last section of fiber optic (fiber optic connection) is laid from the CTO to the interior of the client's home, ending at a termination point of the Optical Network (PTRO) and from there to the ONT Network Optical Terminal. The PTRO (rosette) can be considered to be the termination point of the passive part of the FTTH optical network that is installed at the customer's home (normally it is present in a home if there has ever been a fiber registration in the address, whether there is a client with a service currently contracted or not). Through a fiber optic cord (usually with SC / APC connectors) the PTRO is connected to the ONT optical terminal, which is the active user equipment that communicates with the headend (OLT) to provide the customer's contracted service. This last section of the network, which goes from the optical terminal box (CTO) to the optical rosette (PTRO), installed inside the customer's home, is capable of being shared by different operators.
    [0018] In figure 1, an example architecture of an FTTH optical network deployment is shown where there is a first level optical splitter (101) to which the optical signal of the OLT located in the central headend arrives and distributes the optical signal to the different optical terminal boxes (CTOs, 102), which would incorporate the second level dividers. The deployment that would correspond to the first phase would reach this point. In the second phase, the fiber deployment is carried out between the CTOs and the optical rosettes (PTROs, 103) and from there to the end user's ONTs (104) that will deliver the signal (already converted to an electrical signal) to the user equipment for their consumption. As seen in the figure, each CTO has several ports (8 in figure 1 although this is only an example and can have any other number of ports) which allows it to connect to several user terminals having a fiber optic connection ( fiber optic connection) between each port of the CTO and each user terminal (the maximum number of terminals to which it can be connected will be equal to the number of ports that the CTO has).
    [0020] Due to the aforementioned characteristics of FTTH network deployments, in some cases the fiber optic connections may not be disconnected from the CTO when the customer drops the service or changes operator and, therefore, a mismatch may occur between what is physically installed and what is registered in the operator's systems (between the installed optical connections and the actually active users of that operator). That is, there may be one or more fiber optic connections occupying ports in the CTO box without actually those connections being connected to user terminals or ONTs, that is, without actually providing service to any user (client) of the operator. . For example, in a real situation, you can have an optical terminal box (CTO) with all its ports occupied by fiber optic connections, although in reality, in some cases, there is no longer a client connected, for example, because it has changed operator and the new operator has decided to lay a new connection without disconnecting the connection previously installed by the first operator.
    [0022] These circumstances oblige operators to repeatedly check, in situ and physically, if the inventory registered in their systems corresponds to what is actually installed on the network. These checks can be done more or less quickly and reliably, checking the identification and labeling of the customer connections, and if they were not labeled (because the labels have disappeared) disconnecting the connections from each client and checking if the ONT that would correspond to it remains active or not. This can be done as long as all the ONTs with active service are synchronized at the time of the check, and it could make it possible to identify which fiber optic connections are not connected to an active client and which ones are.
    [0024] However, it often happens that, for example, during periods of absence at home, the customer disconnects the ONT from the power supply and this loses synchronism with the operator's headend (with the OLT). In these cases, it is impossible, with current methods, to identify fiber optic connections without an active client.
    [0026] For this reason, there is a need for an optical ONT remote sensing device that solves this problem by being able to detect, from the operator's optical terminal box, which fiber optic connections (connections) actually end in an optical rosette in the customer address that has an ONT optically and physically connected, whether or not it is turned on and synchronized.
    [0027] In the state of the art there are proposals to detect and identify ONTs, but not to detect active ONTs like the present invention. Thus, in some patents of the state of the art, solutions are presented to solve problems related to problematic ONTs, which for one reason or another transmit in instants of time that do not correspond to them, interfering with the optical signals of other ONTs and causing the system to works incorrectly (such as US7468958 B2 or US2007 / 0242954 A1 or US2008 / 0138064 patent applications). In other cases, it is a matter of introducing additional equipment in the ports of the OLTs that provides the functionality of detection of reflections in the fiber optic network to detect possible failures or breaks in the network and determine the distance at which the problem occurs. has produced (such as US2005 / 0201761).
    [0029] However, in all the above cases, the problem to be solved is not that of detecting active ONTs, whether or not they are electrically powered, and the element in which the detection device is to be added is in the transmission equipment placed in the central, the OLT. In the embodiments proposed in the present text, on the contrary, the equipment to be used would be independent of the transmission system and the test point in which it could be used would be different, specifically in the last section of the FTTH network from the CTO to the customer address, where the ONT should be connected. Furthermore, unlike the cited state of the art, the objective is to detect from the optical terminal box if there is an ONT, connected or not, at the opposite end of an optical drop cable, regardless of whether the ONT is on or off in that moment.
    [0031] Description of the invention
    [0033] The present invention serves to solve the problems mentioned above, by means of a device and method of Remote Detection of client / user optical terminal equipment (for example ONTs, ONUs) that allows to detect from the optical terminal box (CTO) and remotely if there is a physically connected customer terminal equipment (at the customer's home) whether or not the terminal equipment is switched on.
    [0035] In other words, the proposed solution allows, remotely and independent of the transmission system used, to detect and identify from the operator's optical terminal box, which fiber optic connections (connections) actually end in an optical rosette at the customer's home. that an ONT is optically connected, whether or not it is electrically powered, and which ones are not. This allows the operator to really know which connections are associated with active clients and which are not, being able to disconnect unused connections (freeing up the corresponding ports), thus efficiently using the resources of the distribution network and, specifically, the resources. of optical terminal boxes CTOs.
    [0037] Specifically, in a first aspect, a method is presented to detect the presence of a user's optical network terminal equipment (normally located at the user's home) optically connected to a fiber optic connection of a fiber optic distribution network, where the method comprises the following steps:
    [0039] a) Transmit an optical device connected to the fiber optic connection, a first optical signal of a certain wavelength with a first polarization, through the fiber optic connection;
    [0040] b) Measure the optical device, the optical power of the first reflected optical signal received through the fiber optic connection (that is, of the optical signal received through the fiber connection as a result of the reflection of the first signal optics);
    [0041] c) Transmitting the optical device, through the fiber optic connection, a second optical signal of the determined wavelength with a second polarization different from the first polarization;
    [0042] d) Measure the optical device, the optical power of the second reflected optical signal received through the fiber optic connection (that is, of the optical signal received through the fiber connection as a result of the reflection of the second signal optics);
    [0043] e) Compare the difference between the optical power measured in step b) and step d) with a threshold value and determine the presence of the user optical network terminal equipment based on the result of said comparison.
    [0045] Step e) may comprise: if said difference is greater than the threshold value, determining that there is a user optical network terminal equipment optically connected to the fiber optic connection, and otherwise, determining that there is no optical network terminal equipment user connected optically to the fiber optic connection.
    [0047] In one embodiment, it comprises a step prior to a), which consists of:
    [0048] - disconnect the fiber optic connection from an optical terminal box, CTO, and connect the fiber optic connection to the device.
    [0049] Step e) can be performed in a processor of the device and the result of the determination is communicated by means of a message over a communication network and / or is presented by means of a user interface of the device.
    [0051] The optical powers measured in steps b) and d) can be communicated by means of a message through a communication network and / or presented by means of a user interface of the device.
    [0053] In one embodiment, the first polarization is the polarization where the measured power of the reflected signal is maximum and the second polarization is the polarization where the received signal of the reflected signal is minimum. For example, prior to step a), an optical signal with a certain initial polarization is transmitted and, starting from that initial polarization, the polarization of the transmitted signal is modified until reaching the polarization where the reflected signal has a maximum power, first polarization, (step a)) and the polarization of the transmitted signal is modified until reaching the polarization where the reflected signal has a minimum power, second polarization (step c)).
    [0055] The fiber optic distribution network can be a passive optical network, PON.
    [0057] The optical network termination terminal equipment may be an ONT.
    [0059] In one embodiment, the wavelength of the optical signal emitted in steps a) and c) is close to that of the transceiver of an ONT in a passive optical network, for example 1310 nm.
    [0061] In one embodiment, the device is connected to a switch connected in turn to a group of several fiber optic connections, and where the switch consecutively connects the device with each of the fiber optic connections of the group and steps a) - e) are made for each of the group's fiber optic connections.
    [0063] In a second aspect, devices are presented to carry out any of the methods described above. Specifically, a device detector device for user optical network terminal equipment of a fiber optic distribution network is presented, where the device comprises:
    [0064] - An optical source emitting an optical signal at a certain wavelength;
    [0065] - A polarization controller of the optical signal;
    [0066] - An optical circulator that comprises three optical ports and is configured to transmit all the optical signal received by the first port (P1) to the second port (P2) of the circulator and to transmit all the optical signal received by the second port (P2) to the third port (P3); or an optical coupler configured to transmit a first percentage of the power of a signal received by a first input / output port towards a common port and to transmit a second percentage of the signal received by the common port towards a third input / output port. exit.
    [0067] - An optical meter connected to the third port of the circulator or optical coupler.
    [0069] The output of the device is connected to a fiber optic drop. Additionally, the device may comprise a processor configured to cause the following actions to be performed:
    [0070] - Establishing a first polarization by the polarization controller and transmitting a first optical signal at the certain wavelength, emitted by the optical source, with the first polarization through the fiber optic connection;
    [0071] - Measure in the optical meter the optical power of the first reflected optical signal, received through the fiber optic connection and the coupler or the optical circulator;
    [0072] - Establishing a second polarization by the polarization controller and transmitting a second optical signal at the certain wavelength, emitted by the optical source, with the second polarization through the fiber optic connection;
    [0073] - Measure in the optical meter the optical power of the second reflected optical signal, received through the fiber optic connection and the coupler or the optical circulator.
    [0075] In a third aspect, a system is presented to detect the presence of a user optical network terminal equipment, optically connected to a fiber optic connection of a fiber optic distribution network, where the system comprises a device as described above, at least one fiber optic drop and at least one optic terminal box, CTO.
    [0077] Finally, in another aspect of the invention a computer program is presented that comprises computer-executable instructions to implement the described method, when executed on a computer (or a digital signal processor, an application-specific integrated circuit, a microprocessor , a microcontroller or any other way programmable hardware). Said instructions may be stored on a digital data storage medium.
    [0079] The scope of the present invention is defined by the appended independent and dependent claims. For a more complete understanding of the invention, its objects and advantages, reference may be made to the following specification and the accompanying drawings.
    [0081] Brief description of the figures
    [0083] Next, a series of drawings will be described very briefly that help to better understand the invention and that expressly relate to an embodiment of said invention that is presented as a non-limiting example thereof.
    [0085] FIGURE 1.- Shows a schematic block diagram of an FTTH fiber optic access network deployment.
    [0087] FIGURE 2.- Shows a schematic block diagram of the last phase of an FTTH fiber optic access network deployment in which the ONT detection device is used, according to an embodiment of the invention.
    [0089] FIGURE 3.- Shows a view of a transceiver used in an ONT or ONU of a passive fiber optic network (PON).
    [0091] FIGURES 4a and 4b.- They show two schematic block diagrams of an ONT detector device, in the initial state and after modifying the polarization, according to an embodiment of the invention.
    [0093] FIGURE 5.- Shows a schematic block diagram of an ONT detector device according to an embodiment of the invention.
    [0095] FIGURE 6.- Shows a schematic block diagram of an ONT detector device according to an embodiment of the invention.
    [0096] Detailed description of the invention
    [0098] Examples of embodiments of the invention are described in detail below, making reference when necessary to the figures cited above, without limiting or reducing the scope of protection of the present invention.
    [0100] In the embodiments described below, devices and methods for remote detection of fiber optic termination user terminal equipment (for example, ONTs, ONUs) that allow detection in the last section of the network (specifically from the box) will be presented. CTO optical terminal) if there is a physically connected user terminal equipment (at the customer's home), whether or not it is turned on. This text will normally refer to the detection of ONTs in FTTH networks but the solution proposed in the present invention can be used for any type of fiber optic termination user terminal (ONT, ONU or any other type) and for any type fiber optic signal distribution network.
    [0102] In figure 2, an example of the architecture of the last section of an optical FTTH network is shown in which the ONT detection device can be used, according to an embodiment of the invention. As seen in the figure, the optical device (equipment) for remote detection of ONTs (201) would be connected to the different optical connections (205), preferably at the point where the connections are connected to the CTOs (202). To do this, it is necessary to disconnect the connections to be tested from the different ports of the CTO, and connect them to the remote detection device for ONTs. In figure 2, only one detector device is shown, but of course several devices (201) each can be used simultaneously to test a connection to make detection faster or, as we will see later, even a multi-port device that allows testing more of a rush.
    [0104] From that point (outside plant), the device will detect whether an optical network terminal equipment is connected (for example, an ONT (204)) or not (in turn connected to a PTRO (203 )), regardless of whether it is on or off. This detection will be based on the mechanism explained below:
    [0106] An ONU or ONT (and in general, any optical network user terminal equipment) designed for PON networks (with point-multipoint architecture), has a optical transceiver, which allows it to receive (downstream) the optical signal at a given wavelength from the OLT (located in the operator's central head-end), and in turn allows it to transmit the optical signal at a different wavelength to the upward direction, through a single optical fiber. An example of said electro-optical or transceiver element (known from the state of the art) of an ONT is shown in figure 3. This element, by allowing the use of the same optical fiber to allow communication in both directions (in different lengths of waves) is also known as Bidirectional Optical Sub-structure or BOSA (Bi-directional Optical Sub-Assembly).
    [0108] Said optical transceiver converts, by means of a photodetector (301), the optical signal from the OLT into an electrical signal and, on the other hand, by means of an optical transmitter (for example, a laser diode (302)) converts the electrical signal generated by the ONT, into an optical signal that is sent to the OLT.
    [0110] In the case of an FTTH network using current GPON (Gigabit-capable Passive Optical Network) technology, the wavelength used for the downstream (OLT ^ ONT) is 1490 nm, and the wavelength used for the upstream direction (ONT ^ OLT) is 1310 nm (this is just a non-limiting example and other wavelengths can be used for the upstream and downstream directions).
    [0112] Both optical signals are transmitted through a single optical fiber (303) so lenses (304) are necessary, to orient and confine the light beams, and some coupler / multiplexer element that allows combining the optical signals of the ascending directions. and downstream, from the laser diode to the optical fiber (upstream) and from the optical fiber to the photodetector (downstream). Thus, for example, there will be a light beam splitter (305) that will allow the existence of these two optical paths: from the laser diode to the optical fiber (306), and from the optical fiber to the photodetector (307).
    [0114] These transceivers produce a high reflection (2) when, from the optical fiber, they receive an incident optical signal (1) with a wavelength close to that of the laser diode emission, that is to say that used in the upward direction (1310 nm in example above). Additionally, this reflection (2) is strongly affected by the type of polarization of the light beam of this incident signal (1). They also occur reflections in the different passive elements of a fiber optic access network, such as connectors, splitters, splice fusions, fiber optic, etc. however, these reflections are practically insensitive to changes in polarization of the incident light beam.
    [0116] Therefore, in the electro-optical element or transceiver of the ONT (BOSA) a high reflection sensitive to the polarization of the light beam occurs at wavelengths close to that emitted by its transmitter. However, the rest of the passive network behaves practically insensitive to these polarization changes. Taking advantage of this circumstance, from the fiber optic terminal box, with a detector device that directly accesses the fiber optic connection (last section of the optical network) it could be detected if there is an active equipment with an electro-optical element (transceiver) in its inside. This last section of the network between CTO and PTRO (and from there to the ONT if there is one) can only consist of an optical connection (a direct cable) from the CTO to the customer's home (as shown in figure 2 ), general case in outdoor installations or with several cable runs in indoor installations. In indoor installations there may be a section with riser-type cable (vertical of the building, or structured vertical) between the CTO and junction boxes (DC) and a final connection section from the DCs to the PTRO inside the home customers (DCs are usually placed in registers on the landings of different floors of the buildings).
    [0118] Figures 4a and 4b show in a schematic way with blocks, the elements that make up the detector device according to one embodiment of the invention (this is only an exemplary embodiment and in other embodiments, as will be shown later, the arrangement of the elements may be different). Thus, in this embodiment, the detector device for user fiber optic network terminal equipment (ONTs) would be composed of:
    [0120] - Optical source (401). Optical source of laser or led type (or any other type). Preferably, said optical source will emit a signal at the wavelength close to the emission of the laser diode of the ONT transceiver (BOSA).
    [0121] Optionally, in the event that the optical source has excessive power that could damage the optical components that make up the ONT, signal attenuators could be additionally used at the output of the optical source.
    [0122] - Polarization Controller (402). This element makes it possible to vary the polarization of the light beam from the optical source. In the embodiment shown in Figures 4a and 4b, said polarization controller will be at the output of the optical source, although other locations are possible.
    [0124] - Optical circulator (403). Optical element with three input / output ports that routes the optical signal from one input port to the adjacent output port in a single direction. That is, the signal is transmitted from port 1 (P1) to port 2 (P2), from port 2 (P2) to port 3 (P3), and from port 3 (P3) to port 1 (P1). The optical circulator must be insensitive to polarization. In the embodiment shown in Figures 4a and 4b, said circulator directs the signal received by port 1 (P1) from the optical source (after passing through the polarization controller), towards port 2 (P2), connected with the fiber optic connection from the user's home (to the ONT, if any), and the reflected signal from the ONT, (which enters the circulator through port 2 (P2)), towards the optical detector connected to the port 3 (P3) of the same.
    [0126] Optionally, instead of using an optical circulator, an optical coupler could be used. This optical coupler would have a common port and two input / output ports. One of the input / output ports transmits a percentage of the signal power to or from the common port, and the other input / output port transmits another percentage to or from the common port. In a possible embodiment, the coupler will direct the signal received from the optical source (after passing said signal through the controller), delivering it to the fiber optic connection associated with the home of a certain client (to the ONT if there is one) and will direct the reflected signal from the ONT to the optical detector.
    [0128] - Optical detector (404), also called optical meter. It measures, at the wavelength of the optical source, the optical power of the signal received through the fiber optic connection (reflected by the optical transceiver that incorporates the ONT (405) if an ONT is connected). The optical detector must be insensitive to polarization; since if it were sensitive to polarization, the power measured by it could vary when the polarization changes, without this being motivated by the existence of an ONT at the customer's home, thus distorting the ideal operation of the device (which will be explained below). continuation).
    [0129] The operation of the device is based on varying the polarization of the light beam coming from the optical source (401) and measuring the power of the reflected signal (by the electro-optical element of the ONT if there is one). A circulator (403) is used to route the optical signal from the source to the customer's home and the reflected signal (in the electro-optical element of the ONT if there is one) to the detector (404). In this embodiment, port 1 is connected to the optical source (after passing through the polarization controller), port 2 is connected to the fiber optic connection that goes to the home of the client under analysis, and port 3 is connected to the optical detector.
    [0131] As explained above, the power of the signal reflected by an optical element of an ONT is strongly affected by the type of polarization of the light beam of the incident signal. Therefore, if the optical signal transmitted by the connection reaches an ONT, the signal reflected by it will vary significantly depending on the type of polarization of the optical signal that affects the ONT. Thus, with this device, the existence of an optically connected ONT can be detected at the customer's home if a significant variation is observed in the optical meter, above a certain threshold, in the power of the reflected optical signal when the power is varied. polarization of the signal from the optical source. If the power of the reflected optical signal does not vary with polarization changes (or does so below the threshold), it could be determined that there is no ONT connected.
    [0133] The threshold value in a preferred embodiment would be around 3dB (although of course other values can be used for this threshold).
    [0135] That is, an optical signal with a certain polarization (first polarization) is emitted (figure 4a) and in the optical detector (404) a reflected signal with an optical power A is measured. The polarization is changed (to a second polarization, figure 4b) and in the optical meter (404) a reflected signal with an optical power B is measured.
    [0137] In one embodiment, this would be done as follows: Initially, the system emits an optical signal with a certain initial polarization (a priori, this can be uncontrolled). Starting from this initial polarization, and modifying the polarization of the signal by means of the polarization controller, until a determined polarization (polarization A) a situation will be reached in which the optical detector (404) will measure a reflected signal with a maximum value, power A. This situation is shown in figure 4a. Changing the polarization, up to a certain polarization (polarization B) a situation will be reached in which the optical detector (404) will measure a reflected signal with a minimum value, power B. This situation is shown in figure 4B. That is, a sweep would be made so that the maximum and minimum value of the power of the reflected signal can be detected.
    [0139] Then if, in absolute value, Received power B - Received power A> = Threshold ^ It is determined that there is ONT connected and if, in absolute value, Received power B - Received power A <Threshold ^ It is determined that there is no ONT connected (already that there is no significant change in the power of the reflected signal when changing the polarization).
    [0141] In one embodiment, the device indicates to the operator (via a user interface) the received optical power in each case (with each polarization). In another embodiment, the device itself may have a processor that performs this calculation and communicates to the operator (through a user interface that may consist of text, lights, sound ...) if it has been determined that there is an optically connected ONT or not. The device can also send a message (via a telecommunication network, for example a mobile telephone network) the power information and / or the determination made.
    [0143] Changing the polarization of the light can be commanded by the operator (via a user interface or any command that allows him to operate the polarization controller). Also in one embodiment, the device may have an automatic mode in which the device automatically changes polarization. Or in other words, the device automatically establishes a polarization and measures the power of the reflected signal, and after a time interval, it changes the polarization and measures the power of the reflected signal.
    [0145] In other embodiments, the elements of the device may be located differently. Thus, in an alternative embodiment (shown in figure 5), the location of the polarization controller (502) is changed, placing it behind port 2 of the circulator (503) instead of just at the exit of the optical source (501) (In general, it can be said that the key is that the controller is located in such a way that it can modify the polarization of the signal that affects the possible ONT). In this way, the device will behave in the same way and will detect if there is an ONT (505) connected optically or not, from the optical power measurements made by the optical meter (504).
    [0146] In other embodiments, an optical coupler can be used instead of a circulated one.For example, in the configurations shown in Figures 4a, 4b and 5, the device would have the same structure only that where the coupler is located, a coupler would be placed whose common port would be the one that delivers / receives the signal to / from the ONT (that is, the common port would correspond to port 2 (P2) of the circulator). As noted above, the coupler has one common port and two input / output ports, with each port transmitting a percentage of the common port signal. This coupler can be balanced (each port transmits 50% of the common port signal) or unbalanced (each port transmits a different percentage of the common port signal). In order to protect the optics of the ONT from receiving a high-power signal that could damage it, it is preferable to use an unbalanced coupler, for example, 90/10 or 95/5 (or any other value) , so that the incident signal on the ONT is attenuated, affecting the signal reflected by the ONT as little as possible.
    [0148] For example, in a 90/10 coupler that consists of an optical element with a common port, a port that transmits or receives 10% of the signal from the common port, and a port that transmits or receives 90%. Connecting to the output of the light source (or the polarization controller) the port with the lowest percentage (in this case 10%) would protect the ONT from possible damage due to high power; the port with the highest percentage (in this case 90%) is connected to the detector / meter to minimize the attenuation of the reflected signal and the common port is the one that would be connected to the optical connection to the customer's home. Thus, in this example, the optical signal transmitted by the optical source would go 10% towards the fiber optic connection (common port) and therefore towards the ONT (if any). The rest of the power is lost. The signal reflected by the ONT re-enters the system through the common port of the coupler directing 90% of the signal to the optical detector.
    [0150] In one embodiment, a switch (1xN) can be used to connect the device to several (N) lines. For example, to all the connections of a certain CTO. In figure 6 a device with this switch is shown schematically.
    [0152] The device would still consist of an optical source (601), a polarization controller (602), a coupler (603), and an optical detector (604). In the example of figure 6, the switch (606) would be connected to port 2 of the circulator and in turn the switch would be connected to N fiber optic connections (in other embodiments of the device, such as the one shown in Figure 5, the switch would be connected between the bias controller and the optical connections or between the circulator and the bias controller).
    [0154] The operation would be analogous to that explained for the case of a single connection, except that the device, automatically or manually, would switch between the different ports (connections) of the switch and, for each of them, the polarization would vary to determine the existence or ONT no. (605) (in the same way as explained above for the case of a single commit). With this switch, the operator would save having to pass the connection device in connection with each CTO, with the consequent saving of time and labor.
    [0156] In this text, the word "comprises" and its variants (such as "understanding", etc.) should not be interpreted in an exclusive way, that is, they do not exclude the possibility that what is described includes other elements, steps, etc. Likewise, in the claims, the expression "comprising / comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. No reference symbol in the claims should be construed as limiting the scope. .
    [0158] The specific design of each element and component shown in the figures is for illustrative and exemplary purposes only; In no case is it intended to limit the design of each component only to that shown in said figures.
    [0160] Aspects defined in this detailed description are provided to aid in a thorough understanding of the invention. Accordingly, those skilled in the art will recognize that variations, changes, and modifications can be made to the embodiments described herein without departing from the scope of the invention. Also, the description of well-known features and items are omitted for clarity and conciseness.
    [0162] Having sufficiently described the nature of the invention, as well as the way in which it is carried out in practice, it should be noted the possibility that its different parts may be manufactured in a variety of materials, sizes and shapes, and may also be introduced in its constitution or procedure, those variations that practice advises, as long as they do not alter the fundamental principle of the present invention.
    权利要求:
    Claims (28)
    [1]
    1. Method to detect the presence of a user optical network terminal equipment optically connected to a fiber optic connection of a fiber optic distribution network, where the method comprises the following steps:
    a) Transmitting an optical device (201) connected to the fiber optic connection, a first optical signal of a certain wavelength with a first polarization, through the fiber optic connection;
    b) Measure the optical device (201), the optical power of the first reflected optical signal received through the fiber optic connection;
    c) Transmitting the optical device (201), through the fiber optic connection, a second optical signal of the determined wavelength with a second polarization different from the first polarization;
    d) Measure the optical device (201), the optical power of the second reflected optical signal received through the fiber optic connection;
    e) Compare the difference between the optical power measured in step b) and step d) with a threshold value and determine the presence of the user optical network terminal equipment based on the result of said comparison.
    [2]
    2. Method according to claim 1 wherein step e) comprises: if said difference is greater than the threshold value, determining that there is a user optical network terminal equipment optically connected to the fiber optic connection and otherwise, determining that there is no user optical network terminal equipment optically connected to the fiber optic drop.
    [3]
    3. Method according to any of the preceding claims, wherein the method comprises a step prior to a), consisting of:
    - disconnecting the fiber optic connection from an optical terminal box, CTO, (202) and connecting the fiber optic connection to the device (201).
    [4]
    4. Method according to any of the preceding claims where step e) is performed in a processor of the device (201) and the result of the determination is communicated by means of a message through a communication network and / or is presented by means of an interface user name of the device (201).
    [5]
    Method according to any of the preceding claims, where the optical powers measured in steps b) and d) are communicated by means of a message through a communication network and / or presented by means of a user interface of the device (201).
    [6]
    6. Method according to any of the preceding claims where the first polarization is the polarization where the measured power of the reflected signal is maximum and the second polarization is the polarization where the received signal of the reflected signal is minimum.
    [7]
    7. Method according to any of the preceding claims where, prior to step a), an optical signal with a certain initial polarization is transmitted and, starting from that initial polarization, the polarization of the transmitted signal is modified until reaching the polarization where the reflected signal it has a maximum power, first polarization, and the polarization of the transmitted signal is modified until reaching the polarization where the reflected signal has a minimum power, second polarization.
    [8]
    8. Method according to any of the preceding claims, wherein the fiber optic distribution network is a passive optical network, PON.
    [9]
    A method according to any one of the preceding claims, wherein the user optical network terminal equipment is an ONT.
    [10]
    10. Method according to any of the preceding claims, wherein the wavelength of the optical signal emitted in steps a) and c) is close to that of the transceiver of an ONT in a passive optical network.
    [11]
    Method according to any one of the preceding claims, wherein the wavelength of the optical signal emitted in steps a) and c) is 1310 nm.
    [12]
    Method according to any of the preceding claims, where the device (201) is connected to a switch (606) connected in turn to a group of several fiber optic connections, and where the switch (606) consecutively connects the device with each of the group's fiber optic connections and steps a) -e) are carried out for each of the group's fiber optic connections.
    [13]
    13. Detector device for user optical network terminal equipment of a fiber optic distribution network, where the device (201) comprises:
    - An optical source (401, 501, 601) emitting an optical signal at a certain wavelength;
    - A polarization controller (402, 502, 602) of the optical signal;
    - An optical circulator (403, 503, 603) that comprises three optical ports and is configured to transmit all the optical signal received by the first port (P1) to the second port (P2) of the circulator and to transmit all the optical signal received by the second port (P2) to the third port (P3); or an optical coupler (403, 503, 603) configured to transmit a first percentage of the power of a signal received by a first input / output port to a common port and to transmit a second percentage of the signal received by the common port towards a third inlet / outlet port.
    - An optical meter (404, 504, 604) connected to the third port of the circulator or optical coupler (403, 503, 603).
    [14]
    Device according to claim 13, wherein the output of the device is connected to a fiber optic connection.
    [15]
    Device according to claim 14, wherein the device (201) comprises a processor configured to cause the following actions to be performed:
    - Establish a first polarization by the polarization controller (402, 502, 602) and transmit a first optical signal at the certain wavelength, emitted by the optical source (401, 501,601), with the first polarization through the connection fiber optic;
    - Measure in the optical meter (404, 504, 604) the optical power of the first reflected optical signal, received through the fiber optic connection and the coupler or the optical circulator (403, 503, 603);
    - Establish a second polarization by the polarization controller (402, 502, 602) and transmit a second optical signal at the certain wavelength, emitted by the optical source (410, 501,601), with the second polarization through the connection fiber optic; - Measure in the optical meter (404, 504, 604) the optical power of the second reflected optical signal, received through the fiber optic connection and the coupler or the optical circulator (403, 503, 603).
    [16]
    16. Device according to claim 15 wherein the processor is further configured to: compare the difference between the measured optical powers of the first and second reflected optical signals, with a threshold value; determining the presence of a user optical network terminal equipment optically connected to the fiber optic drop, based on the result of said comparison; and communicating the result of the determination by means of a message through a communication network and / or presenting the result by means of a user interface of the device (201).
    [17]
    17. Device according to any of claims 13-16, wherein the measured optical powers are communicated by means of a message through a communication network and / or by means of a user interface of the device (201).
    [18]
    18. Device according to any of claims 13-17, wherein the fiber optic distribution network is a passive optical network, PON.
    [19]
    19. Device according to any of claims 13-18, wherein the user optical network terminal equipments are ONTs.
    [20]
    20. Device according to any of claims 13-19, wherein the wavelength of the optical signal emitted by the optical source is close to that of the transceiver of an ONT in a passive optical network.
    [21]
    21. Device according to any of claims 13-20, wherein the wavelength of the optical signal emitted by the optical source is 1310 nm.
    [22]
    22. Device according to any of claims 13-21 where the optical source is of the laser or LED type
    [23]
    23. Device according to any of the preceding claims 13-22, where the polarization controller is at the output of the optical source, connected to the first port of the coupler or of the optical circulator or where the polarization controller is connected It is located at the outlet of the common port of the coupler or at the outlet of the second port of the optical circulator, connected to the fiber optic connection.
    [24]
    24. Device according to any of the preceding claims 13-23, wherein the device (201) is connected to a group of several fiber optic connections by means of a switch.
    [25]
    25. Device according to any of the preceding claims 13-24, where the first percentage is 10% and the second percentage is 90%.
    [26]
    26. Device according to any of the preceding claims 13-24, where the first percentage is 5% and the second percentage is 95%.
    [27]
    27. System for detecting the presence of a user optical network terminal equipment, optically connected to a fiber optic connection of a fiber optic distribution network, where the system comprises a device according to any of claims 13-26, at the least one fiber optic drop and at least one optic terminal box, CTO.
    [28]
    28. A computer program comprising computer-executable instructions for implementing the method according to any of claims 1-12, when run on a computer, microprocessor, microcontroller, or any other form of programmable hardware.
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    同族专利:
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    引用文献:
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    JP2002022600A|2000-07-04|2002-01-23|Sumitomo Electric Ind Ltd|Optical cable testing apparatus and method|
    US20130188947A1|2012-01-20|2013-07-25|Electronics And Telecommunications Research Institute|Apparatus and method for monitoring optical line|
    CN103297125A|2013-03-21|2013-09-11|镇江奥菲特光电科技有限公司|Automatic test system for optical fiber splitter|
    US20190280768A1|2018-03-12|2019-09-12|Electronics And Telecommunications Research Institute|Method and device for determining state of optical network terminal line|
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    ES201931016A|ES2827373B2|2019-11-20|2019-11-20|Optical device, method and system for remote detection of optical network terminals|ES201931016A| ES2827373B2|2019-11-20|2019-11-20|Optical device, method and system for remote detection of optical network terminals|
    PCT/ES2020/070720| WO2021099666A1|2019-11-20|2020-11-19|Optical device, method and system for remotely detecting optical network terminals|
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