Time division multiplexing optical module for multimode optical fiber network

Abstract

The utility model discloses a time division multiplexing optical module for a multimode optical fiber network, which is internally provided with a microcontroller and is used for controlling a signal switching unit to gate and switch between a communication signal emission driving array and an OTDR (Optical Time Domain Reflectometer) signal emission driving array so as to drive a laser array to generate n paths of communication optical signals or n paths of OTDR optical pulses, the method comprises the following steps: transmitting an OTDR (Optical Time Domain Reflection) optical pulse into n transmitting optical fibers through a time division multiplexing optical path array in a time division manner, receiving backward reflection and scattering signals generated when the OTDR optical pulse is propagated in the transmitting optical fibers, performing photoelectric conversion through an OTDR detector, performing amplification and other processing through an OTDR processing circuit, and transmitting the signals to a microcontroller, so as to generate data of backward signal intensity changing along with the distance of the optical fibers, the method is used for generating an OTDR test curve and / or an event table. According to the utility model, switching between a high-speed communication function and an optical fiber network diagnosis function is realized by adopting a time division multiplexing technology, and the device can be applied to the application fields of data center communication networks and special optical networks.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical fiber communication, and in particular relates to an optical communication module which can be applied to a multi-mode optical fiber network. Background Art

[0002] Fiber-optic communication is a communication method that uses light waves as information carriers and optical fibers as transmission media. It has become one of the main pillars of modern communications.

[0003] With the continuous development and large-scale application of fiber-optic communication technology, the complexity of fiber-optic networks is increasing. In actual use, when the quality of fiber-optic link connection needs to be maintained and diagnosed, technicians are required to disconnect the fiber-optic network on site, and then use the optical time domain reflectometer (OTDR) to locate and diagnose the fiber-optic link breakpoint event, and then troubleshoot and repair the fiber-optic network, which is time-consuming, labor-intensive and has high maintenance costs.

[0004] In order to solve the above problems, optical modules with integrated OTDR functions have appeared in the field of access network communications. Compared with OTDR test instruments, this type of optical module is relatively small in size and does not need to disconnect the optical fiber network during testing. However, it can only be used in single-mode optical fiber links with a single optical fiber channel and a long optical fiber distance. At the same time, due to the difficulty of integration, the packaging of optical modules with OTDR functions can only be realized in SFP or SFP+ packaging forms.

[0005] In the data center communication field and special optical network application field, compared with the access network communication field, the number of optical fibers in the optical cable is larger, and multiple communication optical signals can be transmitted simultaneously. The optical fibers are mostly multi-mode optical fibers, and the optical modules used are multi-channel optical modules. This type of multi-channel optical module has a small package volume, high transmission rate requirements for communication signals, and short fiber distances in the multi-mode optical fiber links, many fiber connection points, and short fiber lengths between nodes. Therefore, it is impossible to directly transplant the OTDR integration technology of optical modules in the access network communication field to multi-channel optical modules. Therefore, there are currently no multi-channel optical modules with integrated OTDR functions in the industry. Utility Model Content

[0006] The utility model aims to provide a time division multiplexing optical module for a multimode optical fiber network, so as to solve the problem that the multi-channel optical module used in the existing multimode optical fiber network does not have an OTDR function.

[0007] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0008] A time division multiplexing optical module for a multimode optical fiber network, comprising:

[0009] A laser array for converting electrical signals into optical signals;

[0010] A signal switching unit, which is used to select one of the two groups of signals for output;

[0011] A communication signal transmission drive array, which is used to modulate n-channel high-speed communication transmission signals and load them onto the laser array under the gating of the signal switching unit to generate n-channel communication optical signals;

[0012] An OTDR signal emission drive array, which is used to output n narrow pulse electrical signals and drive the laser array to emit n OTDR optical pulses when the signal switching unit is selected;

[0013] A time-division multiplexing optical path array, which is used to inject the n communication optical signals or n OTDR optical pulses into n transmitting optical fibers in a time-division multiplexing manner, and receive back reflection and scattering signals generated when the OTDR optical pulses propagate in the transmitting optical fibers;

[0014] An OTDR detector, which is used to perform photoelectric conversion on n-path back reflection and scattered signals output by the time division multiplexing optical path array;

[0015] An OTDR processing circuit, which is used to amplify, shape, filter, and perform analog-to-digital conversion on n-channel electrical signals output by the OTDR detector, and then output backward signal strength data that varies with time;

[0016] A microcontroller controls the signal switching unit to perform gating switching, and generates data on the variation of the backward signal strength with the optical fiber distance according to the backward signal strength data varying with time, so as to generate an OTDR test curve and / or an event table.

[0017] In some embodiments of the present application, for a multimode fiber optic network, the transmitting optical fiber can be configured as a multimode optical fiber, and the microcontroller can adjust the laser array to output a communication optical signal with a wavelength that is the same as or close to the communication band of the multimode optical fiber according to the communication band of the multimode optical fiber.

[0018] In some embodiments of the present application, in order to reliably receive counter-communication optical signals, a communication receiving optical path array, a communication signal detector and a communication signal amplifier can be set in the optical module; wherein the communication receiving optical path array can be connected to n receiving optical fibers, and is used to focus the counter-communication optical signals transmitted through the n receiving optical fibers, inject them into the communication signal detector for photoelectric conversion, and then output them to the communication signal amplifier for amplification and shaping processing, and then output n-channel high-speed communication receiving signals.

[0019] In some embodiments of the present application, in order to meet the OTDR detection requirements of multimode optical fiber links with a transmission distance of less than three hundred meters, the microcontroller can be configured to control the OTDR signal emission drive array to output a narrow pulse electrical signal of the nanosecond or hundred picosecond level, so as to drive the laser array to output an OTDR optical pulse with a pulse width of the nanosecond or hundred picosecond level, so as to achieve accurate detection of two event points in the multimode optical fiber link that are tens of centimeters or less apart.

[0020] In some embodiments of the present application, in order to obtain a narrow pulse electrical signal of the nanosecond level or the hundred-picosecond level, n narrow pulse electrical signal generating circuits may be provided in the OTDR signal emission drive array, and a NOT gate, an AND gate and an adjustable resistor may be provided in each narrow pulse electrical signal generating circuit, wherein the NOT gate is used to invert a pulse signal output by a microcontroller; the AND gate is used to perform an AND operation on the pulse signal output by the NOT gate and another pulse signal output by the microcontroller to generate an output pulse; the adjustable resistor is connected between the output end of the AND gate and the laser array, and the optical power of the OTDR optical pulse emitted by the laser array is adjusted by changing the driving current applied to the laser array.

[0021] The microcontroller can be configured to change the pulse width of the output pulse generated by the AND gate by adjusting the time difference between the two pulse signals outputted by the microcontroller, thereby obtaining a nanosecond or hundred-picosecond narrow pulse electrical signal. By using the narrow pulse electrical signal to drive the lasers in the laser array to emit light, a nanosecond or hundred-picosecond narrow pulse optical signal can be generated to meet the OTDR detection requirements of multimode optical fiber links with a distance between event points of tens of centimeters or less.

[0022] In some embodiments of the present application, the laser may be a VCSEL laser driven by a small current to meet the driving requirements of the AND gate output pulse for the laser. N VCSEL lasers may be arranged in the laser array, and each VCSEL laser may be driven by one of the narrow pulse electrical signal generating circuits, thereby generating n OTDR optical pulses for OTDR detection of n transmitting optical fibers in a multimode optical fiber link.

[0023] In some embodiments of the present application, in order to meet the miniaturization design of the optical module, a lens substrate, a beam splitter and three groups of lens arrays can be arranged in the time-division multiplexing optical path array; wherein a groove is opened on the lens substrate and an inclined surface is formed, and the inclined surface forms a total reflection surface; the beam splitter is installed in the groove and has two parallel and opposite first and second surfaces, the first surface is a semi-reflective and semi-transmissive surface, and the second surface is a fully transmissive surface; in the three groups of lens arrays, the first group of lens array collimates the communication optical signal or OTDR optical pulse emitted by the laser array to generate a parallel The light beam is transmitted in the lens matrix, then enters the groove and is emitted to the first surface of the beam splitter, and after being reflected by the first surface, it is emitted in parallel to the third lens array, and after being focused by the third lens array, it enters the transmitting optical fiber; the third lens array performs collimation processing on the back reflection and scattered signals returned through the transmitting optical fiber to generate a parallel light beam that enters the lens matrix, and then after being transmitted through the beam splitter, it is emitted in parallel to the inclined surface of the lens matrix, and after being reflected by the inclined surface, it is emitted in parallel to the second lens array, and after being focused by the second lens array, it is emitted to the OTDR detector for photoelectric conversion.

[0024] In this way, a lens substrate and a spectrometer can be used to transmit the communication optical signal and OTDR optical pulse in a time-sharing manner, and to collect the back-reflected and scattered signals. It is small in size and can be directly installed on the PCB board of the optical module, which can significantly reduce the package size of the optical module.

[0025] In some embodiments of the present application, the beam splitter can be installed in the groove at an angle and form a 45° angle with the bottom surface of the groove, and the inclined surface can be formed on the outer surface of the lens substrate adjacent to the second surface of the beam splitter. By changing the propagation direction of the optical signal, the volume of the lens substrate can be limited, which is conducive to the miniaturization design of the optical module.

[0026] In some embodiments of the present application, the three groups of lens arrays can be arranged respectively on two adjacent outer surfaces of the lens substrate, one of the outer surfaces is adjacent to the bottom surface of the groove, and the first group of lens arrays and the second group of lens arrays are arranged thereon, and the arrangement positions can correspond one-to-one to the positions of the groove and the inclined surface respectively; the other outer surface of the lens substrate is adjacent to the first surface of the beam splitter, and the third group of lens arrays can be arranged thereon.

[0027] In some embodiments of the present application, n lenses that are spaced apart and do not interfere with each other can be configured in the three groups of lens arrays to avoid interference between n communication optical signals, n OTDR optical pulses, and n back reflection and scattered signals when they propagate in the lens matrix.

[0028] Compared with the prior art, the advantages and positive effects of the utility model are mainly reflected in:

[0029] 1. The utility model designs an optical module for a multi-channel multi-mode optical fiber communication network, which has a multi-channel parallel high-speed communication function and a multi-channel parallel optical fiber network detection function. The two functions are multiplexed by a laser array, and the function is switched through a signal switching unit, so as to minimize the optical path and circuit scheme, reduce the complexity of the system, and facilitate the miniaturization design of the optical module.

[0030] 2. The utility model adopts time division multiplexing technology and utilizes a signal switching unit to isolate the high-speed communication function and the optical fiber network detection function without affecting each other. During testing, there is no need to disconnect the multi-mode optical fiber network to diagnose the connection status of the multi-mode optical fiber network, which helps to improve the maintenance efficiency of the multi-channel multi-mode optical fiber communication network.

[0031] 3. The utility model sets an OTDR signal emission drive array that can generate narrow pulse electrical signals in the optical module to drive the laser array to emit nanosecond or hundred-picosecond OTDR optical pulses, thereby meeting the OTDR detection needs of multi-mode optical fiber networks with an optical fiber distance of less than 300 meters and a distance between two event points of tens of centimeters or less.

[0032] 4. The optical module of the utility model is particularly suitable for use in optical fiber links in the field of data center communications and special optical network applications to solve the problems of daily management, maintenance and detection of optical fiber networks in this field.

[0033] After reading the detailed description of the embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become more clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 It is a circuit schematic diagram of an embodiment of a narrow pulse optical signal generating circuit;

[0036] Figure 2 yes Figure 1 The waveform diagram of the input pulse and output pulse of the AND gate;

[0037] Figure 3 This is an overall architecture block diagram of an embodiment of a time division multiplexing optical module for a multimode optical fiber network proposed by the utility model;

[0038] Figure 4 yes Figure 3 A schematic structural diagram of an embodiment of a time division multiplexing optical path array;

[0039] Figure 5 yes Figure 3 A schematic structural diagram of an embodiment of a communication receiving optical path array;

[0040] Figure 6 yes Figure 3 A structural schematic diagram of another embodiment of the communication receiving optical path array in FIG. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0042] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore, cannot be understood as a limitation on the present invention. The terms "front" and "rear" are defined according to the transmission direction of electrical or optical signals.

[0043] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances. In the description of the implementation method, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0044] The terms "first", "second", "third", "fourth", and "fifth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", "fourth", and "fifth" may explicitly or implicitly include one or more of the features.

[0045] In the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0046] The OTDR optical modules (optical modules with integrated OTDR functions) in the industry are mainly designed for long-distance single-mode fiber networks. The length of the fiber link ranges from several kilometers to tens of kilometers. The width of the optical pulses emitted by this OTDR optical module for OTDR detection is generally tens of nanoseconds or more, corresponding to a fiber distance resolution of several meters.

[0047] For multimode fiber networks, the length of the fiber link is generally in the range of several meters to three hundred meters, and the distance between two event points (such as two connectors) is tens of centimeters or less. Therefore, optical pulses of tens of nanoseconds cannot meet the OTDR detection requirements of multimode fiber links.

[0048] Therefore, in order to be applicable to short-distance multimode optical fiber transmission links, it is necessary to configure a nanosecond or even hundreds of picosecond narrow pulse optical signal generation circuit in the OTDR optical module.

[0049] like Figure 1 As shown, the narrow pulse optical signal generating circuit of this embodiment is mainly composed of a narrow pulse electrical signal generating circuit and a laser Laser, wherein the narrow pulse electrical signal generating circuit is mainly composed of a microcontroller, a digital gate device, an adjustable resistor R and other components. Among them, the microcontroller outputs two pulse signals IN1 and IN2, and there is a certain delay between the two pulse signals IN1 and IN2, and the delay size can be achieved by the microcontroller by controlling the output time difference of the two pulse signals IN1 and IN2. One of the pulse signals IN1 is transmitted to one input end of the AND gate AND, and the other pulse signal IN2 is inverted through the NOT gate NOT to obtain an inverted pulse signal -IN2 and transmit it to the other input end of the AND gate AND. After the AND gate AND performs an AND operation on the two received pulse signals IN1 and -IN2, an output pulse OUT is generated, which is transmitted to the anode of the laser Laser through the adjustable resistor R1, and the cathode of the laser Laser can be grounded, thereby controlling the light emission of the laser Laser.

[0050] Since there is a time delay between the two inverted pulse signals IN1 and -IN2 entering the AND gate, Figure 2 As shown, therefore, the pulse width of the output pulse OUT generated after the AND gate AND is equal to or slightly less than the delay time between the two inverted pulse signals IN1 and IN2. Therefore, by adjusting the time difference between the two pulse signals IN1 and IN2 output by the microcontroller, a narrow pulse electrical signal of nanoseconds or hundreds of picoseconds can be obtained. By using the narrow pulse electrical signal to drive the laser to emit light, a narrow pulse optical signal of nanoseconds or hundreds of picoseconds can be generated for OTDR detection.

[0051] This embodiment generates nanosecond or picosecond optical pulses by controlling the delay between two pulse signals. The solution is simple and only a small number of gate devices are needed. The gate devices are small in size, so they are easy to integrate and are conducive to the miniaturization of optical module packaging. At the same time, by adjusting the delay between the two pulse signals output by the microcontroller, the pulse width of the generated optical pulse can be adjusted, thereby providing technical support for subsequent intelligent pulse width adjustment.

[0052] In addition, by changing the resistance value of the adjustable resistor R, the optical power of the narrow pulse optical signal emitted by the VCSEL laser can be adjusted.

[0053] Different from the single-channel edge-emitting DFB / FP laser driven by high current in the access network OTDR optical module, this embodiment is aimed at a multi-channel optical module suitable for a multimode optical fiber network. Figure 1 In addition to the multi-channel expansion of the narrow pulse optical signal generating circuit shown in the figure to form an array form, the laser Laser is preferably a surface-emitting, small-current driven VCSEL laser. On the one hand, it can meet the driving of the VCSEL laser by the narrow pulse electrical signal output by the AND gate AND, and on the other hand, it can facilitate the formation of a VCSEL laser array to adapt to the small-size packaging structure of the multi-channel optical module. By reducing the working current of the laser, the power consumption of the optical module can be significantly reduced.

[0054] Based on the above narrow pulse electrical signal generating circuit and its array form, this embodiment designs the following Figure 3 The multi-channel optical module shown has a multi-channel parallel high-speed communication function and a multi-channel parallel optical fiber network intelligent detection function. The two functions use time division multiplexing to achieve function multiplexing and isolation without affecting each other. The connection status of the multi-mode optical fiber network can be monitored without disconnecting the optical fiber network.

[0055] like Figure 3 As shown, the multi-channel optical module of this embodiment mainly includes a communication signal transmission drive array 7, an OTDR signal transmission drive array 8, a signal switching unit 2, a laser array 1, a time division multiplexing optical path array 100, a communication receiving optical path array 200, a communication signal detector 5, a communication signal amplifier 6, an OTDR detector 3, an OTDR processing circuit 4, a microcontroller 9 and other components.

[0056] The communication signal transmission drive array 7 can be directly designed using the laser driving circuit in the existing multi-channel optical module without OTDR function (i.e., using the existing technology), which is used to modulate the multi-channel high-speed communication transmission signal and load it onto the laser array 1 under the gating of the signal switching unit 2. The wavelength λ of the communication optical signal emitted by the laser array 1 is controlled according to the multi-mode optical fiber communication band, so that the wavelength λ is the same as or close to the multi-mode optical fiber communication band, for example, a laser signal with a wavelength of 850nm is output to meet the communication requirements of the multi-mode optical fiber network.

[0057] In this embodiment, the laser array 1 may be an array composed of n VCSEL lasers, where n is equal to the number of channels of the multi-channel optical module.

[0058] The OTDR signal transmission drive array 8 can be used as follows Figure 1 The narrow pulse electrical signal generating circuit composed of the gate device and the adjustable resistor shown is constructed in the form of an array after being expanded into n channels according to the number of channels. The pulse width of the narrow pulse electrical signal output by the OTDR signal emission drive array 8 is controlled by adjusting the time difference between the two pulse signals IN1 and IN2 output by the microcontroller 9, for example, the pulse width of the narrow pulse electrical signal is adjusted to the nanosecond level or the hundred-picosecond level, and under the gating of the signal switching unit 2, the laser array 1 is driven to output a narrow pulse optical signal of the nanosecond level or the hundred-picosecond level, that is, an OTDR optical pulse, for OTDR detection of a multimode optical fiber link.

[0059] In this embodiment, the signal switching unit 2 can be designed with a switch chip having 2n switching channels. Specifically, n of the strobe terminals of the switch chip can be connected to the communication signal emission drive array 7, the other n strobe terminals can be connected to the OTDR signal emission drive array 8, and n common terminals can be connected to the laser array 1. The microcontroller 9 is used to control the action of the switch chip, and the n common terminals of the switch chip are selected to be connected to the communication signal emission drive array 7, or to the OTDR signal emission drive array 8, so as to realize the selective switching between the high-speed communication function and the optical fiber network detection function.

[0060] The n communication optical signals or n OTDR optical pulses emitted by the laser array 1 are injected into the same optical cable via the time division multiplexing optical path array 100. In this embodiment, the optical cable is a section of an optical cable in a multi-channel multimode optical fiber link 10, which integrates n transmitting optical fibers and n receiving optical fibers, each of which is a multimode optical fiber. In this embodiment, one communication optical signal and one OTDR optical pulse are transmitted in each transmitting optical fiber in a time-sharing manner.

[0061] The n-way counter-communication optical signals from the opposite optical module are transmitted to the multi-channel optical module of this embodiment through the n receiving optical fibers in the optical cable. The wavelength of the n-way counter-communication optical signals is also λ, and after being focused by the communication receiving optical path array 200, they are transmitted to the communication signal detector 5 to complete the conversion of the optical signal to the electrical signal. The n-way electrical signals output by the communication signal detector 5 are amplified, shaped, etc. by the communication signal amplifier 6, and can be output to the user side through the electrical interface receiving end on the multi-channel optical module.

[0062] In this embodiment, the communication signal detector 5 and the communication signal amplifier 6 each have n channels, each channel receives a communication optical signal, completes the photoelectric conversion and the amplification and shaping of the electrical signal, and then outputs a high-speed communication reception signal.

[0063] During the propagation of the OTDR optical pulse in the optical fiber link, when encountering the optical fiber connection, break, defect, end face and tail end, a reflection signal will be generated. At the same time, the uneven particles in the optical fiber material will cause Rayleigh scattering. The back reflection and scattered signals are received by the time division multiplexing optical path array 100 and reversely enter the OTDR detector 3 to convert the back light signal into an electrical signal, which is sent to the OTDR processing circuit 4 for amplification, shaping, filtering, high-speed analog-to-digital conversion and other processing. The back signal strength data that varies with time can be obtained and sent to the microcontroller 9. The microcontroller 9 can further process the data to obtain the data on the back signal strength that varies with the optical fiber distance, and the data interface (such as I 2 C interface or SPI interface, etc.) to generate OTDR test curves and / or event tables.

[0064] In this embodiment, the OTDR detector 3 and the OTDR processing circuit 4 each include n channels, and each channel completes processing tasks such as photoelectric conversion, amplification, shaping, filtering, and high-speed analog-to-digital conversion of a backward optical signal.

[0065] The specific working principle of the multi-channel time division multiplexing optical module of this embodiment mainly includes:

[0066] When the multimode optical fiber network connection is normal, the optical module performs the high-speed communication function, and receives the multi-channel high-speed communication transmission signals output by the user side through its electrical interface transmitting end. The microcontroller 9 controls the signal switching unit 2 to switch its common end to be connected with the communication signal transmission driving array 7, and controls the communication signal transmission driving array 7 to complete the modulation of the multi-channel high-speed communication transmission signals, which are loaded onto the laser array 1 through the selection channel of the signal switching unit 2, and drive the laser array 1 to emit multi-channel communication optical signals with a wavelength of λ, thereby realizing the conversion of electrical signals to optical signals.

[0067] The communication optical signal loaded with communication data is converged by the time division multiplexing optical path array 100, and then emitted into the multi-channel multimode optical fiber link 10 through the optical interface of the optical module, and is received by the optical module on the opposite side, thus completing the communication signal transmission function.

[0068] At the same time, the optical module receives the counter-communication optical signal emitted by the opposite optical module through the multi-channel multimode optical fiber link 10, transmits it to the communication signal detector 5 through the communication receiving optical path array 200, converts the optical signal into an electrical signal, and then amplifies and shapes the electrical signal through the communication signal amplifier 6 to generate a high-speed communication receiving signal, which is output to the user side through the electrical interface receiving end of the optical module.

[0069] When the optical fiber network needs to be monitored, or a fault occurs in the optical fiber network, or the microcontroller 9 finds that the communication link is not communicating normally (for example, the received optical power is reduced to a certain set threshold value, etc.), the microcontroller 9 automatically starts the optical fiber network connection monitoring function, controls the signal switching unit 2 to connect its common end with the OTDR signal emission drive array 8, and controls the OTDR signal emission drive array 8 to generate the narrow pulse electrical signal required for OTDR detection, which is transmitted to the laser array 1 via the selection path of the signal switching unit 2 to drive the laser array 1 to emit an OTDR optical pulse with a wavelength of λ, which is focused by the time-division multiplexing optical path array 100 and then emitted into the multi-channel multimode optical fiber link 10 via the optical interface of the optical module to realize the emission of the OTDR optical pulse.

[0070] During the transmission of the OTDR optical pulse in the multi-channel multimode optical fiber link 10, a reflection signal is generated when encountering the optical fiber connection, break, defect, end face and tail end, and a scattering signal is generated when encountering uneven particles in the optical fiber material causing Rayleigh scattering. The back-reflected signal and the back-scattered signal enter the OTDR detector 3 via the time-division multiplexing optical path array 100, and the back-reflected optical signal is converted into an electrical signal. After amplification, shaping, filtering, high-speed analog-to-digital conversion, etc. are performed by the OTDR processing circuit 4, the back-reflected signal strength data that changes with time is obtained and sent to the microcontroller 9.

[0071] The microcontroller 9 further processes the received backward signal strength data varying with time to obtain data on the variation of the backward signal strength with the optical fiber distance, and reports it through the data interface of the optical module to generate an OTDR test curve and / or an event table.

[0072] Due to the use of time division multiplexing, the communication service function and the optical fiber connection status monitoring function are independent of each other and do not interfere with each other. There is no need to disconnect the optical fiber network when monitoring the optical fiber network connection status. Therefore, the application scenarios of the optical module can be expanded. For example, after the optical fiber network wiring is completed, the optical module can be used to scan the connection status of the optical fiber network to obtain a topological diagram of the optical fiber network connection status; or, when the optical module finds that the communication service is abnormal, it can automatically scan, detect, judge and process the optical fiber network to obtain the fault information of the optical fiber network and assist users in repair.

[0073] The multi-channel optical module needs to adopt a multi-channel lens array to realize the multi-channel high-speed communication function. Moreover, the multi-channel optical module of this embodiment also needs to integrate the OTDR detection function on this basis. Therefore, the time division multiplexing optical path array 100 needs to be specially designed.

[0074] Combination Figure 4 As shown, the time-division multiplexing optical path array 100 of this embodiment includes a lens substrate 110, a groove 111 is formed on the lens substrate 110, and a beam splitter 120 is installed in the groove 111. The beam splitter 120 is tilted in the groove 111, for example, it can form a 45° angle with the bottom surface of the groove 111, so as to change the transmission direction of the light. The beam splitter 120 includes two parallel and opposite surfaces 121 and 122, wherein the first surface 121 semi-reflects and semi-transmits light with a wavelength of λ; and the second surface 122 transmits light with a wavelength of λ. On the lens substrate 110, an inclined surface 112 is formed on the outer surface adjacent to the second surface 122 of the beam splitter 120, and the inclined surface 112 is configured as a total reflection surface.

[0075] Lens arrays are arranged on two adjacent outer side surfaces 113 and 114 of the lens base 110, respectively. One of the outer side surfaces 113 is adjacent to the bottom surface of the groove 111, and two groups of lens arrays 141 and 142 are arranged thereon. The positions of the two groups of lens arrays 141 and 142 correspond to the positions of the groove 111 and the inclined surface 112. The other outer side surface 114 of the lens base 110 is adjacent to the first surface 121 of the beam splitter 120, and a third group of lens arrays 143 is arranged thereon.

[0076] In some embodiments, the number of lenses in each lens array 141 - 143 may be respectively matched to the number of channels n of the optical module, and the n lenses in each lens array 141 - 143 are spaced apart from each other and do not interfere with each other.

[0077] In this embodiment, the first group of lens arrays 141 corresponding to the position of the groove 111 can face the laser array 1, and after collimating the communication optical signal or OTDR optical pulse with a wavelength of λ emitted by the laser array 1, a parallel light beam is generated to propagate in the lens substrate 110, and then enters the groove 111 and is emitted to the first surface 121 of the beam splitter 120. After being reflected by the first surface 121 of the beam splitter 120, it is emitted in parallel to the third group of lens arrays 143. After being focused by the third group of lens arrays 143, it enters the multi-channel multimode optical fiber link 10 to realize the emission of high-speed communication optical signals or OTDR optical pulses.

[0078] The OTDR light pulse transmitted in the multi-channel multi-mode optical fiber link 10 generates a back reflection signal when encountering the optical fiber connection, break, defect, end face and tail end, and the back Rayleigh scattering signal generated when encountering the uneven particles in the optical fiber material. The multi-channel multi-mode optical fiber link 10 returns, is collimated by the third lens array 143, generates a parallel light beam and enters the lens base 110, and then is half reflected and half transmitted through the beam splitter 120. The transmitted parallel light beam is directed to the inclined surface 112 of the lens base 110, and after being reflected by the inclined surface 112, it is directed to the second lens array 142 in parallel, and after being focused by the second lens array 142, it is directed to the OTDR detector 3 for photoelectric conversion, so as to realize the reception and detection of the back reflection and scattering signals. Since the OTDR detector 3 only receives half of the back light signal, the microprocessor 9 can multiply the received back signal strength data by 2 to obtain the real back signal strength data. The half of the parallel light beam reflected by the beam splitter 120 is emitted to the first lens array 141 and then emitted to the laser array 1 after being focused, but it does not affect the normal emission of OTDR light pulses by the laser array 1.

[0079] The outer side surface 113 of the lens base 110 can be used as the bottom surface of the lens base 110, and a support foot is formed thereon. The lens base 110 can be directly mounted on the PCB board inside the optical module through the support foot. The laser array 1 and the OTDR detector 3 are mounted on the PCB board and located below the lens base 110. While meeting the communication optical signal and OTDR optical pulse emission and the back reflection and scattered signal reception, the occupied space can be reduced, the packaging size of the optical module can be reduced, and a miniaturized design can be achieved.

[0080] For n-channel counter-communication optical signals transmitted into the optical module through the receiving optical fiber, a communication receiving optical path array 200 can be separately configured in the multi-channel optical module to be dedicated to receiving the counter-communication optical signals.

[0081] like Figure 5As shown, the communication receiving optical path array 200 of this embodiment may include a lens substrate 210, on which a groove 211 is provided, and a reflector 214 is obliquely installed in the groove 211, and the reflector 214 may form a 45° angle with the bottom surface of the groove 211. The outer side surface of the lens substrate 210 adjacent to the bottom surface of the groove 211 is used as the bottom surface 212 of the lens substrate 210, and the fifth lens array 145 is installed thereon. The installation position of the fifth lens array 145 on the bottom surface 212 of the lens substrate should be vertically opposite to the installation position of the reflector 214 in the groove 211. The fourth lens array 144 is installed on an outer side surface 213 of the lens substrate 210 adjacent to the reflective surface of the reflector 214.

[0082] In the fourth lens array 144 and the fifth lens array 145 , n lenses that are spaced apart from each other and do not interfere with each other are respectively arranged.

[0083] The n-way counter-propagation communication optical signals or counter-propagation OTDR optical pulses transmitted through the multi-channel multimode optical fiber link 10 are first injected into the fourth lens array 144 for collimation processing, and then emitted to the reflector 214 after forming a parallel light beam. The reflector 214 has the characteristic of totally reflecting the light with a wavelength of λ, thereby changing the propagation path of the parallel light beam, and emitting to the fifth lens array 145, and then emitting to the communication signal detector 5 after being focused by the fifth lens array 145.

[0084] When the optical modules on the user side and the opposite side perform high-speed communication functions, the microcontroller 9 turns on the communication signal detector 5, and uses the communication signal detector 5 to convert the counter-communication optical signal emitted after being focused by the fifth lens array 145 into an electrical signal, and outputs it to the communication signal amplifier 6, thereby realizing accurate reception of the counter-communication optical signal.

[0085] When the opposite optical module performs the optical fiber network monitoring function, the microcontroller 9 turns off the communication signal detector 5 and ignores the received opposite OTDR optical pulses.

[0086] Of course, if Figure 6 As shown, the communication receiving optical path array 200 of this embodiment can also adopt a lens base 220 to form an inclined surface 221, and configure the inclined surface 221 as a total reflection surface. The fifth lens array 145 is installed on one of the outer surfaces of the lens base 220, and the outer surface is used as the bottom surface 222 of the lens base 220. The fourth lens array 144 is installed on the other outer surface 223 of the lens base 220.

[0087] The n-way counter-propagation communication optical signals or counter-propagation OTDR optical pulses transmitted via the multi-channel multimode optical fiber link 10 are first incident upon the fourth lens array 144 for collimation to form a parallel light beam, and then enter the lens base 220 and are incident upon the inclined surface 221. After being reflected by the inclined surface 221, the propagation path of the parallel light beam is changed and the beam is incident upon the fifth lens array 145. After being focused by the fifth lens array 145, the beam is incident upon the communication signal detector 5.

[0088] When the optical modules on the user side and the opposite side perform high-speed communication functions, the microcontroller 9 turns on the communication signal detector 5, and uses the communication signal detector 5 to convert the counter-communication optical signal emitted after being focused by the fifth lens array 145 into an electrical signal, and outputs it to the communication signal amplifier 6, thereby realizing accurate reception of the counter-communication optical signal.

[0089] When the opposite optical module performs the optical fiber network monitoring function, the microcontroller 9 turns off the communication signal detector 5 and ignores the received opposite OTDR optical pulses.

[0090] In order to facilitate the miniaturization design of the optical module, a foot can be formed on the bottom surface of the lens base 210 / 220, and the lens base 210 / 220 can be directly mounted on the PCB board of the optical module through the foot, and the communication signal detector 5 and the communication signal amplifier 6 can be mounted on the PCB board. The communication signal detector 5 and the communication signal amplifier 6 can be arranged under the lens base 210 / 220 to reduce space occupation and realize small-size packaging of the optical module.

[0091] In this embodiment, the time division multiplexing optical path array 100 and the communication receiving optical path array 200 are directly mounted on the PCB board, which is very close to the laser array 1, the communication signal detector 5, and the OTDR detector 3, thereby ensuring the continuity of high-speed optical signal transmission and meeting the high-speed communication requirements of the multi-mode optical fiber network.

[0092] This embodiment is designed for the data center communication network field and special optical network application field with a large number of optical fiber channels and complex connections, and an optical module that integrates multi-channel parallel high-speed communication function and multi-channel optical fiber network detection function can be widely used in Internet, vehicle-mounted, airborne, ground and other optical fiber communications or Internet of Everything optical fiber networks. Without disconnecting the optical fiber network, it can replace manual completion of automatic detection of the connection status of the multi-channel multi-mode optical fiber network, and is particularly suitable for monitoring the network connection status in scenarios with complex connections or difficult to disassemble and assemble.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the above embodiments, or to replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A time division multiplexing optical module for a multimode optical fiber network, characterized in that: include: A laser array for converting electrical signals into optical signals; A signal switching unit, which is used to select one of the two groups of signals for output; A communication signal transmission drive array, which is used to modulate n-channel high-speed communication transmission signals and load them onto the laser array under the gating of the signal switching unit to generate n-channel communication optical signals; An OTDR signal emission drive array, which is used to output n narrow pulse electrical signals and drive the laser array to emit n OTDR optical pulses when the signal switching unit is selected; A time-division multiplexing optical path array, which is used to inject the n communication optical signals or n OTDR optical pulses into n transmitting optical fibers in a time-division multiplexing manner, and receive back reflection and scattering signals generated when the OTDR optical pulses propagate in the transmitting optical fibers; An OTDR detector, which is used to perform photoelectric conversion on n-path back reflection and scattered signals output by the time division multiplexing optical path array; An OTDR processing circuit, which is used to amplify, shape, filter, and perform analog-to-digital conversion on n-channel electrical signals output by the OTDR detector, and then output backward signal strength data that varies with time; A microcontroller controls the signal switching unit to perform gating switching, and generates data of backward signal strength varying with optical fiber distance according to the backward signal strength data varying with time, so as to generate an OTDR test curve and / or an event table.

2. The time division multiplexing optical module for a multimode optical fiber network according to claim 1, characterized in that: The transmitting optical fiber is a multimode optical fiber, and the microcontroller controls the laser array to output a communication optical signal with a wavelength that is the same as or close to the communication band of the multimode optical fiber.

3. The time division multiplexing optical module for a multimode optical fiber network according to claim 1, characterized in that: Also includes: A communication receiving optical path array, which is connected to the n receiving optical fibers and is used to focus the counter-communication optical signals transmitted through the n receiving optical fibers; A communication signal detector, which is used to receive the n-way counter-communication optical signals output by the communication receiving optical path array and perform photoelectric conversion; The communication signal amplifier is used to amplify and shape the n-channel electrical signals output by the communication signal detector, and then output n-channel high-speed communication receiving signals.

4. The time division multiplexing optical module for a multimode optical fiber network according to any one of claims 1 to 3, characterized in that: The microcontroller controls the OTDR signal transmission drive array to output a narrow pulse electrical signal of nanosecond level or hundred-picosecond level, so as to drive the laser array to output an OTDR optical pulse with a pulse width of nanosecond level or hundred-picosecond level.

5. The time division multiplexing optical module for a multimode optical fiber network according to claim 4, characterized in that: In the OTDR signal transmission drive array, n narrow pulse electrical signal generating circuits are arranged, and each of the narrow pulse electrical signal generating circuits comprises: A NOT gate, which is used to invert a pulse signal output by the microcontroller; An AND gate, which is used to generate an output pulse after performing an AND operation on the pulse signal output by the NOT gate and another pulse signal output by the microcontroller; An adjustable resistor connected between the output end of the AND gate and the laser array, and adjusting the optical power of the optical signal emitted by the laser array by changing the driving current applied to the laser array; The microcontroller changes the pulse width of the output pulse generated by the AND gate by adjusting the time difference between the two pulse signals output by the microcontroller, so as to generate a narrow pulse electrical signal of nanosecond level or hundred-picosecond level.

6. The time division multiplexing optical module for a multimode optical fiber network according to claim 5, characterized in that: In the laser array, n VCSEL lasers driven by small current are arranged.

7. The time division multiplexing optical module for a multimode optical fiber network according to any one of claims 1 to 3, characterized in that: The time division multiplexing optical path array comprises: A lens substrate having a groove formed thereon and an inclined surface formed thereon, wherein the inclined surface forms a total reflection surface; A beam splitter, which is installed in the groove and has two parallel and opposite first and second surfaces, the first surface is a semi-reflective and semi-transmissive surface, and the second surface is a fully transmissive surface; Three lens arrays, among which, The first lens array performs collimation processing on the communication optical signal or OTDR optical pulse emitted by the laser array to generate a parallel light beam which is transmitted in the lens matrix, then enters the groove and is emitted to the first surface of the beam splitter, and after being reflected by the first surface, is emitted in parallel to the third lens array, and after being focused by the third lens array, enters the transmitting optical fiber; The third lens array performs collimation processing on the back reflection and scattered signals returned through the transmitting optical fiber to generate a parallel light beam which enters the lens base, and then is transmitted through the beam splitter and directed parallel to the inclined surface of the lens base, and after being reflected by the inclined surface, is directed parallel to the second lens array, and after being focused by the second lens array, is directed to the OTDR detector for photoelectric conversion.

8. The time division multiplexing optical module for a multimode optical fiber network according to claim 7, characterized in that: The beam splitter is installed in the groove at an angle, forming an angle of 45° with the bottom surface of the groove; The inclined surface is formed on an outer surface of the lens base adjacent to the second surface of the beam splitter.

9. The time division multiplexing optical module for a multimode optical fiber network according to claim 7, characterized in that: The three groups of lens arrays are respectively arranged on two adjacent outer sides of the lens base, one of which is adjacent to the bottom surface of the groove, on which the first group of lens arrays and the second group of lens arrays are arranged, and the arrangement positions correspond one-to-one to the positions of the groove and the inclined surface respectively; the other outer side surface of the lens base is adjacent to the first surface of the beam splitter, on which the third group of lens arrays is arranged.

10. The time division multiplexing optical module for a multimode optical fiber network according to claim 7, characterized in that: In the three groups of lens arrays, n lenses are respectively arranged at intervals and do not interfere with each other.

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