Improved portable emergency dual-service optical fiber multiplexing device

Abstract

The utility model relates to an improved portable emergency dual-service optical fiber multiplexing device, and belongs to the technical field of optical fiber communication. According to the improved portable emergency dual-service optical fiber multiplexing device of the utility model, an uplink and downlink combination and separation module capable of combining and separating uplink and downlink signals and an optical multiplexing module capable of combining and separating two kinds of optical signals are arranged in each of the transmit-receive stations at two sides. Through the arranged uplink and downlink combination and separation module and the optical multiplexing module, the device can construct two communication links at most on the basis of a single-core optical fiber, the use of optical fiber resources is reduced to be one fourth of that of a conventional double-fiber one-way transmission mode, and the device is passive, plug-and-play, flexible in size, convenient to carry, free of a specific installation space and convenient to carry. And an economic and efficient solution is provided for the problem of shortage of optical fiber resources of an electric power communication system.

Description

Technical Field

[0001] This utility model relates to the field of optical fiber communication technology, and in particular to an improved portable emergency dual-service optical fiber multiplexing device. Background Technology

[0002] In conventional fiber optic communication systems, such as Figure 1 As shown, the two stations communicate using a dual-fiber unidirectional transmission method. In a dual-fiber unidirectional transmission system, the uplink and downlink signals are transmitted in different optical fibers, without interfering with each other. Furthermore, the system has a simple structure, making dual-fiber unidirectional transmission the preferred choice for communication systems when power fiber optic cable resources are sufficient.

[0003] However, with the development of fiber optic communication demand, some regions have old optical cables. Due to the limited number of fiber cores in the cables during installation, coupled with broken or abnormally damaged cores, the number of usable idle optical fibers is very limited. The output optical cables at various dispatching terminals have insufficient fiber core resources due to the diverse services and limited transmission capacity, leading to a shortage or complete lack of spare fiber cores in power optical cables. In this situation, establishing new communication links based on dual-fiber unidirectional transmission is no longer feasible. Solving the fiber shortage problem by laying new optical cables or replacing existing ones is not only costly and time-consuming, but also carries the risk of interrupting existing communication links, affecting the communication needs of relevant power plants and dispatching terminals, and posing risks to power grid operation. Furthermore, during emergency repairs and temporary service activations in the power communication network, the existing fiber resources are often insufficient to meet operational needs. Solutions such as laying new optical cables or building new SDH or OTN optical transmission equipment are costly and time-consuming, and cannot address the characteristics of emergency and temporary work.

[0004] Therefore, how to provide a communication device that can utilize optical fiber resources more economically and efficiently in the current context of a shortage of optical fiber resources in power communication systems has become an urgent problem to be solved. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model provides an improved portable emergency dual-service optical fiber multiplexing device, which solves the technical problem that existing optical fiber resource utilization methods are not economical and efficient under the current situation of scarce optical fiber resources in power communication systems.

[0006] In a first aspect, this utility model provides an improved portable emergency dual-service optical fiber multiplexing device, comprising: a first optical multiplexing module, a first uplink / downlink merging / separating module, a second optical multiplexing module, and a second uplink / downlink merging / separating module;

[0007] The uplink transmitting end of the first optical multiplexing module is connected to the uplink end of the first uplink-downlink merging and separating module, the uplink receiving end of the first optical multiplexing module is used to connect to the transmitting end of the transceiver module of station A, the downlink receiving end of the first optical multiplexing module is connected to the downlink end of the first uplink-downlink merging and separating module, the downlink transmitting end of the first optical multiplexing module is used to connect to the receiving end of the transceiver module of station A, and the optical fiber connection end of the first uplink-downlink merging and separating module is used to connect to one end of a single-core optical fiber.

[0008] The uplink transmitting end of the second optical multiplexing module is connected to the uplink end of the second uplink / downlink merging / splitting module, the uplink receiving end of the second optical multiplexing module is used to connect to the transmitting end of the B-station transceiver module, the downlink receiving end of the second optical multiplexing module is connected to the downlink end of the second uplink / downlink merging / splitting module, the downlink transmitting end of the second optical multiplexing module is used to connect to the receiving end of the B-station transceiver module, and the optical fiber connection end of the second uplink / downlink merging / splitting module is used to connect to the other end of the single-core optical fiber.

[0009] Optionally, the first uplink / downlink merging / separating module includes a first optical circulator, and the second uplink / downlink merging / separating module includes a second optical circulator;

[0010] The first end of the first optical circulator is connected to the uplink end of the first uplink-downlink merging and separating module, the third end of the first optical circulator is connected to the downlink end of the first uplink-downlink merging and separating module, and the second end of the first optical circulator is connected to the optical fiber connection end of the first uplink-downlink merging and separating module.

[0011] The first end of the second optical circulator is connected to the uplink end of the second uplink / downlink merging / splitting module, the third end of the second optical circulator is connected to the downlink end of the second uplink / downlink merging / splitting module, and the second end of the second optical circulator is connected to the optical fiber connection end of the second uplink / downlink merging / splitting module.

[0012] Optionally, the first optical multiplexing module includes a first uplink optical multiplexer and a first downlink optical multiplexer, and the second optical multiplexing module includes a second uplink optical multiplexer and a second downlink optical multiplexer;

[0013] The serial communication port of the first uplink optical multiplexer is connected to the uplink transmitter of the first optical multiplexing module, the serial communication port of the first downlink optical multiplexer is connected to the downlink receiver of the first optical multiplexing module, the first port and the second port of the first uplink optical multiplexer are connected to the uplink receiver of the first optical multiplexing module, and the first port and the second port of the first downlink optical multiplexer are connected to the downlink transmitter of the first optical multiplexing module.

[0014] The serial communication port of the second uplink optical multiplexer is connected to the uplink transmitter of the second optical multiplexing module, the serial communication port of the second downlink optical multiplexer is connected to the downlink receiver of the second optical multiplexing module, the first port and the second port of the second uplink optical multiplexer are connected to the uplink receiver of the second optical multiplexing module, and the first port and the second port of the second downlink optical multiplexer are connected to the downlink transmitter of the second optical multiplexing module.

[0015] Optionally, the transceiver module of station A includes a first transceiver module and a second transceiver module, and the transceiver module of station B includes a third transceiver module and a fourth transceiver module. The first transceiver module and the third transceiver module have the same transceiver frequency, and the second transceiver module and the fourth transceiver module have the same transceiver frequency.

[0016] The transmitting end of the first transceiver module is connected to the first port of the first uplink optical multiplexer, the transmitting end of the second transceiver module is connected to the second port of the first uplink optical multiplexer, the receiving end of the first transceiver module is connected to the first port of the first downlink optical multiplexer, and the receiving end of the second transceiver module is connected to the second port of the first downlink optical multiplexer.

[0017] The transmitting end of the third transceiver module is connected to the first port of the second uplink optical multiplexer, the transmitting end of the fourth transceiver module is connected to the second port of the second uplink optical multiplexer, the receiving end of the third transceiver module is connected to the first port of the second downlink optical multiplexer, and the receiving end of the fourth transceiver module is connected to the second port of the second downlink optical multiplexer.

[0018] Optionally, the first uplink optical multiplexer, the first downlink optical multiplexer, the second uplink optical multiplexer, and the second downlink optical multiplexer are all wavelength division multiplexers.

[0019] Optionally, both the first optical circulator and the second optical circulator are quasi-circulators, with the first terminal of the first optical circulator not connected to the third terminal, and the first terminal of the second optical circulator not connected to the third terminal.

[0020] Optionally, the length of the single-core optical fiber is no more than 20km.

[0021] Optionally, the wavelength of the optical signals transmitted and received by the first transceiver module and the third transceiver module is 1310nm, and the wavelength of the optical signals transmitted and received by the second transceiver module and the fourth transceiver module is 1550nm.

[0022] The above scheme has the following beneficial effects:

[0023] This improved portable emergency dual-service fiber optic multiplexing device incorporates an uplink / downlink merging / splitting module for combining and separating uplink and downlink signals, and an optical multiplexing module for combining and separating two types of optical signals, at each of the two transceiver stations. Through these modules, the device can construct up to two communication links based on a single-core fiber, reducing fiber optic resource usage to one-quarter of that of conventional dual-fiber unidirectional transmission. Furthermore, the device is passive, plug-and-play, compact, and portable, requiring no specific installation space, providing an economical and efficient solution to the problem of scarce fiber optic resources in power communication systems. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a conventional dual-fiber unidirectional transmission communication method;

[0025] Figure 2 This is a schematic diagram of the structure of an improved portable emergency dual-service optical fiber multiplexing device provided in one embodiment of the present invention;

[0026] The symbols are explained as follows:

[0027] 201. First uplink / downlink merging / separation module; 202. Second uplink / downlink merging / separation module; 203. First optical multiplexing module; 204. Second optical multiplexing module; 205. Station A transceiver module; 206. Station B transceiver module. Detailed Implementation

[0028] To make the technical problems, technical solutions and beneficial effects solved by this utility model clearer, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and embodiments.

[0029] It should be understood that the embodiments described below represent essential information to enable those skilled in the art to implement the embodiments and to illustrate the best mode of implementation. Upon reading the following description in conjunction with the accompanying drawings, those skilled in the art will understand the concepts of this disclosure and recognize the applications of these concepts not specifically mentioned herein. It should be understood that these concepts and applications fall within the scope of this disclosure and the appended claims.

[0030] It should also be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of this disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0031] It should also be understood that when a component is referred to as "connected" or "coupled" to another component, it can be directly connected or coupled to the other component, or there may be intermediate components. Conversely, when an element is referred to as "directly connected" or "directly coupled" to another element, there are no intermediate components.

[0032] It should also be understood that the terms “upper,” “lower,” “left,” “right,” “front,” “back,” “bottom,” “middle,” “center,” “top,” etc., may be used herein to describe various elements, indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing the present invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, these elements should not be limited by these terms.

[0033] These terms are used only to distinguish one element from another. For example, a first element may be referred to as the “upper” element, and similarly, a second element may be referred to as the “upper” element depending on the relative orientation of these elements, without departing from the scope of this disclosure.

[0034] To be further understood, the terms “comprising,” “including,” “including,” and / or “include” as used herein specify the presence of the said feature, integer, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0035] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that the terms used herein should be interpreted as having the same meaning as they mean in the context of this specification and related art, and will not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0036] In one embodiment, a method such as Figure 2 The improved portable emergency dual-service fiber optic multiplexing device shown includes: a first optical multiplexing module 203, a first uplink / downlink merging / splitting module 201, a second optical multiplexing module 204, and a second uplink / downlink merging / splitting module 202.

[0037] The first uplink / downlink merging and separating module 201 and the second uplink / downlink merging and separating module 202 are used to send the multiplexed and combined optical signal to the optical fiber or to receive the multiplexed and combined optical signal from the optical fiber. Therefore, the optical fiber connection end of the first uplink / downlink merging and separating module 201 and the optical fiber connection end of the second uplink / downlink merging and separating module 202 are used to connect the two ends of a single-core optical fiber, respectively.

[0038] The function of the first optical multiplexing module 203 and the second optical multiplexing module 204 is to combine and separate different signals to achieve signal transmission. Combining is to achieve transmission on a single-core optical fiber, and separation is to restore different types of signals to successfully transmit information. Therefore, the combined signal formed by the first optical multiplexing module 203 and the second optical multiplexing module 204 will be sent to the corresponding uplink and downlink combining and separating modules through the uplink transmitter. The combined signal sent by the other site will need to be separated and restored by the first optical multiplexing module 203 and the second optical multiplexing module 204.

[0039] Therefore, the uplink transmitting end of the first optical multiplexing module 203 is connected to the uplink end of the first uplink / downlink merging / separating module 201, and the downlink end of the first uplink / downlink merging / separating module 201 is connected to the downlink receiving end of the first optical multiplexing module 203; the uplink transmitting end of the second optical multiplexing module 204 is connected to the uplink end of the second uplink / downlink merging / separating module 202, and the downlink end of the second uplink / downlink merging / separating module 202 is connected to the downlink receiving end of the second optical multiplexing module 204.

[0040] Furthermore, the signals combined by the first optical multiplexing module 203 and the second optical multiplexing module 204 need to originate from the in-station transceiver module, and the separated and restored signals also need to be sent to the in-station transceiver module. Therefore, this embodiment limits the uplink receiving end of the first optical multiplexing module 203 to be used to connect to station A (i.e., Figure 2 The transmitting end of the transceiver module at station A is shown. The downlink transmitting end of the first optical multiplexing module 203 is used to connect to the receiving end of the transceiver module at station A, and the uplink receiving end of the second optical multiplexing module 204 is used to connect to station B (i.e., Figure 2 The transmitting end of the transceiver module (as shown in the diagram) of Station B, and the downlink transmitting end of the second optical multiplexing module 204 are used to connect to the receiving end of the transceiver module of Station B, so as to successfully and accurately realize the merging and separation of the optical signals to be transmitted and received in actual use.

[0041] The improved portable emergency dual-service fiber optic multiplexing device described in this embodiment is equipped with an uplink / downlink merging / splitting module capable of merging and separating uplink / downlink signals, and an optical multiplexing module capable of merging and separating two types of optical signals, in each of the two transceiver stations. Therefore, the overall characteristics of this device are as follows:

[0042] 1) By using a single fiber, one or two dual-core services can be transmitted. Compared with the conventional dual-fiber unidirectional transmission method, the use of fiber resources is reduced to one-quarter, which can save 75% of fiber core resources and greatly improve the communication capacity of the fiber optic communication system.

[0043] 2) The equipment is passive and does not require a separate AC or DC power supply, saving the process of finding a power source for the equipment;

[0044] 3) The equipment is plug-and-play, requiring no network management system deployment, saving time and costs associated with network management system installation and debugging;

[0045] 4) The equipment has a simple structure, compact size, and is easy to carry. It does not need to be installed on a rack, and there is no need to find a specific installation space for the equipment.

[0046] In this embodiment, when a fiber optic cable core fails or a new service needs to be activated, the device can transmit one or two dual-core services as long as one fiber core is normal. This meets the needs of emergency service restoration and temporary service activation in emergency situations, improves fiber optic resource utilization, enhances the quality of communication maintenance, and provides strong support for emergency repair of power communication fiber optic faults. It effectively solves the problem of insufficient fiber optic resources in power communication systems during emergency repairs and the activation of temporary services with a fast, efficient, and economical solution.

[0047] In one embodiment, such as Figure 2 As shown, the first uplink / downlink merging / separating module 201 specifically includes a first optical circulator, and the second uplink / downlink merging / separating module 202 specifically includes a second optical circulator.

[0048] Among them, the first optical circulator is also Figure 2 The optical circulator 1 shown, the second optical circulator is also... Figure 2 The optical circulator 2 shown in the figure.

[0049] An optical circulator is a multi-port optical device with non-reciprocal characteristics. When an optical signal is input from any port, it is output from the next port in digital order with very little loss. If a signal is input from port 1, the signal can only be output from port 2; similarly, a signal input from port 2 can only be output from port 3, and so on. Hence, it is called a circulator.

[0050] Based on the principle of an optical circulator, it is known that port 2 can receive optical signals from port 1 and send optical signals to port 3. Therefore, in this embodiment, port 1 of the optical circulator receives the uplink signal sent by the corresponding optical multiplexing module and then sends it uplink to the optical fiber through port 2. The optical signal is then received by the optical fiber through port 2 of the optical circulator and sent downlink to the corresponding optical multiplexing module through port 3.

[0051] Based on this, the first end (port 1) of the first optical circulator (optical circulator 1) is connected to the uplink end of the first uplink-downlink merging and separating module, the third end (port 3) of the first optical circulator is connected to the downlink end of the first uplink-downlink merging and separating module, and the second end (port 2) of the first optical circulator is connected to the optical fiber connection end of the first uplink-downlink merging and separating module, so as to realize the transmission and reception of uplink and downlink signals by the optical circulator.

[0052] Similarly, the first end (port 1) of the second optical circulator (optical circulator 2) is connected to the uplink end of the second uplink / downlink merging / splitting module, the third end (port 3) of the second optical circulator is connected to the downlink end of the second uplink / downlink merging / splitting module, and the second end (port 2) of the second optical circulator is connected to the fiber optic connection end of the second uplink / downlink merging / splitting module.

[0053] This embodiment utilizes the characteristic that optical signals in an optical circulator can only be output from the port following the input port, and that there is almost no loss at the output port and almost no output at other ports, to achieve accurate merging and separation of uplink and downlink signals in the improved portable emergency dual-service optical fiber multiplexing device of this invention, thereby improving the optical signal transmission effect.

[0054] To further improve the merging and separation effect of uplink and downlink optical signals by the optical circulator and thus improve the optical signal transmission effect, based on the principle that ports 1 and 3 do not need to be connected during the operation of the optical circulator, in a preferred embodiment, both the first optical circulator and the second optical circulator are selected as quasi-circulators, wherein the first end (port 1) and the third end (port 3) are not connected.

[0055] In one embodiment, such as Figure 2 As shown, the first optical multiplexing module 203 includes a first uplink optical multiplexer and a first downlink optical multiplexer, and the second optical multiplexing module 204 includes a second uplink optical multiplexer and a second downlink optical multiplexer.

[0056] Among them, the first uplink optical multiplexer is optical multiplexer 11, the first downlink optical multiplexer is optical multiplexer 12, the second uplink optical multiplexer is optical multiplexer 21, and the second downlink optical multiplexer is optical multiplexer 22.

[0057] An optical multiplexer can combine and separate two different optical signals, integrating them into a single signal that propagates on a single-core optical fiber. Therefore, it generally includes two ports for transmitting and receiving the original optical signals (i.e., ports for receiving and transmitting signals λ1 and λ2), as well as a serial communication port (i.e., a COM port) for transmitting and receiving the combined optical signal.

[0058] Therefore, in this embodiment, the serial communication port of the first uplink optical multiplexer is connected to the uplink transmitter of the first optical multiplexing module, the uplink transmitter of the first optical multiplexing module is connected to port 1 of the optical circulator 1, the serial communication port of the first downlink optical multiplexer is connected to the downlink receiver of the first optical multiplexing module, the downlink receiver of the first optical multiplexing module is connected to port 3 of the optical circulator 1, the first port and the second port of the first uplink optical multiplexer are connected to the uplink receiver of the first optical multiplexing module to receive the uplink optical signal sent by the corresponding intra-station transceiver module, and the first port and the second port of the first downlink optical multiplexer are connected to the downlink transmitter of the first optical multiplexing module to send the downlink optical signal to the corresponding intra-station transceiver module.

[0059] Similarly, the serial communication port of the second uplink optical multiplexer is connected to the uplink transmitter of the second optical multiplexing module, the uplink transmitter of the second optical multiplexing module is connected to port 1 of the optical circulator 2, the serial communication port of the second downlink optical multiplexer is connected to the downlink receiver of the second optical multiplexing module, the downlink receiver of the second optical multiplexing module is connected to port 3 of the optical circulator 2, the first and second ports of the second uplink optical multiplexer are connected to the uplink receiver of the second optical multiplexing module to receive the uplink optical signal sent by the corresponding intra-station transceiver module, and the first and second ports of the second downlink optical multiplexer are connected to the downlink transmitter of the second optical multiplexing module to send downlink optical signals to the corresponding intra-station transceiver module.

[0060] In this embodiment, an optical multiplexer is selected to form an optical multiplexing module. With the help of the excellent performance of the optical multiplexer in combining and separating two different signals, the improved portable emergency dual-service optical fiber multiplexing device of this invention can effectively combine and restore the signals of two communication links, thus providing a guarantee for the propagation of two communication link signals in a single-core optical fiber.

[0061] Furthermore, in a preferred embodiment, the optical multiplexer in the above embodiment is specifically a wavelength division multiplexer. In other embodiments, the operator may select any feasible type of optical multiplexer, such as a frequency division multiplexer or a time division multiplexer, as appropriate.

[0062] In one embodiment, such as Figure 2 As shown, based on the above embodiments, each optical multiplexing module specifically includes an uplink optical multiplexer and a downlink optical multiplexer, and each optical multiplexer includes two ports for communication with the station's transceiver module. Therefore, this embodiment is configured as follows:

[0063] Station A's transceiver module includes a first transceiver module and a second transceiver module, while Station B's transceiver module includes a third transceiver module and a fourth transceiver module. The first and third transceiver modules have the same transceiver frequency, and the second and fourth transceiver modules have the same transceiver frequency.

[0064] Station A is one of them. Figure 2 Station A and Station B are shown below. Figure 2 As shown in the Bilibili example, the first and third transceiver modules are 1310nm dual-fiber transceiver modules, while the second and fourth transceiver modules are 1550nm dual-fiber transceiver modules.

[0065] The transmitting end (TX end) of the first transceiver module is connected to the first port of the first uplink optical multiplexer, the transmitting end of the second transceiver module is connected to the second port of the first uplink optical multiplexer, the receiving end (RX end) of the first transceiver module is connected to the first port of the first downlink optical multiplexer, and the receiving end of the second transceiver module is connected to the second port of the first downlink optical multiplexer.

[0066] The transmitting end of the third transceiver module is connected to the first port of the second uplink optical multiplexer, the transmitting end of the fourth transceiver module is connected to the second port of the second uplink optical multiplexer, the receiving end of the third transceiver module is connected to the first port of the second downlink optical multiplexer, and the receiving end of the fourth transceiver module is connected to the second port of the second downlink optical multiplexer.

[0067] Based on the above connection method, the overall signal flow is as follows: the 1310nm service light from station A enters through port λ1 of optical multiplexer 1, and the 1550nm service light enters through port λ2 of optical multiplexer 1. After being combined by optical multiplexer 1, the light is output from the COM port, then enters optical circulator port 1 and is output from port 2. After transmission through optical fiber, it reaches optical circulator port 2 of station B, and is then output from port 3 to optical multiplexer 2 of station B. Optical multiplexer 2 then separates the 1310nm and 1550nm optical signals. The 1310nm optical signal is output from port λ1 to the 1310nm transceiver module, and the 1550nm optical signal is output from port λ2 to the 1550nm transceiver module. The optical signal sent by station B can also reach the transceiver module of station A in the same way. The improved portable emergency dual-service fiber optic multiplexer achieves the merging and separation of two optical signals of the same wavelength in uplink and downlink by using optical multiplexers and optical circulators, while the optical transceiver modules at both ends are exactly the same as those in a dual-fiber unidirectional transmission system.

[0068] This embodiment is based on the above embodiment where each optical multiplexing module includes an uplink optical multiplexer and a downlink optical multiplexer, which can realize the construction of dual communication links for two stations. Therefore, this embodiment limits the type of in-station transceiver module connected to the optical multiplexing module and the specific connection method with the optical multiplexer in the optical multiplexing module, and clarifies the specific details of the method for realizing two communication links based on a single-core optical fiber.

[0069] In this embodiment, two types of in-station transceiver modules connected to the optical multiplexing module are configured to transmit and receive optical signals with wavelengths of 1310nm and 1550nm, respectively. In other embodiments, the operator can set the specific specifications of the transmitted and received optical signals according to requirements, as long as the specifications of the transmitted and received optical signals of the two in-station transceiver modules are different.

[0070] Furthermore, regarding the transmission distance supported by the device of the present invention, the analysis is as follows:

[0071] Theoretical Analysis:

[0072] In the SDH communication system design specification, the relay design method in the optical synchronous digital transmission system adopts the worst-case method. This means that all system parameters are calculated using worst-case values ​​(considering equipment aging and changes in ambient temperature and humidity). The transmission system parameters at different rates are based on a bit error rate that is not inferior to... It was developed as a standard. Different transmission rates result in different bit error rates. The corresponding receiver OSNR tolerances differ. Taking an STM-64 transmission system as an example, its receiver OSNR tolerance at the end of its lifespan is 20 dB, and the sum of the optical channel OSNR cost and the optical channel OSNR margin is 5 dB. Therefore, the OSNR at the receiver of an STM-64 system should not be less than 25 dB.

[0073] The transmission distance of a single-fiber bidirectional transmission system based on a portable emergency dual-service fiber multiplexer is limited by backscattering Rayleigh noise. Taking an STM-64 rate transmission system as an example, the maximum transmission distance of this system using a single-fiber bidirectional transmission system with the same wavelength is calculated.

[0074] The OSNR requirements for the receiver of a transmission system at STM-64 rate are as follows:

[0075]

[0076] in, The received signal optical power is expressed in dBm. The noise power at the receiving end is expressed in dBm. In a single-fiber bidirectional transmission system with the same wavelength built upon a portable emergency dual-service fiber multiplexer, The primary source of this is backscattering by Rayleigh, and the power of the backscattered light is 31–36 dB lower than that of the incident light. For ease of calculation, a midpoint of 33 dB is used. The calculation formula is simplified to:

[0077]

[0078] In the formula, This represents the optical power of the transmitting signal, measured in dBm.

[0079] The theoretical formula for calculating OSNR-limited transmission distance is as follows:

[0080]

[0081] In the formula The maximum optical channel cost is set to 2 dB;

[0082] The sum of losses of all active connectors between the transmitter and receiver is given, with each connector attenuation set to 0.5 dB. If the optical circulator pigtail is directly connected to the transceiver module port in a single-fiber bidirectional transmission system based on a portable emergency dual-service fiber multiplexer, then the number of active connectors in the system is 2.

[0083] Average attenuation coefficient of an optical fiber;

[0084] Average loss of a fixed fusion splice for optical fiber. Take 0.20 dB / km;

[0085] The fiber optic cable redundancy factor is set to 0.04 dB / km.

[0086] Combining the three formulas above, the maximum transmission distance of a single-fiber bidirectional transmission system based on a portable emergency dual-service fiber multiplexer at STM-64 rate can be calculated to be 21 km. Similarly, calculations show that the maximum transmission distances at STM-1 / 4 / 16 / 64 rates are approximately 108 km, 83 km, 54 km, and 21 km, respectively.

[0087] Actual test verification:

[0088] The maximum transmission distance of a single-fiber bidirectional transmission system based on the SDH transmission standard was tested at different transmission rates. The experimental system used an SDH bit error rate meter to measure the bit error rate. The SDH bit error rate meter integrated an optical transceiver module, allowing for arbitrary adjustment of the transmission rate. Transmission performance tests were conducted on the system at STM-1 / 4 / 16 / 64 rates. The signal light used non-return-to-zero code direct intensity modulation at a wavelength of 1550 nm, with a signal extinction ratio of approximately 10 dB and a transmit optical power of 1 dBm. At different transmission rates, by gradually increasing the transmission distance until the bit error rate at the receiving end approached 10, the measured maximum transmission distances at STM-1 / 4 / 16 / 64 rates were approximately 110 km, 80 km, 50 km, and 20 km, respectively. The experimental results are in good agreement with the theoretical calculations.

[0089] Therefore, in order to ensure that the improved portable emergency dual-service optical fiber multiplexing device of the present invention can work reasonably under various conditions, in a preferred embodiment, the length of the single-core optical fiber connected between the first uplink / downlink merging / separating module and the second uplink / downlink merging / separating module, that is, between port 2 of optical circulator 1 and port 2 of optical circulator 2, is limited to no more than 20km.

[0090] Of course, as can be seen from the above analysis, the maximum signal transmission distance of the improved portable emergency dual-service fiber optic multiplexing device of the present invention is not always 20km. In other embodiments, the operator can also limit the maximum transmission distance according to the actual transmission rate.

[0091] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. An improved portable emergency dual-service fiber optic multiplexing device, characterized in that, include: The system comprises a first optical multiplexing module, a first uplink / downlink merging / de-merging module, a second optical multiplexing module, and a second uplink / downlink merging / de-merging module; The uplink transmitting end of the first optical multiplexing module is connected to the uplink end of the first uplink-downlink merging and separating module, the uplink receiving end of the first optical multiplexing module is used to connect to the transmitting end of the transceiver module of station A, the downlink receiving end of the first optical multiplexing module is connected to the downlink end of the first uplink-downlink merging and separating module, the downlink transmitting end of the first optical multiplexing module is used to connect to the receiving end of the transceiver module of station A, and the optical fiber connection end of the first uplink-downlink merging and separating module is used to connect to one end of a single-core optical fiber. The uplink transmitting end of the second optical multiplexing module is connected to the uplink end of the second uplink / downlink merging / splitting module, the uplink receiving end of the second optical multiplexing module is used to connect to the transmitting end of the B-station transceiver module, the downlink receiving end of the second optical multiplexing module is connected to the downlink end of the second uplink / downlink merging / splitting module, the downlink transmitting end of the second optical multiplexing module is used to connect to the receiving end of the B-station transceiver module, and the optical fiber connection end of the second uplink / downlink merging / splitting module is used to connect to the other end of the single-core optical fiber.

2. The improved portable emergency dual-service fiber optic multiplexing device according to claim 1, characterized in that, The first uplink / downlink merging / separating module includes a first optical circulator, and the second uplink / downlink merging / separating module includes a second optical circulator; The first end of the first optical circulator is connected to the uplink end of the first uplink-downlink merging and separating module, the third end of the first optical circulator is connected to the downlink end of the first uplink-downlink merging and separating module, and the second end of the first optical circulator is connected to the optical fiber connection end of the first uplink-downlink merging and separating module. The first end of the second optical circulator is connected to the uplink end of the second uplink / downlink merging / splitting module, the third end of the second optical circulator is connected to the downlink end of the second uplink / downlink merging / splitting module, and the second end of the second optical circulator is connected to the optical fiber connection end of the second uplink / downlink merging / splitting module.

3. The improved portable emergency dual-service fiber optic multiplexing device according to claim 1, characterized in that, The first optical multiplexing module includes a first uplink optical multiplexer and a first downlink optical multiplexer, and the second optical multiplexing module includes a second uplink optical multiplexer and a second downlink optical multiplexer; The serial communication port of the first uplink optical multiplexer is connected to the uplink transmitter of the first optical multiplexing module, the serial communication port of the first downlink optical multiplexer is connected to the downlink receiver of the first optical multiplexing module, the first port and the second port of the first uplink optical multiplexer are connected to the uplink receiver of the first optical multiplexing module, and the first port and the second port of the first downlink optical multiplexer are connected to the downlink transmitter of the first optical multiplexing module. The serial communication port of the second uplink optical multiplexer is connected to the uplink transmitter of the second optical multiplexing module, the serial communication port of the second downlink optical multiplexer is connected to the downlink receiver of the second optical multiplexing module, the first port and the second port of the second uplink optical multiplexer are connected to the uplink receiver of the second optical multiplexing module, and the first port and the second port of the second downlink optical multiplexer are connected to the downlink transmitter of the second optical multiplexing module.

4. The improved portable emergency dual-service fiber optic multiplexing device according to claim 3, characterized in that, The transceiver module of station A includes a first transceiver module and a second transceiver module, and the transceiver module of station B includes a third transceiver module and a fourth transceiver module. The first transceiver module and the third transceiver module have the same transceiver frequency, and the second transceiver module and the fourth transceiver module have the same transceiver frequency. The transmitting end of the first transceiver module is connected to the first port of the first uplink optical multiplexer, the transmitting end of the second transceiver module is connected to the second port of the first uplink optical multiplexer, the receiving end of the first transceiver module is connected to the first port of the first downlink optical multiplexer, and the receiving end of the second transceiver module is connected to the second port of the first downlink optical multiplexer. The transmitting end of the third transceiver module is connected to the first port of the second uplink optical multiplexer, the transmitting end of the fourth transceiver module is connected to the second port of the second uplink optical multiplexer, the receiving end of the third transceiver module is connected to the first port of the second downlink optical multiplexer, and the receiving end of the fourth transceiver module is connected to the second port of the second downlink optical multiplexer.

5. The improved portable emergency dual-service fiber optic multiplexing device according to claim 3 or 4, characterized in that, The first uplink optical multiplexer, the first downlink optical multiplexer, the second uplink optical multiplexer, and the second downlink optical multiplexer are all wavelength division multiplexers.

6. The improved portable emergency dual-service fiber optic multiplexing device according to claim 2, characterized in that, Both the first optical circulator and the second optical circulator are quasi-circulators. The first terminal of the first optical circulator is not connected to the third terminal, and the first terminal of the second optical circulator is not connected to the third terminal.

7. The improved portable emergency dual-service fiber optic multiplexing device according to claim 1, characterized in that, The length of the single-core optical fiber is no more than 20km.

8. The improved portable emergency dual-service fiber optic multiplexing device according to claim 4, characterized in that, The wavelength of the optical signals transmitted and received by the first transceiver module and the third transceiver module is 1310nm, and the wavelength of the optical signals transmitted and received by the second transceiver module and the fourth transceiver module is 1550nm.

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