Equipment for managing optical submarine communication systems, submarine communication systems

Abstract

To provide an apparatus for managing a subsea optical communications system.SOLUTION: An apparatus for managing optical subsea communications system includes a plurality of fiber interface modules (FIMs), where each FIM comprises a receive part and a transmit part. The transmit part includes two normally closed switches SW1, SW2, where a first switch of the two normally closed switches is coupled to a line monitoring equipment (LME) TX port, and where a second switch of the two normally closed switches is coupled to a line terminating equipment (LTE) TX port.SELECTED DRAWING: Figure 4A

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority to patent applications for inventions entitled "Terminal Line Interface Module for Undersea Open Cable System Access" filed on January 18, 2021, with U.S. Provisional Application No. 63 / 138,650, and "Terminal Line Interface Module for Undersea Open Cable System Access" filed on January 7, 2021, with U.S. Provisional Application No. 63 / 134,814, and incorporates the entire disclosures of these two applications by reference herein.

[0002] Embodiments of the present disclosure relate to the field of optical communication systems. In particular, the present disclosure relates to at least a terminal line interface module for accessing an undersea open cable system.

Background Art

[0003] Long - distance optical communication systems (e.g., undersea optical communication systems) may include many interconnected optical cables to facilitate the transmission of data and information. The optical cables may be trunk cables and may include bidirectional trunk fiber pairs.

[0004] The submarine optical communication system may include a "wet equipment" component and a "dry equipment" component. The wet equipment component of the system may include all things that may be underwater, such as submarine cables, underwater repeaters or amplifiers, branching units, etc. The dry equipment component may include equipment that can be deployed at a cable landing station, such as submarine line terminal equipment (SLTE), power feed equipment (PFE), and line monitoring equipment. [Overview of the project] [Means for solving the problem]

[0005] In one embodiment, a device for managing an optical submarine communication system is provided. The device may comprise a plurality of fiber interface modules (FIMs), each FIM including a receiving unit and a transmitting unit. The transmitting unit may comprise two normally closed switches, the first of which is coupled to a line monitoring equipment (LME) TX port, and the second of which is coupled to a line terminating equipment (LTE) TX port.

[0006] In another embodiment, a submarine communication system is provided comprising a wet equipment and an interface module assembly coupled to the wet equipment. The interface module assembly may comprise a plurality of fiber interface modules (FIMs), each FIM comprising a receiving unit and a transmitting unit, the transmitting unit comprising two normally closed switches. Thus, the first of the two normally closed switches may be coupled to a Line Monitoring Equipment (LME) TX port, and the second of the two normally closed switches may be coupled to an LTE (Long-Term Terminal) TX port.

[0007] In another embodiment, a submarine communication system is provided comprising a wet device and an interface module assembly coupled to the wet device. The interface module assembly may comprise a plurality of fiber interface modules (FIMs), each FIM comprising a receiving unit and a transmitting unit. The transmitting unit may have two normally closed switches, the first of which is coupled to a Line Monitoring Equipment (LME) TX port, and the second of which is coupled to an LTE (Long-Term Terminal) TX port. The FIM may further comprise at least one amplifier coupled between its ports. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing an example of an optical communication system. [Figure 2] This figure shows an example 1 of an optical interconnection component for wet equipment. [Figure 3] This figure shows example 2 of an optical interconnection component for wet equipment. [Figure 4A] This figure shows example 1 of an open cable fiber pair (FP) line interface module. [Figure 4B] This figure shows example 2 of an open cable fiber pair (FP) line interface module. [Figure 4C] This figure shows example 3 of an open cable fiber pair (FP) line interface module. [Figure 4D] This figure shows example 4 of an open cable fiber pair (FP) line interface module. [Figure 4E] This figure shows example 5 of an open cable fiber pair (FP) line interface module. [Figure 5] This figure shows an example of a cage for multiple FP line interface modules. [Modes for carrying out the invention]

[0009] This embodiment relates to a terminal line interface module for accessing at least a submarine open cable system. As the embodiment and as will be described in more detail below, each module may be capable of servicing one fiber pair and may include at least two reliable normally closed switches. For example, the switching capability can adapt to the reconfiguration of a dark fiber pair and a bright fiber pair, and once the fiber pair is lit, time-domain optical reflectometer (OTDR) measurements can be made.

[0010] The present invention will now be described more comprehensively below with reference to the drawings, which illustrate various embodiments. However, the subject matter of this disclosure can be implemented in many different forms and should not be construed as being limited to the embodiments described herein. On the contrary, these embodiments are provided to make the invention thorough and complete and to fully convey the scope of the invention to those skilled in the art. In the drawings, the same reference numeral always refers to the same component.

[0011] Referring to the drawing, Figure 1 shows an example of a bidirectional optical communication system (abbreviated as optical communication system 101), which can transmit large amounts of data over long distances using high-bandwidth optical fibers. Bidirectional data transmission can be achieved by constructing fiber pairs within an optical cable and transmitting one or more channels (e.g., wavelength division multiplexing channels) per fiber pair.

[0012] As shown in the figure, the optical communication system 101 may also include terminals 103 and 105 connected via two unidirectional optical paths 111 and 121, which together form a bidirectional fiber pair. Optical path 111 can transmit information in one direction (e.g., to the right) from the transmitter 113 at terminal 103 to the receiver 115 at terminal 105. Optical path 121 can transmit information in the other direction (e.g., to the left) from the transmitter 125 at terminal 105 to the receiver 123 at terminal 103.

[0013] With respect to terminal 103, optical path 111 is the outbound path and optical path 121 is the inbound path. Optical path 111 may include optical fibers 117-1 to 117-n and optical amplifiers 119-1 to 119-n, and optical path 121 may include optical fibers 127-1 to 127-n and optical amplifiers 129-1 to 129-n. One or more of the optical amplifiers 119-1 to 119-n and 129-1 to 129-n may be EDFAs. In some examples, it can be understood that transmitter 113 and receiver 123 may be housed at terminal 103 as transponders, and similarly, transmitter 115 and receiver 125 may be housed at terminal 105 as transponders.

[0014] An optical path pair (e.g., optical paths 111, 121) can be configured as a set of amplifier pairs 119-1 to 119-n and 129-1 to 129-n within repeaters 131-1 to 131-n, and these repeaters are connected by fiber pairs 117-1 to 117-n and 127-1 to 127-n, which may be included in an optical fiber cable along with optical fibers supporting additional path pairs. Each repeater 131 may include amplifier pairs 119, 129 for each path pair, and may also include additional amplifiers for additional path pairs. The optical amplifiers 119, 129 can be EDFA or other rare-earth doped optical fiber amplifiers, Raman amplifiers, or semiconductor optical amplifiers (SOA). Coupled paths 133-1 to 133-n can be coupled, for example, between one or more optical paths 111, 121 within repeaters 131-1 to 131-n. As used in this invention, the term "couple" or "coupled" broadly means any connection or connecting, coupling, link or link connection, direct or indirect, or wired or wireless connection, and it should be understood that this does not necessarily mean that the coupled members or components are directly connected to each other.

[0015] While exemplary embodiments of the optical communication system 101 have been described, variations of the optical communication system 101 are also included within the scope of this disclosure. The optical communication system 101 may include, for example, more optical path pairs, more or fewer repeaters. Alternatively, the optical communication system 101 may not include any optical amplifiers, or it may include an optical pump power supply suitable for performing optical gain by Raman amplification in optical fibers connected to repeaters instead of optical amplifiers.

[0016] Furthermore, it is understood that a transmitter, receiver, transponder (including a transmitter and receiver) or any other suitable device for transmitting and receiving data may be provided with at least one memory and one or more processors (e.g., a CPU, ASIC, FPGA, any conventional processor, etc.) for executing instructions stored in memory. It is further understood that the optical path may be powered by (multiple) power conductors of an optical cable. Furthermore, multiple optical communication systems (e.g., optical communication system 101) may be interconnected via interconnection cables and branching units.

[0017] Line monitoring equipment (LME) and command response equipment (CRE) have previously been designed or configured to assume that terminal line amplifiers (TLAs) are always available for use with bright fiber pairs in the interface to wet equipment. For example, devices such as Monitor Interface Passive Device Packs (MI-PDPs) and more recent Common Optical Units (COUs) may be examples of passive optical packs that provide all optical interconnects with each fiber pair to the LME and CRE so that LME and CRE signals can access fiber pairs of (multiple) wet equipment. It should be understood that as used herein, “dark” optical fibers or (multiple) dark fiber pairs broadly mean (multiple) unused optical fibers available in an optical communication system. Conversely, it should be understood that as used herein, “bright” optical fibers or bright fiber pairs broadly mean (multiple) optical fibers in use that can actively transmit or receive data via light or optical wavelength.

[0018] In the example, for a bright fiber pair, (i) a general-purpose terminal device can be connected to the Submarine Line Terminating Equipment (SLTE) side of the MI-PDP or COU, (ii) the LME and CRE can be connected to the LME and CRE optical ports, and (iii) two terminal optical amplifiers can be connected to suitable ports on the MI-PDP or COU. For example, such an arrangement provides the desired gain for both the SLTE data channel and the inbound and outbound LME and CRE signals.

[0019] Figure 2 shows an example of an optical interconnection member 200 equipped with wet equipment. The optical interconnection member 200 may be a typical optical configuration for optical interconnection with the SLTE, LME, and CRE of wet equipment, and the terminal amplifier can provide an arbitrary gain between 14.5 and 23.5 dB. As shown in Figure 2, the first general-purpose terminal (the top terminal shown) can be coupled to the transmission or transmitter ("TX") section of the COU, and the second general-purpose terminal (the bottom terminal shown) can be coupled to the reception or receiver ("RX") section of the COU.

[0020] In some cases, when the fiber pair is dark and there is no or the general-purpose terminal amplifier is unusable, a different optical configuration may be required to achieve higher transmission power levels for LME and CRE. Figure 3 shows an optical configuration 300, which may be an example of such a configuration.

[0021] Figure 3 shows an example of an optical configuration 300 equipped with wet equipment. As shown, the configuration 300 includes at least a COU, an LME of one or more ports coupled to the COU, and a CRE of one or more ports coupled to the COU.

[0022] In an open cable system, in some cases, the conventional optical methods or configurations for establishing a general-purpose terminal device with a fiber pair by connecting the LME and CRE to the fiber pair of the wet equipment may not be desirable. It can be understood that an open cable system broadly means any system in which no terminal device is deployed in addition to the COU, LME, and CRE.

[0023] For example, a user or customer may prefer a clear demarcation point between a general-purpose SLTE device and an open-cable device (COU, MI-PDP, LME, CRE) from the device provider or manufacturer (or service provider). A user or customer may not want to route optical fibers back and forth between bracket matrices (bay line-ups) that can exist at different terminal station locations. Furthermore, a user or customer may not want to modify the initial dark optical fiber configuration to obtain a bright optical fiber configuration, or change the configuration for specific LME measurements (e.g., optical time-domain reflectometer (OTDR) measurements).

[0024] A clear demarcation proposal may involve deploying open-cable devices (COU, MI-PDP, LME, CRE) to the main terminal circuit amplifier and drawing a clear demarcation point (or MI PDP) on the SLTE side of the COU, or, if general-purpose terminal device amplifiers are not used, finding a way for the LME and CRE to access the fiber pair (e.g., via a coupler closer to the wet equipment).

[0025] This specification describes a new concept that better manages differences in power levels that may or may exist when a general-purpose terminal amplifier provided by the user or customer is not used, by performing a redesign of the LME and CRE with a different set of optical elements at the interface of the wet instrument.

[0026] In various embodiments, the interface device may comprise a plurality of fiber interface modules (FIMs), which are coupled to corresponding fiber pairs in a submarine optical communication system, and each FIM comprises a pair of normally closed switches. In various additional embodiments, in addition to the interface device, the optical communication system may comprise a line monitoring device for receiving EDFAs and a CRE for transmitting EDFAs, as will be described in detail below.

[0027] A new concept for connecting improved LMEs and CREs to each open cable fiber pair is shown in, and will be discussed in, the following drawings. The interface module described herein retains all the necessary functions of the CRE and LME while advantageously solving one of the larger problems that exist when performing OTDR measurements when the fiber pair is lit.

[0028] Figure 4A shows an example of an open cable fiber pair (FP) line interface module (FIM) in one or more embodiments. As will be further described below, the open cable FP line interface module, referred to as interface module 400, may be one of 12 or more fiber pair interface modules contained in or provided with a motorized cage. In the FP line interface module according to the embodiment of Figure 4A, the transmitting unit includes line LME Tx lines, LTE Tx lines, and CRE Tx lines, and the receiving unit includes line LME Rx lines, LTE Rx lines, and CRE Rx This includes the circuits, each of which is connected to a corresponding port (not individually shown), such as the CRE TX port, LME receive (Rx) port, etc.

[0029] In the embodiment, each module may be capable of serving one fiber pair and may include two reliable normally closed switches (indicated as SW1 and SW2), as shown. Switch SW1 is coupled to the LME TX line, and switch SW2 is coupled to the LTE TX line. Circulators CR1 and CR2 may be provided, as shown. A receiving coupler (i.e., CRE TX coupler CP1) is coupled to switch SW1 and LME TX coupler CP2. The provided switching capability is adapted to at least the reconfiguration of dark and bright fiber pairs, and when the fiber pair is lit using a general-purpose SLTE device, it is used to perform unserviced OTDR measurements using the optimal LME-generated load spectrum.

[0030] At least two switches must enable load management in at least dark fiber optic configurations, and in such dark fiber optic configurations, output loss of wet equipment must be minimized. If the customer or user connects a general-purpose terminal device (which also eliminates the need to load the LME), the module may be switched to connect the LME to the wet equipment via a coupler (e.g., a 10dB coupler).

[0031] Since the LME and CRE can be redesigned in interface module 400, changes to the optical jumpers are unnecessary. Furthermore, there are no optical fiber jumpers running back and forth from the interface optical elements and general-purpose terminal amplifier. Therefore, as shown in Figure 4A, a single demarcation point exists.

[0032] In the alternative example, it can be seen that the alternative configuration can reduce insertion loss in the LTE TX outbound path by positioning the CRE TX coupler between the circulator and the outbound LME TX coupler.

[0033] For example, if a cable break occurs in a bright fiber pair, the optical switch in the interface module 400 can automatically switch off to block traffic (e.g., LTE traffic), allowing the LME to provide an optimal load power spectrum for unserviced OTDR measurements. Thus, advantageously, the user or customer does not need to reconfigure the optical fiber for any LME measurement using the interface module 400.

[0034] Figures 4B and 4C show another example of an open cable fiber pair line interface module (shown as interface module 420 and interface module 440) according to one or more embodiments. As shown, various components and / or parts of interface module 420 and interface module 440 may be configured or designed differently from interface module 400 in Figure 4A, while still achieving similar effects or functions. As further shown, interface modules 420 and interface module 440 may have or include at least two switches, similar to interface module 400. In the embodiment of Figure 4B, in addition to circulators CR1 and CR2, circulator CR3 is provided on the CRE Tx line and directly connected to coupler CP1. In the embodiment of Figure 4C, in addition to circulators CR1, CR2 and CR3, coupler CP3 is provided between circulators CR2 and CR3 and coupler CP1. It should be understood that various other configurations are possible, such as the internal components of interface modules 420 and 440, and that the design or configuration shown in Figures 4B and 4C is not limited to those shown.

[0035] Furthermore, according to the embodiment, the FIM module described above may be implemented in an optical communication system if the terminal line amplifier is removed. For example, in the case of a G4 LME, a second "receive" amplifier (e.g., EDFA) may be added after the LME RX port selector switch to overcome a lack of RX power (e.g., due to the lack of an RX TLA). Similarly, in the case of a CRE, a "transmit" amplifier (e.g., EDFA) may be added to increase the power of the TX signal. Figure 4D provides such a configuration according to an embodiment of the present disclosure, and the interface module in Figure 4A is interface module 460, in which a receive amplifier (indicated as line LME Rx), e.g., EDFA (indicated as LMEA), coupled between the LME receive port (not shown, but located on the left side of the figure) and the LME receive coupler in the receiving section is added. Similarly, the CRE Tx line is coupled to a transmit amplifier or EDFA (indicated as CREA).

[0036] In additional embodiments of this disclosure, additional amplification or gain can be provided within or in conjunction with the fiber interface module. In some embodiments, alternative configurations address cases where more Rx-side gain is required to return LME or CRE signals by adding Rx-side gain to CRE Rx and LME Rx. When an Rx EDFA is added to the CRE Rx path, a receiving filter (shown as a single-channel CRE Rx filter) may be configured after the inbound CRE Rx EDFA. Figure 4E shows one variation of this latter embodiment, where a line interface module of an open cable fiber pair (FP), shown as interface module 480, is configured as follows: The optical fiber leaves interface module 480 and is coupled to a CRE Rx EDFA, then the optical fiber returns from the CRE Rx EDFA to interface module 480 via a single-channel CRE filter, and then the optical fiber leaves interface module 480 to reach the CRE Rx connector.

[0037] Figure 5 shows an example of an electric cage or electric shelf 500 for multiple FP line interface modules or fiber interface modules (FIMs) in one or more embodiments. For example, each interface module may be configured similarly to interface module 400 in Figure 4A, interface module 420 in Figure 4B, and / or line interface module 440 for open cable FP in Figure 4C.

[0038] As shown, Figure 5 illustrates the physical implementation of FIM by configuring a 19-inch wide cage with three or four rack units (RUs) of height for mounting on a standard 19-inch bracket, for example. The shelves are energizable and the switches operate with minimal power, so they do not dissipate a large amount of heat while energized.

[0039] Furthermore, fans may not be necessary. Moreover, the modularization of the motorized cage or shelf 500 allows for the deployment of a single FIM according to user / customer needs, or the swapping out of all fiber pairs without removing them in the event of a single FIM failure.

[0040] In another embodiment, the FIM may include a small backplane electrical connector that enables connection of power and control pins. Furthermore, the hot-swappable power module may be used with a cage or shelf 500, embedded with the cage or shelf, or embedded in the cage or shelf, as shown on the right side of Figure 5 (shown as a swappable control module). It should be understood that the configuration in Figure 5 is not limiting, and other physical package concepts, configurations, designs, etc., can be considered.

[0041] It should be understood that the above embodiments and examples that can be implemented or included in optical communication systems can be arranged in a variety of different configurations and are not limited to any particular configuration or any other configuration.

[0042] This specification discloses novel and inventive technology for terminal line interface modules for accessing submarine open cable systems. This disclosure is not limited in scope by the specific embodiments described herein. In practice, various other embodiments and improvements of this disclosure, in addition to those described herein, will be apparent to those skilled in the art from the above description and drawings. In particular, these embodiments may specifically include, one or more of the embodiments, features, examples, descriptions, devices, modules, methods, systems, components of optical communication systems, at least one controller, at least one processor, at least one controller circuit system, and / or at least one non-temporary computer-readable medium, etc., as described above and in the drawings.

[0043] Therefore, other such embodiments and improvements are included within the scope of this disclosure. Furthermore, while this specification has described this disclosure in the context of specific embodiments for specific purposes in specific environments, those skilled in the art will recognize that the usefulness is not limited thereto and that the invention can be beneficially implemented for any number of purposes in any number of environments. Accordingly, the claims set forth below should be construed in accordance with the entire scope and spirit of this disclosure as set forth herein. [Item 1] Equipped with multiple fiber interface modules (FIMs), The FIM comprises a receiving unit and a transmitting unit. The aforementioned transmitting unit is equipped with two normally closed switches, Of the two normally closed switches, the first switch is connected to the line monitoring device TX port (LME TX port), and the second switch is connected to the line termination device TX port (LTE TX port). A device for managing optical submarine communication systems. [Item 2] A receiving amplifier is coupled between the LME receiving port and the LME receiving coupler in the receiving unit, The transmission unit further comprises a transmission amplifier coupled to the command response device port (CRE port) of the transmission unit. The device described in item 1. [Item 3] The system further comprises a CRE TX coupler coupled to the aforementioned second switch and also coupled to the LME TX coupler, The device described in item 1 or 2. [Item 4] The system further comprises a first circulator and a second circulator coupled to the opposite side of the first switch, and a third circulator coupled between the CRE TX coupler and the CRE TX port. The device described in item 3. [Item 5] The system further comprises a third coupler provided between the second circulator, the third circulator, and the CRE TX coupler. The device described in item 4. [Item 6] It also includes at least one hot-swappable power module, The apparatus described in any one of items 1 through 5. [Item 7] The system comprises a wet-type apparatus and an interface module assembly coupled to the wet-type apparatus. The interface module assembly comprises a plurality of fiber interface modules (FIMs), The FIM comprises a receiving unit and a transmitting unit. The aforementioned transmitting unit is equipped with two normally closed switches, Of the two normally closed switches, the first switch is connected to the line monitoring device TX port (LME TX port), and the second switch is connected to the line termination device TX port (LTE TX port). Submarine communication system. [Item 8] A receiving amplifier is coupled between the LME receiving port and the LME receiving coupler in the receiving unit, The transmission unit further comprises a transmission amplifier coupled to the command response device TX port (CRE TX port) in the transmission unit. The underwater communication system described in item 7. [Item 9] The system further comprises a CRE TX coupler coupled to the aforementioned second switch and also coupled to the LME TX coupler, Submarine communication systems as described in item 7 or 8. [Item 10] The system further comprises a first circulator and a second circulator coupled to the opposite side of the first switch, and a third circulator coupled between the CRE TX coupler and the CRE TX port. The underwater communication system described in item 8. [Item 11] It further includes a third coupler located between the second circulator, the third circulator, and the CRE TX coupler. The underwater communication system described in item 10. [Item 12] The interface module assembly comprises at least one hot-swappable power supply module. The underwater communication system described in item 7. [Item 13] The system comprises a wet-type apparatus and an interface module assembly coupled to the wet-type apparatus. The interface module assembly comprises a plurality of fiber interface modules (FIMs), The FIM comprises a receiving unit, a transmitting unit, and at least one amplifier coupled between the ports of the FIM. The aforementioned transmitting unit is equipped with two normally closed switches, Of the two normally closed switches, the first switch is connected to the line monitoring device TX port (LME TX port), and the second switch is connected to the line termination device TX port (LTE TX port). Submarine communication system. [Item 14] The at least one amplifier is The receiving unit is equipped with a receiving amplifier coupled between the LME receiving port and the LME receiving coupler, The transmission unit further comprises a transmission amplifier coupled to the command response device port (CRE port) in the transmission unit. The underwater communication system described in item 13. [Item 15] The at least one amplifier comprises a CRE Rx EDFA coupled between the receiving coupler and the receiving filter in the receiving section. Submarine communication systems as described in item 13 or 14.

Claims

1. Equipped with multiple fiber interface modules (FIMs), The aforementioned FIM is, A receiving unit including an LME RX line for transmitting signals to a Line Monitoring Equipment (LME), an LTE RX line for transmitting signals to a Line Termination Equipment (LTE), a CRE RX line for transmitting signals to a Command Response Equipment (CRE), an LME RX port connected to the LME RX line for outputting signals to the LME, an LTE RX port connected to the LTE RX line for outputting signals to the LTE, a CRE RX port connected to the CRE RX line for outputting signals to the CRE, an input unit for receiving signals from wet equipment, and an input line for transmitting signals from the input unit. The system comprises an LME TX line for transmitting signals from the LME, an LTE TX line for transmitting signals from the LTE, a CRE TX line for transmitting signals from the CRE, an LME TX port connected to the LME TX line for inputting signals from the LME, an LTE TX port connected to the LTE TX line for inputting signals from the LTE, a CRE TX port connected to the CRE TX line for inputting signals from the CRE, an output unit for outputting signals to the wet equipment, and an output line for transmitting signals to the output unit. The transmitting unit further comprises a first switch and a second switch, which are normally closed switches in a 1x2 configuration. The first switch has a common terminal connected to the LME TX line, a first terminal connected to the output section, and a second terminal connected to the second switch. The second switch has a common terminal connected to the output section, a first terminal connected to the LTE TX line, and a second terminal connected to the first switch. A device for managing optical submarine communication systems.

2. The receiving unit further comprises a 2x2 LME receiving coupler and a receiving amplifier. The two ports on the first side of the LME receiving coupler are coupled to the CRE RX port and the LME RX port, respectively, and one of the two ports on the second side of the LME receiving coupler is coupled to the input section. The receiving amplifier is coupled between the LME RX port and the LME receiving coupler. The transmitting unit further comprises a transmitting amplifier coupled to the CRETX port. The apparatus according to claim 1.

3. The transmitting unit further comprises a CRE TX coupler and an LME TX coupler in a 2x2 configuration, The two ports on the first side of the CRE TX coupler are coupled to the CRE TX port and the second switch, respectively, and one of the two ports on the second side of the CRE TX coupler is coupled to the LME TX coupler. The two ports on the first side of the LME TX coupler are coupled to the CRE TX coupler and the first switch, respectively, and one of the two ports on the second side of the LME TX coupler is coupled to the output section. The apparatus according to claim 1 or 2.

4. The system further comprises a first circulator coupled to the common terminal of the first switch, a second circulator coupled between the first switch and the LME TX coupler, and a third circulator coupled between the CRE TX coupler and the CRE TX port. The apparatus according to claim 3.

5. Further comprising a third coupler in a 2x2 configuration, The two ports on the first side of the third coupler are coupled to the second circulator and the third circulator, respectively, and one of the two ports on the second side of the third coupler is coupled to the CRE TX coupler. The apparatus according to claim 4.

6. It further includes at least one hot-swappable power module, The apparatus according to any one of claims 1 to 5.

7. The system comprises a wet-type apparatus and an interface module assembly coupled to the wet-type apparatus. The interface module assembly comprises a plurality of fiber interface modules (FIMs), The aforementioned FIM is, A receiving unit including an LME RX line for transmitting signals to a Line Monitoring Equipment (LME), an LTE RX line for transmitting signals to a Line Termination Equipment (LTE), a CRE RX line for transmitting signals to a Command Response Equipment (CRE), an LME RX port connected to the LME RX line for outputting signals to the LME, an LTE RX port connected to the LTE RX line for outputting signals to the LTE, a CRE RX port connected to the CRE RX line for outputting signals to the CRE, an input unit for receiving signals from wet equipment, and an input line for transmitting signals from the input unit. The system comprises an LME TX line for transmitting signals from the LME, an LTE TX line for transmitting signals from the LTE, a CRE TX line for transmitting signals from the CRE, an LME TX port connected to the LME TX line for inputting signals from the LME, an LTE TX port connected to the LTE TX line for inputting signals from the LTE, a CRE TX port connected to the CRE TX line for inputting signals from the CRE, an output unit for outputting signals to the wet equipment, and an output line for transmitting signals to the output unit. The transmitting unit further comprises a first switch and a second switch, which are two normally closed switches with a 1x2 configuration. The first switch has a common terminal connected to the LME TX line, a first terminal connected to the output section, and a second terminal connected to the second switch. The second switch has a common terminal connected to the output section, a first terminal connected to the LTE TX line, and a second terminal connected to the first switch. Submarine communication system.

8. The receiving unit further comprises a 2x2 configuration LME receiving coupler and a receiving amplifier. The two ports on the first side of the LME receiving coupler are coupled to the CRE RX port and the LME RX port, respectively, and one of the two ports on the second side of the LME receiving coupler is coupled to the input section. The receiving amplifier is coupled between the LME RX port and the LME receiving coupler. The transmitting unit further comprises a transmitting amplifier coupled to the CRE TX port. The submarine communication system according to claim 7.

9. The transmitting unit further comprises a CRE TX coupler and an LME TX coupler in a 2x2 configuration, The two ports on the first side of the CRE TX coupler are coupled to the CRE TX port and the second switch, respectively, and one of the two ports on the second side of the CRE TX coupler is coupled to the LME TX coupler. The two ports on the first side of the LME TX coupler are coupled to the CRE TX coupler and the first switch, respectively, and one of the two ports on the second side of the LME TX coupler is coupled to the output section. The submarine communication system according to claim 7 or 8.

10. The system further comprises a first circulator coupled to the common terminal of the first switch, a second circulator coupled between the first switch and the LME TX coupler, and a third circulator coupled between the CRE TX coupler and the CRE TX port. The submarine communication system according to claim 9.

11. Further comprising a third coupler in a 2x2 configuration, The two ports on the first side of the third coupler are coupled to the second circulator and the third circulator, respectively, and one of the two ports on the second side of the third coupler is coupled to the CRE TX coupler. The submarine communication system according to claim 10.

12. The interface module assembly comprises at least one hot-swappable power supply module. The submarine communication system according to any one of claims 7 to 11.

13. The system comprises a wet-type apparatus and an interface module assembly coupled to the wet-type apparatus. The interface module assembly comprises a plurality of fiber interface modules (FIMs), The aforementioned FIM is, A receiving unit including an LME RX line for transmitting signals to a Line Monitoring Equipment (LME), an LTE RX line for transmitting signals to a Line Termination Equipment (LTE), a CRE RX line for transmitting signals to a Command Response Equipment (CRE), an LME RX port connected to the LME RX line for outputting signals to the LME, an LTE RX port connected to the LTE RX line for outputting signals to the LTE, a CRE RX port connected to the CRE RX line for outputting signals to the CRE, an input unit for receiving signals from the wet equipment, and an input line for transmitting signals from the input unit. A transmitting unit including an LME TX line for transmitting signals from the LME, an LTE TX line for transmitting signals from the LTE, a CRE TX line for transmitting signals from the CRE, an LME TX port connected to the LME TX line for inputting signals from the LME, an LTE TX port connected to the LTE TX line for inputting signals from the LTE, a CRE TX port connected to the CRE TX line for inputting signals from the CRE, an output unit for outputting signals to the wet equipment, and an output line for transmitting signals to the output unit. The FIM comprises at least one amplifier coupled to a port, The transmitting unit further comprises a first switch and a second switch, which are two normally closed switches with a 1x2 configuration. The first switch has a common terminal connected to the LME TX line, a first terminal connected to the output section, and a second terminal connected to the second switch. The second switch has a common terminal connected to the output section, a first terminal connected to the LTE TX line, and a second terminal connected to the first switch. Submarine communication system.

14. The receiving unit further comprises a 2x2 LME receiving coupler, The two ports on the first side of the LME receiving coupler are coupled to the CRE RX port and the LME RX port, respectively, and one of the two ports on the second side of the LME receiving coupler is coupled to the input section. The at least one amplifier is The system includes a receiving amplifier coupled between the LME RX port and the LME receiving coupler, The system further comprises a transmit amplifier coupled to the aforementioned CRETX port. The submarine communication system according to claim 13.

15. The at least one amplifier comprises a receiving filter coupled to the CRE RX port and a CRE Rx EDFA coupled between the LME receiving coupler and the receiving filter. The submarine communication system according to claim 14.

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