Dual fiber to single fiber device and optical communication system

Abstract

The application provides a dual-fiber to single-fiber device and an optical communication system, and belongs to the technical field of optical communication. The dual-fiber to single-fiber device comprises a device main body, a bidirectional optical fiber, a transmitting optical fiber and a receiving optical fiber. The inside of the device main body is provided with a filter, one end of the bidirectional optical fiber, the transmitting optical fiber and the receiving optical fiber extends into the inside of the device main body, and the other end is located outside the device main body. The filter is used for transmitting or reflecting the light beam received from the receiving optical fiber to the bidirectional optical fiber, and the filter is also used for transmitting or reflecting the light beam received from the bidirectional optical fiber to the transmitting optical fiber. When the dual-fiber to single-fiber device is applied to the optical communication system, the transmitting optical fiber and the receiving optical fiber of the dual-fiber to single-fiber device are connected to the receiving port and the transmitting port of the remote optical module respectively, and the bidirectional optical fiber of the dual-fiber to single-fiber device is used for connecting a splitting and combining device. Thus, the two optical fibers required between the remote optical module and the splitting and combining device are converted into one bidirectional optical fiber.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a dual-fiber to single-fiber device and an optical communication system. Background Technology

[0002] Currently, optical communication has been widely used in various scenarios. For example, in fiber-to-the-home (FTTH) scenarios, optical fibers are laid into rooms on various floors of a campus to transmit uplink and downlink information between access devices in the rooms and the central switch in the campus.

[0003] The optical communication system includes a central optical module, a splitter / combiner, and multiple remote optical modules. The central optical module is plugged into a central switch and connected to the splitter / combiner via optical fiber. The splitter / combiner includes multiple transmit ports and multiple receive ports. The transmit ports of the splitter / combiner are connected to the receive ports of the multiple remote optical modules via optical fiber, and the receive ports of the splitter / combiner are connected to the transmit ports of the multiple remote optical modules via optical fiber. The remote optical modules are inserted into or integrated into the access equipment.

[0004] In the aforementioned optical communication system, each remote optical module needs to be connected to the transmitting and receiving ports of the optical splitter / combiner via two optical fibers. Furthermore, the distance between the remote optical module and the optical splitter / combiner is generally quite large, resulting in the considerable length of these two optical fibers. This not only wastes optical fiber resources but also makes it inconvenient to arrange optical fibers between the remote optical module and the optical splitter / combiner. Utility Model Content

[0005] This application provides a two-fiber to one-fiber device and an optical communication system. The two-fiber to one-fiber device can convert the two optical fibers required between the remote optical module and the optical splitter / combiner into one optical fiber. The technical solutions of the two-fiber to one-fiber device and the optical communication system are described below.

[0006] In a first aspect, this application provides a dual-fiber to single-fiber device. The dual-fiber to single-fiber device includes a device body, a bidirectional optical fiber, a transmitting optical fiber, and a receiving optical fiber. A filter is disposed inside the device body. One end of each of the bidirectional optical fiber, the transmitting optical fiber, and the receiving optical fiber extends into the device body, while the other end is located outside the device body. The filter is used to transmit a light beam received from the receiving optical fiber to the bidirectional optical fiber. The filter is located on the outgoing optical path of the receiving optical fiber, and the bidirectional optical fiber is located on the first outgoing optical path of the filter. The first outgoing optical path is either a reflection path or a transmission path. The filter is also used to transmit a light beam received from the bidirectional optical fiber to the transmitting optical fiber. The filter is located on the outgoing optical path of the bidirectional optical fiber, and the transmitting optical fiber is located on the second outgoing optical path of the filter. The second outgoing optical path is either a reflection path or a transmission path.

[0007] The technical solution provided in this application, when a dual-fiber to single-fiber device is applied in an optical communication system, connects the transmitting and receiving fibers of the dual-fiber to single-fiber device to the receiving and transmitting ports of the remote optical module, respectively, and uses the bidirectional fiber of the dual-fiber to single-fiber device to connect to a splitter / combiner. In the downlink direction, the dual-fiber to single-fiber device receives the downlink beam transmitted by the splitter / combiner through the bidirectional fiber and transmits the downlink beam to the receiving port of the remote optical module through the transmitting fiber. In the uplink direction, the dual-fiber to single-fiber device receives the uplink beam transmitted by the transmitting port of the remote optical module through the receiving fiber and transmits the uplink beam to the splitter / combiner through the bidirectional fiber.

[0008] As can be seen, by applying the dual-fiber to single-fiber device provided in this application in the optical communication system, the two optical fibers required between the remote optical module and the optical splitter / combiner are converted into one optical fiber (i.e., bidirectional optical fiber), saving optical fiber resources and facilitating the arrangement of optical fibers between the remote optical module and the optical splitter / combiner. Furthermore, the remote optical module and the optical splitter / combiner can still transmit optical signals normally.

[0009] In one implementation, the device body includes two oppositely positioned ends, with a transmitting optical fiber and a receiving optical fiber extending from each end of the device body. A first outgoing optical path is a reflected optical path, a second outgoing optical path is a transmitted optical path, and the bidirectional optical fiber and the receiving optical fiber extend from the same end of the device body; alternatively, the first outgoing optical path is a transmitted optical path, the second outgoing optical path is a reflected optical path, and the bidirectional optical fiber and the transmitting optical fiber extend from the same end of the device body. Since one of the first and second outgoing optical paths is a transmitted optical path and the other a reflected optical path, having the transmitting and receiving optical fibers extend from opposite ends of the device body simplifies the internal structure of the device body and reduces the number of lenses included in the device body.

[0010] In one implementation, the dual-fiber to single-fiber device further includes a housing. The main body of the device is located inside the housing, and the housing contains at least one fiber coil. The transmitting or receiving fiber is coiled in at least one fiber coil, and the transmitting and receiving fibers extend from the same side wall of the housing.

[0011] The technical solution provided in this application allows the transmitting and receiving optical fibers to extend from the same side wall of the housing, eliminating the need for bending the portions of the fibers outside the housing before they can be connected to the transmitting and receiving ports of the same optical module. Furthermore, the presence of a fiber coil inside the housing allows any bent transmitting or receiving fibers to be coiled within the coil, thus preventing excessively small bending radii.

[0012] In one implementation, the device body includes two oppositely positioned ends, with a transmitting optical fiber and a receiving optical fiber extending from the same end of the device body, and a bidirectional optical fiber extending from the other end of the device body. This allows the transmitting and receiving optical fibers to be connected to the transmitting and receiving ports of the same remote optical module without bending.

[0013] In one implementation, at least one steering mirror is also provided inside the device body. The first outgoing optical path is a reflected optical path, the second outgoing optical path is a transmitted optical path, and at least one steering mirror is located on the optical path between the receiving optical fiber and the filter, used to redirect the light beam transmitted by the receiving optical fiber towards the filter. Alternatively, the first outgoing optical path is a transmitted optical path, the second outgoing optical path is a reflected optical path, and at least one steering mirror is located on the optical path between the filter and the transmitting optical fiber, used to redirect the light beam reflected from the filter towards the transmitting optical fiber. The steering mirror redirects the light beam inside the device body, facilitating the transmission and receiving optical fibers to extend from the same end of the device body.

[0014] In one implementation, the incident light beam is perpendicular to the filter, and the number of deflecting mirrors is at least two. The at least two deflecting mirrors are used to deflect the light beam transmitted by the receiving fiber by 180° before transmitting it to the filter, or to deflect the light beam reflected by the filter by 180° before transmitting it to the transmitting fiber.

[0015] In one implementation, the light beam incident on the filter is not perpendicular to the filter. The first outgoing optical path is a reflected optical path, the second outgoing optical path is a transmitted optical path, and at least one steering mirror and the filter are used to deflect the light beam transmitted by the receiving fiber and exit from the filter, wherein the light beam transmitted by the receiving fiber and the light beam exiting from the filter are parallel and have the same propagation direction; or, the first outgoing optical path is a transmitted optical path, the second outgoing optical path is a reflected optical path, and the filter and at least one steering mirror are used to deflect the light beam transmitted bidirectionally and exit from at least one steering mirror, wherein the light beam transmitted by the bidirectional fiber and the light beam exiting from at least one steering mirror are parallel and have the same propagation direction.

[0016] In one implementation, the transmitting optical fiber has a first optical fiber connector at its external end, which is used to connect to the receiving port of the optical module. The receiving optical fiber has a second optical fiber connector at its external end, which is used to connect to the transmitting port of the optical module. This facilitates the connection of the transmitting and receiving optical fibers to the optical module.

[0017] In one implementation, the end of the bidirectional optical fiber located outside the device body is used to connect the extension optical fiber via thermal fusion splicing. The bidirectional-to-single-fiber device also includes a housing, inside which is a heat-shrink tubing retaining structure. This structure secures the heat-shrink tubing, which is used to loop around the thermal fusion splice portion of the bidirectional and extension optical fibers. Thus, the housing and heat-shrink tubing protect the thermal fusion splice portion.

[0018] In one implementation, the heat shrink tubing limiting structure includes two first plates, which are fixed to the bottom wall of a housing and arranged opposite to each other. A first limiting groove is formed between the two first plates to accommodate the heat shrink tubing. The heat shrink tubing is clamped between the two first plates.

[0019] In one implementation, the first plate includes a first intermediate section and two first side sections located on either side of the first intermediate section. The first intermediate section connects to the bottom wall of the box, and the bottom wall has first openings corresponding to the two first side sections, so that the two first side sections are suspended. In this way, the first side sections have greater elasticity and can better clamp the heat shrink tubing.

[0020] In one implementation, the inside of the box is also provided with a device body limiting structure, which is used to fix the device body.

[0021] In one implementation, the device body limiting structure includes two second plates, which are fixed to the bottom wall of the housing and arranged opposite to each other. A second limiting groove is formed between the two second plates to accommodate the device body. The device body is clamped between the two second plates.

[0022] In one implementation, the second plate includes a second intermediate section and two second side sections located on either side of the second intermediate section. The second intermediate section connects to the bottom wall of the housing, and the bottom wall has second openings corresponding to the two second side sections, allowing the two second side sections to be suspended. This provides greater elasticity to the second side sections, enabling them to better clamp the main body of the device.

[0023] In one implementation, the interior of the housing also includes at least one fiber coil, on which bidirectional optical fibers and / or extension optical fibers are coiled. This facilitates the arrangement and positioning of the optical fibers.

[0024] In one implementation, the housing includes two opposing first sidewalls. A transmitting or receiving optical fiber is coiled in at least one fiber optic coil, and both the transmitting and receiving optical fibers extend from the same first sidewall. An extension optical fiber extends from the other first sidewall. This facilitates the connection of the transmitting and receiving optical fibers to the receiving and transmitting ports of the same optical module, and also facilitates the connection of the extension optical fiber to a splitter / combiner or other dual-fiber to single-fiber devices.

[0025] In one implementation, the two first sidewalls are respectively positioned opposite to both ends of the device body and also opposite to both ends of the heat-shrink tubing. This facilitates the arrangement of optical fibers.

[0026] In one implementation, multiple fiber coils are arranged along the direction of the two first sidewalls and positioned between the device body limiting structure and the heat-shrinkable tubing limiting structure. Along the direction of the two first sidewalls, the two fiber coils at the ends are closer to the first sidewalls than the device body limiting structure and the heat-shrinkable tubing limiting structure. This facilitates the winding of the optical fiber while simultaneously fixing the device body and the heat-shrinkable tubing.

[0027] In one implementation, three fiber optic coils are used, with the outer diameter of the middle coil being smaller than that of the two coils at the ends. This prevents the middle coil from being too close to the device body limiting structure and heat shrink tubing limiting structure on both sides, which could prevent fiber coiling from becoming impossible.

[0028] In one implementation, a third fiber optic connector is provided at one end of the bidirectional optical fiber located outside the device body. This third fiber optic connector is used to connect and extend the optical fiber via an adapter.

[0029] In one implementation, the first outgoing optical path is a transmission optical path, the second outgoing optical path is a reflection optical path, and the reflection band of the filter covers multiple wavelength division multiplexer (WDM) bands. Alternatively, the first outgoing optical path is a reflection optical path, the second outgoing optical path is a transmission optical path, and the transmission band of the filter covers multiple WDM wavelengths.

[0030] In one implementation, the first outgoing optical path is a transmission optical path, and the second outgoing optical path is a reflection optical path, with the filter's reflection band covering only one WDM wavelength. Alternatively, the first outgoing optical path is a reflection optical path, and the second outgoing optical path is a transmission optical path, with the filter's transmission band covering only one WDM wavelength. In this way, the filter can filter out the corresponding WDM wavelength beam from a received beam that includes multiple WDM wavelengths.

[0031] Secondly, this application provides an optical communication system. The optical communication system includes a central optical module, a splitter / combiner, multiple remote optical modules, and multiple dual-fiber to single-fiber devices as described in any of the first aspects. The central optical module is connected to the splitter / combiner, which includes multiple ports, each port being connected to a bidirectional optical fiber of one of the multiple dual-fiber to single-fiber devices. The transmitting optical fibers of the multiple dual-fiber to single-fiber devices are respectively connected to the receiving ports of the multiple remote optical modules, and the receiving optical fibers of the multiple dual-fiber to single-fiber devices are respectively connected to the transmitting ports of the multiple remote optical modules.

[0032] In the technical solution provided in this application, the dual-fiber to single-fiber device converts the two optical fibers required between each remote optical module and the optical splitter / combiner into one optical fiber, that is, the bidirectional optical fiber of the dual-fiber to single-fiber device, which saves optical fiber resources and is beneficial for arranging optical fibers between the remote optical module and the optical splitter / combiner.

[0033] In one implementation, in the downlink direction, a central optical module transmits a first downlink beam to a splitter / combiner. The splitter / combiner divides the first downlink beam into multiple second downlink beams and transmits these multiple second downlink beams through multiple ports. Each dual-fiber to single-fiber device receives the second downlink beams via bidirectional optical fiber and transmits them via a transmitting optical fiber. Each remote optical module filters out a beam of the corresponding downlink wavelength from the second downlink beams, wherein different remote optical modules correspond to different downlink wavelengths.

[0034] In the uplink direction, each remote optical module is used to transmit a first uplink beam. Each dual-fiber to single-fiber device is used to receive the first uplink beam through a receiving fiber and transmit the first uplink beam through a bidirectional fiber. A splitter / combiner is used to receive multiple first uplink beams through multiple ports, combine the multiple first uplink beams into a second uplink beam, and transmit the second uplink beam to the central optical module.

[0035] In one implementation, in the downlink direction, a central optical module transmits a first downlink beam to a splitter / combiner. The splitter / combiner splits the first downlink beam into multiple second downlink beams, which are then transmitted through multiple ports. Each dual-fiber to single-fiber device receives the second downlink beams via bidirectional optical fiber. A filter on each dual-fiber to single-fiber device filters out the corresponding downlink wavelength from the second downlink beams and transmits it to the corresponding remote optical module via a transmitting optical fiber. Different dual-fiber to single-fiber devices correspond to different downlink wavelengths.

[0036] In the uplink direction, each remote optical module is used to transmit a first uplink beam. Each dual-fiber to single-fiber device is used to receive the first uplink beam through a receiving fiber and transmit the first uplink beam through a bidirectional fiber. A splitter / combiner is used to receive multiple first uplink beams through multiple ports, combine the multiple first uplink beams into a second uplink beam, and transmit the second uplink beam to the central optical module.

[0037] Thirdly, this application provides another optical communication system. The optical communication system includes a central optical module, a splitter / combiner, multiple remote optical modules, multiple first dual-fiber to single-fiber devices, and multiple second dual-fiber to single-fiber devices. The central optical module is connected to the splitter / combiner. The splitter / combiner includes multiple transmitting ports and multiple receiving ports. The multiple transmitting ports are respectively connected to the receiving optical fibers of the multiple first dual-fiber to single-fiber devices, and the multiple receiving ports are respectively connected to the transmitting optical fibers of the multiple first dual-fiber to single-fiber devices. The bidirectional optical fibers of the multiple first dual-fiber to single-fiber devices are respectively connected to the bidirectional optical fibers of the multiple second dual-fiber to single-fiber devices. The transmitting optical fibers of the multiple second dual-fiber to single-fiber devices are respectively connected to the receiving ports of the multiple remote optical modules, and the receiving optical fibers of the multiple second dual-fiber to single-fiber devices are respectively connected to the transmitting ports of the multiple remote optical modules. Wherein, the first dual-fiber to single-fiber devices and the second dual-fiber to single-fiber devices are both dual-fiber to single-fiber devices as described in the first aspect. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of an optical communication system in related technologies;

[0039] Figure 2 This is a schematic diagram of an optical communication system in related technologies;

[0040] Figure 3 This is a schematic diagram of another optical communication system in related technologies;

[0041] Figure 4 This is a schematic diagram of the first optical communication system provided in the embodiments of this application;

[0042] Figure 5 It shows Figure 4 A schematic diagram of the internal structure of the first dual-fiber to single-fiber device and the second dual-fiber to single-fiber device in the diagram.

[0043] Figure 6 This is a schematic diagram of a second optical communication system provided in an embodiment of this application;

[0044] Figure 7 It shows Figure 6 A schematic diagram of the internal structure of the dual-fiber to single-fiber device in the image;

[0045] Figure 8 This is a schematic diagram of a third optical communication system provided in the embodiments of this application;

[0046] Figure 9 yes Figure 8 A schematic diagram of the internal structure of the dual-fiber to single-fiber device in the image;

[0047] Figure 10 yes Figure 5 , Figure 7 and Figure 9The diagram shows the outline of the dual-fiber to single-fiber device;

[0048] Figure 11 This is a schematic diagram of the internal structure of another dual-fiber to single-fiber device provided in an embodiment of this application;

[0049] Figure 12 yes Figure 11 The diagram shows the outline of the dual-fiber to single-fiber device;

[0050] Figure 13 This is an outline drawing of a dual-fiber to single-fiber device provided in an embodiment of this application;

[0051] Figure 14 yes Figure 13 A schematic diagram of the internal structure of the housing of the dual-fiber to single-fiber device is shown.

[0052] Figure 15 yes Figure 13 A schematic diagram of the internal structure of the housing of the dual-fiber to single-fiber device is shown.

[0053] Figure 16 This is an outline drawing of another dual-fiber to single-fiber device provided in an embodiment of this application;

[0054] Figure 17 yes Figure 16 The diagram shows an internal structure of a dual-fiber to single-fiber device.

[0055] Figure 18 yes Figure 16 Another internal structure diagram of the dual-fiber to single-fiber device is shown in the figure;

[0056] Figure 19 yes Figure 16 Another internal structure diagram of the dual-fiber to single-fiber device is shown in the figure;

[0057] Figure 20 yes Figure 16 Another internal structure diagram of the dual-fiber to single-fiber device is shown in the figure;

[0058] Figure 21 yes Figure 16 Another internal structure diagram of the dual-fiber to single-fiber device is shown in the figure;

[0059] Figure 22 yes Figure 16 Another internal structure diagram of the dual-fiber to single-fiber device is shown in the figure;

[0060] Figure 23 This is a schematic diagram of a box body provided in an embodiment of this application;

[0061] Figure 24 This is a schematic diagram of a heat shrink tubing limiting structure provided in an embodiment of this application;

[0062] Figure 25 This is a schematic diagram of a device body limiting structure provided in an embodiment of this application;

[0063] Figure 26 This is a schematic diagram of the interior of the housing of a dual-fiber to single-fiber device provided in an embodiment of this application;

[0064] Figure 27 This is an outline drawing of a dual-fiber to single-fiber device provided in an embodiment of this application;

[0065] Figure 28 This is a schematic diagram of the interior of the housing of a dual-fiber to single-fiber device provided in an embodiment of this application;

[0066] Figure 29 This is an outline drawing of a dual-fiber to single-fiber device provided in an embodiment of this application;

[0067] Figure 30 This is an outline drawing of a dual-fiber to single-fiber device provided in an embodiment of this application.

[0068] Legend

[0069] 100. Routing and switching equipment; 200. Central optical module; 300. Optical splitter / combiner; 400. Remote optical module; 500. Dual-fiber to single-fiber device; 501. First dual-fiber to single-fiber device; 502. Second dual-fiber to single-fiber device.

[0070] 1. Device body; 10. Prism; 11. Housing; 12. Filter; 13. First fiber collimator; 14. Second fiber collimator; 15. Steering mirror; 16. Third fiber collimator; 17. First transmission plate; 18. Second transmission plate.

[0071] 2. Bidirectional optical fiber; 21. Third optical fiber connector;

[0072] 3. Transmitting optical fiber; 31. First optical fiber connector;

[0073] 4. Receiving optical fiber; 41. Second optical fiber connector;

[0074] 5. Box body; 51. Bottom shell; 510. Bottom wall; 5101. First opening; 5102. Second opening; 511. First side wall; 5111. Fiber optic hole; 512. Second side wall; 5120. Snap-fit ​​hole; 5121. Snap-fit ​​strip; 513. Device body limiting structure; 5130. Second limiting groove; 5131. Second plate; 5132. Second middle section; 5133. Second side section; 514. Fiber optic coil; 5141. Cylinder; 5142. First fiber optic strip; 515. Heat shrink tubing limiting structure; 5150. First limiting groove; 5151. First plate; 5152. First middle section; 5153. First side section; 516. Fiber optic snap-fit ​​structure; 517. Second fiber optic strip; 52. Top cover; 521. Snap-fit ​​protrusion;

[0075] 6. Heat shrink tubing;

[0076] 7. Extend the optical fiber. Detailed Implementation

[0077] Currently, optical communication has been widely used in various scenarios. For example, in fiber-to-the-home (FTTH) scenarios, optical fibers are laid into rooms on different floors of a campus to transmit uplink and downlink information between access devices in the rooms and routing and switching equipment within the campus.

[0078] Figure 1 A schematic diagram of an optical communication system in the related art is shown. For example... Figure 1 As shown, the optical communication system includes a central optical module 200, an optical splitter / combiner 300, and multiple remote optical modules 400. Figure 1 (The following explanation uses three remote optical modules, 400, as an example.) The central optical module 200 can also be called the core optical module or the local office optical module. The remote optical module 400 can also be called the access-side optical module or the terminal optical module. Figure 1 The remote optical module 400 is a dual-fiber bidirectional optical module, which refers to an optical module with a transmitting port and a receiving port. The transmitting port is dedicated to transmitting a light beam, and the receiving port is dedicated to receiving a light beam.

[0079] like Figure 1As shown, the central optical module 200 is plugged into the routing and switching device 100. Multiple remote optical modules 400 can be plugged into multiple access devices, or integrated into multiple access devices (not shown in the figure). The routing and switching device 100 can be a switch (such as a local area network switch (LSW)) or a router. The routing and switching device 100 can also be called a central switch, core switch, or other names. Access devices can be industry-standard asteroids, access points (APs), or other devices. An asteroid can also be considered a small access switch. The central optical module 200 is connected to the optical splitter / combiner 300 via optical fiber. The optical splitter / combiner 300 includes multiple transmitting ports and multiple receiving ports. The multiple transmitting ports of the optical splitter / combiner 300 (indicated by black boxes) are connected to the receiving ports of multiple remote optical modules 400 via multiple optical fibers (as shown by solid arrows). The multiple receiving ports of the optical splitter / combiner 300 (indicated by white boxes) are connected to the transmitting ports of multiple remote optical modules 400 via multiple optical fibers (as shown by dashed arrows).

[0080] Reference Figure 1 As shown by the solid arrows, in the downlink direction, the routing switching device 100 sends multiple downlink electrical signals to the central optical module 200. The central optical module 200 converts the multiple downlink electrical signals into multiple beams of different downlink wavelengths, for example, converting them into... Figure 1 The optical system comprises three downlink wavelength beams: λ1', λ2', and λ3'. The central optical module 200 combines these multiple downlink wavelength beams into a first downlink beam (e.g., beams λ1'2'3') via an output multiplexer (oMUX) and sends this first downlink beam to the optical splitter / combiner 300. The optical splitter / combiner 300 then splits the first downlink beam into multiple second downlink beams. The optical splitter / combiner 300 transmits these multiple second downlink beams to the receiving ports of multiple remote optical modules 400 via multiple transmitting ports. Each remote optical module 400 receives one of the multiple second downlink beams and extracts the corresponding downlink signal from each beam. This enables the routing switching device 100 to send downlink information to the access device.

[0081] Reference Figure 1As shown by the dashed arrows, in the uplink direction, multiple remote optical modules 400 transmit first uplink beams to the receiving port of the optical splitter / combiner 300 through their transmitting ports. Different remote optical modules 400 correspond to different uplink wavelengths. For example, remote optical module one transmits beam λ1 with an uplink wavelength of λ1, remote optical module two transmits beam λ2 with an uplink wavelength of λ2, and remote optical module three transmits beam λ3 with an uplink wavelength of λ3. The optical splitter / combiner 300 combines the multiple first uplink beams into a second uplink beam (beam λ123), which is then transmitted to the central optical module 300. This enables multiple access devices to transmit uplink information to the routing and switching device 100.

[0082] Furthermore, according to the beam splitting and combining device 300, Figure 1 Optical communication systems in China can be divided into: Figure 2 The optical communication system shown and Figure 3 The optical communication system shown below. The following sections will discuss... Figure 2 and Figure 3 The two optical communication systems shown are explained below.

[0083] Figure 2 The optical splitter / combiner 300 in the illustrated optical communication system uses wavelength division multiplexing (WDM) to split the light, that is, it splits the light according to wavelength. For example... Figure 2 As shown, the optical splitter / combiner 300 includes a splitter, a combiner, and a beam splitter. The splitter is connected to multiple transmitting ports (indicated by black boxes) of the optical splitter / combiner 300, and the combiner is connected to multiple receiving ports (indicated by white boxes) of the optical splitter / combiner 300.

[0084] Reference Figure 2 As shown by the solid arrows, in the downlink direction, the central optical module 200 sends a first downlink beam (beam λ1'2'3') to the optical splitter / combiner 300. The splitter in the optical splitter / combiner 300 receives the first downlink beam and sends it to the demultiplexer. The demultiplexer splits the first downlink beam (beam λ1'2'3') into multiple second downlink beams (such as beam λ1', beam λ2', and beam λ3'), which are then sent to the receiving ports of multiple remote optical modules 400. Different remote optical modules 400 correspond to different downlink wavelengths; for example, the downlink wavelength corresponding to remote optical module one is λ1', the downlink wavelength corresponding to remote optical module two is λ2', and the downlink wavelength corresponding to remote optical module three is λ3'.

[0085] like Figure 2 As shown, the wavelengths of the second downlink beams transmitted from different transmitting ports are different. Therefore, Figure 2The multiple remote optical modules 400 shown can only be connected to the optical splitter / combiner 300 in the order shown in the figure. That is, the positions of the three remote optical modules 400 cannot be interchanged. Otherwise, the wavelength of the second downlink beam transmitted by the transmitting port of the optical splitter / combiner 300 will be inconsistent with the downlink wavelength corresponding to the remote optical module 400, making it impossible for the remote optical module 400 to process the corresponding signal.

[0086] Reference Figure 2 As shown by the dashed arrows, in the uplink direction, multiple remote optical modules 400 respectively transmit first uplink beams (beams λ1, λ2, and λ3) to the receiving port of the optical splitter / combiner 300 through their transmitting ports. The multiple remote optical modules 400 correspond to different uplink wavelengths. The multiplexer of the optical splitter / combiner 300 combines the multiple first uplink beams into a second uplink beam (beam λ123) and transmits it to the beam splitter. The beam splitter then transmits the second uplink beam (beam λ123) to the central optical module 200.

[0087] Figure 3 The optical splitter / combiner 300 in the illustrated optical communication system uses power splitting to split the light, that is, it splits the light according to optical power. Therefore, the light beam before and after splitting by the optical splitter / combiner 300 includes the same wavelength. Figure 3 As shown, the optical splitter / combiner 300 includes a beam splitter, a beam splitter, and an optical coupler. The beam splitter is connected to multiple transmitting ports (indicated by black boxes) of the optical splitter / combiner 300, and the optical coupler is connected to multiple receiving ports (indicated by white boxes) of the optical splitter / combiner 300.

[0088] Reference Figure 3 As shown by the solid arrows, in the downlink direction, the central optical module 200 sends a first downlink beam (beam λ1'2'3') to the beam splitter 300. The beam splitter in the beam splitter 300 receives the first downlink beam and sends it to the beam splitter. The beam splitter splits the first downlink beam (beam λ1'2'3') into multiple second downlink beams (beam λ1'2'3'), sending these multiple second downlink beams to the receiving ports of multiple remote optical modules 400. Since the beam splitter uses a power splitting method, the first and second downlink beams have the same wavelength, both represented by beam λ1'2'3'. Multiple remote optical modules 400 respectively receive the multiple second downlink beams and filter out the corresponding downlink wavelength (beam λ1, beam λ2, or beam λ3) from the received second downlink beams (beam λ1'2'3'). Since the downlink wavelengths corresponding to the multiple remote optical modules 400 are different, the filters in the multiple remote optical modules 400 are different.

[0089] from Figure 3As can be seen, the second downlink beams transmitted to multiple remote optical modules 400 are all identical (all λ1'2'3'), therefore, Figure 3 The positions of the multiple remote optical modules 400 in the system can be interchanged, meaning that the remote optical modules 400 can be blindly inserted. This makes the networking of the optical communication system more flexible.

[0090] Reference Figure 3 As shown by the dashed arrows, in the uplink direction, multiple remote optical modules 400 respectively transmit first uplink beams (beams λ1, λ2, and λ3) to the receiving port of the optical splitter / combiner 300 through their transmitting ports. The multiple remote optical modules 400 correspond to different uplink wavelengths. The optical coupler of the optical splitter / combiner 300 combines the multiple first uplink beams into a second uplink beam (beams λ1, λ2, and λ3) and transmits it to the beam splitter. The beam splitter then transmits the second uplink beam to the central optical module 200.

[0091] exist Figures 1-3 In the illustrated optical communication system, each remote optical module 400 requires two optical fibers to connect to the transmitting and receiving ports of the optical splitter / combiner 300. Furthermore, the distance between the remote optical module 400 and the optical splitter / combiner 300 is generally quite large, for example, approximately 1km-2km, resulting in long optical fibers. This leads to a waste of optical fiber resources and also makes it inconvenient to arrange optical fibers between the remote optical module 400 and the optical splitter / combiner 300.

[0092] To reduce the number of optical fibers between the remote optical module 400 and the optical splitter / combiner 300, one approach is to replace the dual-fiber bidirectional optical module with a single-fiber bidirectional optical module. This way, each remote optical module 400 only needs to be connected to the optical splitter / combiner 300 via a single optical fiber. However, this requires replacing existing dual-fiber bidirectional optical modules and also necessitates the redesign and development of a new single-fiber bidirectional optical module, resulting in higher costs. A single-fiber bidirectional optical module refers to an optical module with a single bidirectional transmission port, through which it can transmit and receive light beams.

[0093] In view of the above-mentioned technical problems, embodiments of this application provide a variety of optical communication systems. These optical communication systems are equipped with a dual-fiber to single-fiber device 500. The dual-fiber to single-fiber device 500 can convert the two optical fibers between each remote optical module 400 and the optical splitter / combiner 300 into a single optical fiber, which not only reduces the number of optical fibers, but also eliminates the need to redevelop a single-fiber bidirectional optical module. The optical communication systems provided in the embodiments of this application are described below by way of example.

[0094] Figure 4 This illustration shows a schematic diagram of a first optical communication system provided in an embodiment of this application. The optical communication system in... Figure 2The illustrated optical communication system is supplemented with a dual-fiber to single-fiber device 500 (specifically, multiple first dual-fiber to single-fiber devices 501 and multiple second dual-fiber to single-fiber devices 502). For example... Figure 4 As shown, the optical communication system includes a central optical module 200, a splitter / combiner 300, multiple remote optical modules 400, multiple first dual-fiber to single-fiber devices 501, and multiple second dual-fiber to single-fiber devices 502. The central optical module 200 is connected to the splitter / combiner 300 via optical fibers. The splitter / combiner 300 includes multiple transmitting ports (indicated by black boxes) and multiple receiving ports (indicated by white boxes). The multiple transmitting ports are respectively connected to the receiving optical fibers 4 of the multiple first dual-fiber to single-fiber devices 501, and the multiple receiving ports are respectively connected to the transmitting optical fibers 3 of the multiple first dual-fiber to single-fiber devices 501. The multiple first dual-fiber to single-fiber devices 501 are respectively connected to the multiple second dual-fiber to single-fiber devices 502 via bidirectional optical fibers 2. The transmitting optical fibers 3 of the multiple second dual-fiber to single-fiber devices 502 are respectively connected to the receiving ports of the multiple remote optical modules 400, and the receiving optical fibers 4 of the multiple second dual-fiber to single-fiber devices 502 are respectively connected to the transmitting ports of the multiple remote optical modules 400.

[0095] Figure 5 It shows Figure 4 A schematic diagram of the internal structure of the first dual-fiber to single-fiber device 501 and the second dual-fiber to single-fiber device 502. Furthermore, by way of example, Figure 5 The first dual-fiber to single-fiber device 501 and the second dual-fiber to single-fiber device 502 are Figure 4 The leftmost two-fiber to single-fiber devices are 501 and 502. (Example) Figure 5 As shown, the first dual-fiber to single-fiber device 501 and the second dual-fiber to single-fiber device 502 include a device body 1, from which bidirectional optical fibers 2, transmitting optical fibers 3, and receiving optical fibers 4 extend. A filter 12 is provided inside the device body 1. The filter 12 is used to transmit the light beam received through the bidirectional optical fiber 2 to the transmitting optical fiber 3, and to transmit the light beam received through the receiving optical fiber 4 back to the bidirectional optical fiber 2. The specific implementation will be described in detail later.

[0096] Reference Figure 4 and Figure 5As shown by the solid arrows, in the downlink direction, the central optical module 200 sends a first downlink beam (beam λ1'2'3') to the optical splitter / combiner 300. The splitter in the optical splitter / combiner 300 receives the first downlink beam and sends it to the demultiplexer. The demultiplexer splits the first downlink beam into multiple second downlink beams (beam λ1', beam λ2', and beam λ3'), and sends these multiple second downlink beams through multiple transmitting ports. Multiple first dual-fiber to single-fiber devices 501 receive the second downlink beams through receiving fiber 4 and transmit them through bidirectional fiber 2. Multiple second dual-fiber to single-fiber devices 502 receive the second downlink beams through bidirectional fiber 2 and transmit them through transmitting fiber 3. Multiple remote optical modules 400 each receive their corresponding second downlink beam. Different remote optical modules 400 correspond to different downlink wavelengths.

[0097] Reference Figure 4 and Figure 5 As shown by the dashed arrows, in the uplink direction, multiple remote optical modules 400 respectively transmit first uplink beams (beams λ1, λ2, and λ3). Multiple second dual-fiber to single-fiber devices 502 respectively receive the first uplink beams through receiving fiber 4 and transmit the first uplink beams through bidirectional fiber 2. Multiple first dual-fiber to single-fiber devices 501 receive the first uplink beams and transmit the first uplink beams through transmitting fiber 3. A splitter / combiner 300 receives multiple first uplink beams through multiple receiving ports. A combiner combines the multiple first uplink beams into a second uplink beam (λ123) and transmits the second uplink beam to the central optical module 200.

[0098] from Figure 4 As can be seen, by setting the first dual-fiber to single-fiber device 501 and the second dual-fiber to single-fiber device 502, the two optical fibers between each remote optical module 400 and the optical splitting and combining device 300 are converted into a single optical fiber (i.e., bidirectional optical fiber 2), which not only reduces the number of optical fibers, but also eliminates the need to redevelop the single-fiber bidirectional optical module.

[0099] Figure 6 A schematic diagram of a second optical communication system provided in an embodiment of this application is shown. This optical communication system... Figure 3 The illustrated optical communication system incorporates a dual-fiber to single-fiber converter 500. For example... Figure 6As shown, the optical communication system includes a central optical module 200, a splitter / combiner 300, multiple remote optical modules 400, and multiple dual-fiber to single-fiber devices 500. The central optical module 200 is connected to the splitter / combiner 300. The splitter / combiner 300 includes multiple ports (bidirectional transmission ports), which are respectively connected to the bidirectional optical fibers 2 of the multiple dual-fiber to single-fiber devices 500 (they can be directly connected or connected through extension fibers 7). The transmitting optical fibers 3 of the multiple dual-fiber to single-fiber devices 500 are respectively connected to the receiving ports of the multiple remote optical modules 400, and the receiving optical fibers 4 of the multiple dual-fiber to single-fiber devices 500 are respectively connected to the transmitting ports of the multiple remote optical modules 400. The splitter / combiner 300 includes a splitter that uses a power splitting method to split the light.

[0100] Figure 7 It shows Figure 6 A schematic diagram of the internal structure of the dual-fiber to single-fiber device 500. Furthermore, by way of example, Figure 7 The dual-fiber to single-fiber device 500 is Figure 6 The leftmost one is the dual-fiber to single-fiber device 500.

[0101] Reference Figure 6 and Figure 7 As shown by the solid arrows, in the downlink direction, the central optical module 200 sends a first downlink beam (beam λ1'2'3') to the optical splitter / combiner 300. The optical splitter / combiner 300 splits the first downlink beam (beam λ1'2'3') into multiple second downlink beams (beam λ1'2'3'), and sends these multiple second downlink beams through multiple ports. Each dual-fiber to single-fiber device 500 receives the second downlink beam (beam λ1'2'3') through bidirectional optical fiber 2 and sends the second downlink beam (beam λ1'2'3') through transmitting optical fiber 3. Each remote optical module 400 filters out the beam (beam λ1', beam λ2', or beam λ3') of the corresponding downlink wavelength from the second downlink beam (beam λ1'2'3'). Since different remote optical modules 400 correspond to different downlink wavelengths, the filters included in different remote optical modules 400 are also different.

[0102] like Figure 6 As shown, since multiple ports of the optical splitter / combiner 300 transmit a second downlink beam of the same wavelength, and the transmitting fibers 3 of multiple dual-fiber to single-fiber devices 500 also transmit a second downlink beam of the same wavelength (all beams λ1'2'3'), therefore, Figure 6 The positions of multiple dual-fiber to single-fiber devices 500 and multiple remote optical modules 400 can be interchanged, which improves the flexibility of optical communication system networking.

[0103] Reference Figure 6 and Figure 7As shown by the dashed arrows, in the uplink direction, multiple remote optical modules 400 respectively transmit first uplink beams (beams λ1, λ2, and λ3), wherein different remote optical modules 400 correspond to different uplink wavelengths. Each dual-fiber to single-fiber device 500 receives the first uplink beam (beam λ1, λ2, or λ3) through receiving fiber 4 and transmits the first uplink beam through bidirectional fiber 2. The optical splitter / combiner 300 receives the first uplink beams transmitted by multiple dual-fiber to single-fiber devices 500 through multiple ports, combines the multiple first uplink beams (beams λ1, λ2, and λ3) into a second uplink beam (beam λ123), and transmits the second uplink beam to the central optical module 200.

[0104] from Figure 6 As can be seen, by adding a dual-fiber to single-fiber device 500, the two optical fibers between each remote optical module 400 and the optical splitter / combiner 300 are converted into a single optical fiber (i.e., bidirectional fiber 2). This not only reduces the number of optical fibers but also eliminates the need to develop a new single-fiber bidirectional optical module. Furthermore, the optical splitter / combiner 300 can be freed from... Figure 3 The optical coupler and beam splitter in the process.

[0105] Figure 8 A schematic diagram of a third optical communication system provided in an embodiment of this application is shown, such as... Figure 8 As shown, the optical communication system includes a central optical module 200, a splitter / combiner 300, multiple remote optical modules 400, and multiple dual-fiber to single-fiber devices 500. The central optical module 200 is connected to the splitter / combiner 300. The splitter / combiner 300 includes multiple ports (bidirectional transmission ports), which are respectively connected to the bidirectional optical fibers 2 of the multiple dual-fiber to single-fiber devices 500. The transmitting optical fibers 3 of the multiple dual-fiber to single-fiber devices 500 are respectively connected to the receiving ports of the multiple remote optical modules 400, and the receiving optical fibers 4 of the multiple dual-fiber to single-fiber devices 500 are respectively connected to the transmitting ports of the multiple remote optical modules 400. The splitter / combiner 300 includes a splitter that uses a power-division method to split the light. Figure 8 The remote optical module 400 in the middle does not have a filter for filtering out the corresponding wavelength of the beam from the received beam.

[0106] Figure 9 It shows Figure 8 A schematic diagram of the internal structure of the dual-fiber to single-fiber device 500 is shown, and, by way of example, Figure 9 The dual-fiber to single-fiber device 500 is Figure 8 The leftmost one is the dual-fiber to single-fiber device 500.

[0107] Reference Figure 8 and Figure 9As shown by the solid arrows, in the downlink direction, the central optical module 200 sends a first downlink beam (beam λ1'2'3') to the optical splitter / combiner 300. The optical splitter / combiner 300 splits the first downlink beam (beam λ1'2'3') into multiple second downlink beams (beam λ1'2'3'), and sends these multiple second downlink beams through multiple ports. Each dual-fiber to single-fiber device 500 receives the second downlink beam (beam λ1'2'3') through bidirectional optical fiber 2. The filter 12 of each dual-fiber to single-fiber device 500 filters out the beam of the corresponding downlink wavelength (such as beam λ1') from the second downlink beam (beam λ1'2'3'), and sends it to the corresponding remote optical module 400 through the transmitting optical fiber 3. Since different dual-fiber to single-fiber devices 500 correspond to different downlink wavelengths, the filter 12 in different dual-fiber to single-fiber devices 500 is also different. Since the filter 12 in the dual-fiber to single-fiber device 500 can filter out the beam of the corresponding downward wavelength from the second downward beam, the remote optical module 400 does not need to be equipped with a filter.

[0108] Furthermore, the dual-fiber to single-fiber device 500 and the remote optical module 400 are in one-to-one correspondence. For example, if the dual-fiber to single-fiber device 500 is used to filter out the downlink wavelength λ1', then this dual-fiber to single-fiber device 500 can only be connected to the remote optical module 400 corresponding to the downlink wavelength λ1'. Otherwise, the remote optical module 400 cannot process or recognize the wavelength λ1'. Thus, in Figure 8 If the positions of the multiple dual-fiber to single-fiber devices 500 remain unchanged, the positions of the multiple remote optical modules 400 cannot be interchanged. It should be further noted that, for example... Figure 8 As shown, since multiple ports of the optical splitter / combiner 300 output second downlink beams with the same wavelength (all beams λ1'2'3'), the remote optical module 400, along with the corresponding dual-fiber to single-fiber device 500, can be plugged into any port of the optical splitter / combiner 300. That is, the remote optical module 400, along with the corresponding dual-fiber to single-fiber device 500, can be plugged into any port of the optical splitter / combiner 300. Figure 8 The remote optical module 400, along with its corresponding dual-fiber to single-fiber device 500, forms a single component. Figure 8 The positions of the three components can be interchanged. This also improves the flexibility of optical communication system networking.

[0109] Reference Figure 8 and Figure 9As shown by the dashed arrows, in the uplink direction, multiple remote optical modules 400 respectively transmit first uplink beams (beams λ1, λ2, and λ3), wherein different remote optical modules 400 correspond to different uplink wavelengths. Each dual-fiber to single-fiber device 500 receives the first uplink beam (beam λ1, λ2, or λ3) through receiving fiber 4 and transmits the first uplink beam through bidirectional fiber 2. The optical splitter / combiner 300 receives the first uplink beams transmitted by multiple dual-fiber to single-fiber devices 500 through multiple ports, combines the multiple first uplink beams (beams λ1, λ2, and λ3) into a second uplink beam (beam λ123), and transmits the second uplink beam (beam λ123) to the central optical module 200.

[0110] from Figure 8 As can be seen, by setting up the dual-fiber to single-fiber device 500, the two optical fibers between each remote optical module 400 and the optical splitter / combiner 300 are converted into a single optical fiber. This not only reduces the number of optical fibers but also eliminates the need to develop a new single-fiber bidirectional optical module. Furthermore, the optical splitter / combiner 300 can eliminate the need for... Figure 3 The optical coupler and beam splitter in the process.

[0111] It should be noted that, in Figures 2-4 as well as Figure 6 and Figure 8 In the optical module 400 and the central optical module 200, a photodiode (PD) and a laser diode (LD) are included. The PD is used to receive optical signals, and the LD is used to transmit optical signals.

[0112] The implementation of the above-mentioned dual-fiber to single-fiber device 500 will be explained below.

[0113] In some examples, such as Figure 5 , Figure 7 , Figure 9 , Figure 11 and Figures 17-22 As shown, the dual-fiber to single-fiber device 500 includes a device body 1, a bidirectional optical fiber 2, a transmitting optical fiber 3, and a receiving optical fiber 4. A filter 12 is disposed inside the device body 1. One end of each of the bidirectional optical fiber 2, transmitting optical fiber 3, and receiving optical fiber 4 extends into the device body 1, while the other end is located outside the device body 1. The filter 12 is used to transmit the light beam received from the receiving optical fiber 4 to the bidirectional optical fiber 2. Therefore, the filter 12 is located on the outgoing optical path of the receiving optical fiber 4, and the bidirectional optical fiber 2 is located on the first outgoing optical path (one of a reflection path and a transmission path) of the filter 12. The filter 12 is also used to transmit the light beam received from the bidirectional optical fiber 2 to the transmitting optical fiber 3. Therefore, the filter 12 is located on the outgoing optical path of the bidirectional optical fiber 2, and the transmitting optical fiber 3 is located on the second outgoing optical path (one of a reflection path and a transmission path) of the filter 12.

[0114] In some examples, such as Figure 5 , Figure 7 , Figure 9 , Figure 17 , Figure 19 and Figure 21 As shown, in the transmission direction from the receiving fiber 4 to the bidirectional fiber 2, the filter 12 is located on the outgoing optical path of the receiving fiber 4, and the bidirectional fiber 2 is located on the reflected optical path of the filter 12. In the transmission direction from the bidirectional fiber 2 to the transmitting fiber 3, the filter 12 is located on the outgoing optical path of the bidirectional fiber 2, and the transmitting fiber 3 is located on the transmission optical path of the filter 12. That is, the filter 12 is used to reflect the light beam received from the receiving fiber 4 towards the bidirectional fiber 2; and to transmit the light beam received from the bidirectional fiber 2 towards the transmitting fiber 3.

[0115] In this context, "one component is located on the outgoing light path, reflected light path, or transmitted light path of another component" means that the light emitted, reflected, or transmitted by the other component can reach that component. This arrival can be direct or it can be achieved by being redirected by a lens.

[0116] In other examples, such as Figure 11 , Figure 18 , Figure 20 and Figure 22 As shown, in the transmission direction from the receiving fiber 4 to the bidirectional fiber 2, the filter 12 is located on the outgoing optical path of the receiving fiber 4, and the bidirectional fiber 2 is located on the transmission optical path of the filter 12. In the transmission direction from the bidirectional fiber 2 to the transmitting fiber 3, the filter 12 is located on the outgoing optical path of the bidirectional fiber 2, and the transmitting fiber 3 is located on the reflected optical path of the filter 12. That is, the filter 12 is used to transmit the light beam received from the receiving fiber 4 into the bidirectional fiber 2; and to reflect the light beam received from the bidirectional fiber 2 into the transmitting fiber 3.

[0117] It should be noted that, in Figure 11 , Figures 17-22 In the accompanying drawings, Scheme 1 illustrates the application of the illustrated dual-fiber to single-fiber device 500. Figure 4 In the first optical communication system shown, specifically the leftmost second dual-fiber to single-fiber device 502, the values ​​of λa, λb, and λc are given. Scheme two shows the values ​​of λa, λb, and λc when the illustrated dual-fiber to single-fiber device 500 is applied... Figure 6 In the second optical communication system shown, specifically the leftmost dual-fiber to single-fiber device 500, the values ​​of λa, λb, and λc are given. Scheme three illustrates the application of the illustrated dual-fiber to single-fiber device 500 in... Figure 8 The values ​​of λa, λb, and λc are shown in the third type of optical communication system, specifically when it is the leftmost dual-fiber to single-fiber device 500.

[0118] It should also be noted that the prerequisite for the filter 12 to transmit the light beam received from the receiving fiber 4 to the bidirectional fiber 2 and the light beam received from the bidirectional fiber 2 to the transmitting fiber 3 is that the wavelengths of the light beam received by the receiving fiber 4 and the light beam received by the bidirectional fiber 2 meet certain requirements.

[0119] Specifically, the filter 12 is configured to reflect the light beam (uplink beam) received from the receiving fiber 4 into the bidirectional fiber 2, and to transmit the light beam (downlink beam) received from the bidirectional fiber 2 into the transmitting fiber 3. For the filter 12 to transmit the light beam according to the above transmission method, at least one wavelength of the uplink beam must belong to the reflection band of the filter 12, and at least one wavelength of the downlink beam must belong to the transmission band of the filter 12. Otherwise, the light beam will not be transmitted according to the designed transmission method.

[0120] Accordingly, the filter 12 is configured to transmit the light beam (uplink beam) received from the receiving fiber 4 into the bidirectional fiber 2, and to reflect the light beam (downlink beam) received from the bidirectional fiber 2 into the transmitting fiber 3. In order for the filter 12 to transmit the light beam according to the above transmission method, at least one wavelength of the uplink beam must belong to the transmission band of the filter 12, and at least one wavelength of the downlink beam must belong to the reflection band of the filter 12.

[0121] The transmission and reflection bands of the filter 12 in the dual-fiber to single-fiber device 500 used in the above three optical communication systems will be described below.

[0122] (1) For the dual-fiber to single-fiber device 500 applied in the first type of optical communication system. Assume that the optical communication system uses N wavelength division multiplexer (WDM) wavelengths, of which N / 2 WDM wavelengths are used for downlink beam transmission and the other N / 2 WDM wavelengths are used for uplink beam transmission. The WDM wavelengths referred to in the embodiments of this application can be coarse wavelength division multiplexer (CWDM) wavelengths, medium wavelength division multiplexer (MWDM) wavelengths, or light wavelength division multiplexer (LWDM) wavelengths.

[0123] In some examples, for the implementation of filter 12 for transmitting a second downlink beam received from bidirectional fiber 2 to transmitting fiber 3, the transmission band of filter 12 covers N / 2 WDM wavelengths for downlink. The reflection band of filter 12 covers N / 2 WDM wavelengths for uplink.

[0124] For the implementation of filter 12 for reflecting the second downlink beam received from bidirectional optical fiber 2 to transmitting optical fiber 3, the reflection band of filter 12 covers N / 2 WDM wavelengths used for downlink. The transmission band of filter 12 covers N / 2 WDM wavelengths used for uplink.

[0125] In some examples, the N / 2 WDM wavelengths used for downlink are the shorter half of the N WDM wavelengths, and the N / 2 WDM wavelengths used for uplink are the longer half of the N WDM wavelengths. In this case, the boundary wavelength between the transmission and reflection bands of filter 12 can be set between the longest WDM wavelength used for downlink and the shortest WDM wavelength used for uplink.

[0126] In other examples, the N / 2 WDM wavelengths used for downlink are the longer half of the N WDM wavelengths, and the N / 2 WDM wavelengths used for uplink are the shorter half of the N WDM wavelengths. In this case, the boundary wavelength between the transmission and reflection bands of filter 12 can be set between the shortest WDM wavelength used for downlink and the longest WDM wavelength used for uplink.

[0127] (2) For the dual-fiber to single-fiber device 500 used in the second type of optical communication system. For example... Figure 6 As shown, the dual-fiber to single-fiber device 500 receives a second downlink beam (beam λ1'2'3') containing multiple WDM wavelengths through the bidirectional optical fiber 2, and needs to send this second downlink beam containing multiple WDM wavelengths to the remote optical module 400.

[0128] Assuming the optical communication system uses N WDM wavelengths, where N / 2 WDM wavelengths are used for downlink beam transmission and the other N / 2 WDM wavelengths are used for uplink beam transmission, then for the implementation of filter 12 for transmitting the second downlink beam received from bidirectional fiber 2 to transmitting fiber 3, the transmission band of filter 12 covers the N / 2 WDM wavelengths used for downlink transmission. Additionally, the reflection band of filter 12 covers the N / 2 WDM wavelengths used for uplink transmission.

[0129] For the implementation of filter 12 to reflect the second downlink beam received from bidirectional optical fiber 2 to transmitting optical fiber 3, the reflection band of filter 12 is required to cover N / 2 WDM wavelengths used for downlink. The transmission band of filter 12 is required to cover N / 2 WDM wavelengths used for uplink.

[0130] In some examples, the N / 2 WDM wavelengths used for downlink are the shorter half of the N WDM wavelengths, and the N / 2 WDM wavelengths used for uplink are the longer half of the N WDM wavelengths. In this case, the boundary wavelength between the transmission and reflection bands of filter 12 can be set between the longest WDM wavelength used for downlink and the shortest WDM wavelength used for uplink.

[0131] In other examples, the N / 2 WDM wavelengths used for downlink are the longer half of the N WDM wavelengths, and the N / 2 WDM wavelengths used for uplink are the shorter half of the N WDM wavelengths. In this case, the boundary wavelength between the transmission and reflection bands of filter 12 can be set between the shortest WDM wavelength used for downlink and the longest WDM wavelength used for uplink.

[0132] (3) For the dual-fiber to single-fiber device 500 used in the third type of optical communication system. For example... Figure 8 As shown, the dual-fiber to single-fiber device 500 receives a second downlink beam (beam λ1'2'3') containing multiple WDM wavelengths through the bidirectional optical fiber 2, and needs to transmit a beam containing one WDM wavelength (such as beam λ1') to the remote optical module 400. That is, the filter 12 needs to filter the received second downlink beam.

[0133] Assuming the optical communication system uses N WDM wavelengths, where N / 2 WDM wavelengths are used for downlink beam transmission and the other N / 2 WDM wavelengths are used for uplink beam transmission, then for the implementation of filter 12 for transmitting the second downlink beam received from bidirectional fiber 2 to transmitting fiber 3, the transmission band of filter 12 only covers one WDM wavelength, which is used for downlink beam transmission. For example, it is required that the transmission band of filter 12 only covers one CWDM wavelength, MWDM wavelength, or LWDM wavelength. Furthermore, the transmission bands of filters 12 included in different dual-fiber to single-fiber devices 500 in the optical communication system are different. For example, if there are N / 2 dual-fiber to single-fiber devices 500, the transmission bands of these N / 2 dual-fiber to single-fiber devices 500 respectively cover N / 2 different WDM wavelengths used for downlink transmission.

[0134] For the implementation of filter 12 for reflecting the second downlink beam received from bidirectional optical fiber 2 to transmitting optical fiber 3, the reflection band of filter 12 covers only one WDM wavelength, which is used for downlink beam transmission. For example, it is required that the reflection band of filter 12 covers only one CWDM wavelength, MWDM wavelength, or LWDM wavelength. Furthermore, the reflection bands of filters 12 included in different dual-fiber to single-fiber devices 500 in the optical communication system are different. For example, if there are N / 2 dual-fiber to single-fiber devices 500, the reflection bands of the N / 2 dual-fiber to single-fiber devices 500 respectively cover N / 2 different WDM wavelengths used for downlink transmission.

[0135] The implementation of the device body 1 will be described below by way of example.

[0136] In some examples, such as Figure 7 , Figure 9 , Figure 11 , Figures 17-22 As shown, the device body 1 includes a housing 11 and a filter 12, with the filter 12 located inside the housing 11. For example, the housing 11 is elongated and has two ends that are positioned opposite each other along its length.

[0137] In some examples, such as Figure 7 , Figure 9 , Figure 11 , Figures 17-20 As shown, the device body 1 also includes a first collimating lens 13 and a second collimating lens 14, which are arranged on both sides of the filter 12. For example, the filter 12 can be attached to either the first collimating lens 13 or the second collimating lens 14.

[0138] In some examples, such as Figure 21 and Figure 22 As shown, the main body 1 of the device also includes a prism 10, and a filter 12 is attached to the prism 10.

[0139] Because filter 12 splits and combines light through transmission and reflection. Therefore, generally speaking, as... Figure 10 and Figure 12 As shown, the transmitting optical fiber 3 and the receiving optical fiber 4 extend from both ends of the device body 1, respectively. The bidirectional optical fiber 2 extends from the same end of the device body 1 as the transmitting optical fiber 3, or from the same end of the device body 1 as the receiving optical fiber 4.

[0140] In some examples, such as Figure 10 and Figure 9As shown, the filter 12 is used to reflect the light beam received from the receiving fiber 4 towards the bidirectional fiber 2; and to transmit the light beam received from the bidirectional fiber 2 towards the transmitting fiber 3. The bidirectional fiber 2 and the receiving fiber 4 extend from the same end of the device body 1.

[0141] In other examples, such as Figure 12 and Figure 11 As shown, the filter 12 is used to transmit the light beam received from the receiving fiber 4 into the bidirectional fiber 2; and to reflect the light beam received from the bidirectional fiber 2 into the transmitting fiber 3. The bidirectional fiber 2 and the transmitting fiber 3 extend from the same end of the device body 1.

[0142] like Figure 10 and Figure 12 As shown, since the transmitting fiber 3 and the receiving fiber 4 extend from both ends of the device body 1, and both fibers need to be connected to the transmitting and receiving ports of the same optical module, one of the transmitting fiber 3 and the receiving fiber 4 needs to be bent. For example, for Figure 10 In the dual-fiber to single-fiber device 500, the receiving fiber 4 needs to be bent. For Figure 12 In the dual-fiber to single-fiber device 500, the transmitting fiber 3 needs to be bent.

[0143] To avoid excessively small bending radii in optical fibers, in some examples, such as... Figures 13-15 As shown, the dual-fiber to single-fiber device 500 also includes a housing 5, which includes two opposing first sidewalls 511. The device body 1 is located inside the housing 5, and at least one fiber coil 514 is provided inside the housing 5. The transmitting fiber 3 or the receiving fiber 4 is coiled in at least one fiber coil 514, and the transmitting fiber 3 and the receiving fiber 4 extend from the same first sidewall 511 of the two first sidewalls 511. Since the transmitting fiber 3 and the receiving fiber 4 extend from the same first sidewall 511, it is convenient for the transmitting fiber 3 and the receiving fiber 4 to be connected to the receiving port and the transmitting port of the same optical module. Furthermore, the fiber coil 514 can support the bending of the transmitting fiber 3 or the receiving fiber 4, preventing the bending radius of the transmitting fiber 3 or the receiving fiber 4 from being too small.

[0144] In some examples, such as Figures 13-15 As shown, the bidirectional optical fiber 2 or the extended optical fiber 7 connected to the bidirectional optical fiber 2 extends from the other of the two first sidewalls 511.

[0145] It should be noted that, Figure 15 And the following Figure 26 and Figure 28 In this context, different thicknesses of optical fibers are used only to distinguish multiple optical fibers and do not represent the actual thickness of the optical fibers.

[0146] Besides the technical solution of setting up a housing 5 capable of coiling fibers to avoid excessively small bending radii for the optical fibers, in other examples, such as Figure 16 As shown, the transmitting fiber 3 and the receiving fiber 4 extend from the same end of the device body 1. This allows the transmitting fiber 3 and the receiving fiber 4 to be easily connected to the receiving and transmitting ports of the same optical module without bending.

[0147] To facilitate the transmission fiber 3 and the reception fiber 4 extending from the same end of the device body 1, in some examples, such as Figure 17 , Figure 19 or Figure 21 As shown, the device body 1 also contains at least one steering mirror 15, which is used to redirect the light beam transmitted by the receiving optical fiber 4 towards the filter 12. In other examples, such as Figure 18 , Figure 20 and Figure 22 As shown, the steering lens 15 is used to redirect the light beam reflected by the filter 12 to the rearward transmission fiber 3. The implementation of the steering lens 15 will be described below by way of example.

[0148] In some examples, such as Figure 17 and Figure 18 As shown, the light beam incident on filter 12 is perpendicular to filter 12. Therefore, the number of deflecting mirrors 15 is at least two. In some examples, such as... Figure 17 As shown, at least two steering mirrors 15 are used to deflect the beam transmitted by the receiving fiber 4 by 180° before sending it toward the filter 12. In other examples, such as Figure 18 As shown, at least two steering mirrors 15 are used to deflect the beam reflected by the filter 12 by 180° before sending it to the transmitting fiber 3. For example, there are two steering mirrors 15, each used to deflect the beam by 90°.

[0149] In some examples, such as Figures 19-22 As shown, the incident light beam onto filter 12 is not perpendicular to filter 12 (for example, the angle is 45°). Figure 19 and Figure 21 As shown, the deflecting lens 15 and the filter 12 are used to deflect the light beam transmitted by the receiving fiber 4 and exit from the filter 12, and the light beam transmitted by the receiving fiber 4 and the light beam exiting from the filter 12 are parallel and propagate in the same direction. In other examples, such as Figure 20 and Figure 22 As shown, the filter 12 and the deflecting lens 15 are used to deflect the light beam transmitted by the bidirectional optical fiber 2 and exit from at least one deflecting lens 15, wherein the light beam transmitted by the bidirectional optical fiber 2 and the light beam exiting from the deflecting lens 15 are parallel and have the same propagation direction. For example, there is one deflecting lens 15.

[0150] In some examples, such as Figure 17 and Figure 18 As shown, the device body 1 also has a third collimating lens 16 inside, which is located between the steering lens 15 and the transmitting optical fiber 3 or the receiving optical fiber 4.

[0151] In some examples, such as Figure 21 and Figure 22 As shown, the prism 10 is also provided with a first transmission film 17 and a second transmission film 18. In some examples, such as Figure 21 As shown, the first transmission film 17 is located between the bidirectional optical fiber 2 and the filter 12, and the second transmission film 18 is located between the receiving optical fiber 4 and the steering mirror 15. In other examples, such as Figure 22 As shown, the first transmission film 17 is located between the bidirectional optical fiber 2 and the filter 12, and the second transmission film 18 is located between the transmitting optical fiber 3 and the steering mirror 15. The first transmission film 17 and the second transmission film 18 are used to enhance the transmittance of the light beam in the prism 10 and reduce reflection loss.

[0152] In some examples, such as Figure 10 , Figures 12-16 As shown, the transmitting optical fiber 3 has a first optical fiber connector 31 at one end located outside the device body 1. The first optical fiber connector 31 is used to connect to the receiving port of the optical module. The receiving optical fiber 4 has a second optical fiber connector 41 at one end located outside the device body 1. The second optical fiber connector 41 is used to connect to the transmitting port of the optical module. This facilitates the connection of the dual-fiber to single-fiber device 500 to the optical module.

[0153] In some examples, the first fiber optic connector 31 and the second fiber optic connector 41 are fixed together side by side.

[0154] Because the dual-fiber to single-fiber device 500 is positioned near the remote optical module 400, it is relatively far from the optical splitter / combiner 300. Furthermore, the bidirectional fiber 2 inherent in the dual-fiber to single-fiber device 500 has a limited length, making it difficult to directly connect it to the optical splitter / combiner 300 or the first dual-fiber to single-fiber device 501 located near the optical splitter / combiner 300. Therefore, an extension fiber 7 needs to be connected to the bidirectional fiber 2, and the extension fiber 7 is used to connect to the optical splitter / combiner 300 or other dual-fiber to single-fiber devices 500.

[0155] This application does not limit the connection method between the bidirectional optical fiber 2 and the extension optical fiber 7. In some examples, the end of the bidirectional optical fiber 2 located outside the device body 1 is used to connect the extension optical fiber 7 by thermal fusion splicing. To facilitate the protection of the thermal fusion splice portion, in some examples, such as... Figure 23 , Figure 14 and Figure 15As shown, the dual-fiber to single-fiber device 500 also includes a housing 5, and the housing 5 has a heat-shrinkable tubing limiting structure 515 inside. The heat-shrinkable tubing limiting structure 515 is used to fix the heat-shrinkable tubing 6, which is used to loop around the heat-fusion splice portion of the bidirectional optical fiber 2 and the extension optical fiber 7. The housing 5 can also be called a fiber coil box or a splice box.

[0156] In some examples, such as Figure 23 and Figure 24 As shown, the heat shrink tubing limiting structure 515 includes two first plates 5151, which are fixed to the bottom wall 510 of the housing 5 and disposed opposite to each other. A first limiting groove 5150 is formed between the two first plates 5151, which is used to accommodate the heat shrink tubing 6. Exemplarily, the heat shrink tubing 6 is clamped between the two first plates 5151.

[0157] In some examples, such as Figure 24 As shown, the first plate 5151 includes a first intermediate section 5152 and two first side sections 5153 located on both sides of the first intermediate section 5152. The first intermediate section 5152 is connected to the bottom wall 510 of the box body 5. The bottom wall 510 has a first opening 5101 corresponding to the two first side sections 5153, so that the two first side sections 5153 are suspended. In this way, the two first side sections 5153 are more likely to undergo elastic deformation, so that the two first plates 5151 can better clamp the heat shrink tubing 6.

[0158] In some examples, such as Figure 23 As shown, the inside of the box 5 is also provided with a device body limiting structure 513, which is used to fix the device body 1.

[0159] In some examples, such as Figure 23 and Figure 25 As shown, the device body limiting structure 513 includes two second plates 5131, which are fixed to the bottom wall 510 of the housing 5 and arranged opposite to each other. A second limiting groove 5130 is formed between the two second plates 5131, which is used to accommodate the device body 1. For example, the device body 1 is clamped between the two second plates 5131.

[0160] In some examples, such as Figure 25 As shown, the second plate 5131 includes a second intermediate section 5132 and two second side sections 5133 located on both sides of the second intermediate section 5132. The second intermediate section 5132 is connected to the bottom wall 510 of the box body 5. The bottom wall 510 has a second opening 5102 corresponding to the two second side sections 5133, so that the two second side sections 5133 are suspended. In this way, the two second side sections 5133 are more likely to undergo elastic deformation, and can better clamp the heat shrink tubing 6.

[0161] In some examples, such as Figure 15 and Figure 26 As shown, the housing 5 includes two first sidewalls 511 arranged opposite to each other. The two first sidewalls 511 are respectively arranged opposite to the two ends of the device body 1 and opposite to the two ends of the heat shrink tubing 6. The transmitting optical fiber 3 and the receiving optical fiber 4 extend from one of the two first sidewalls 511, and the extension optical fiber 7 extends from the other of the two first sidewalls 511.

[0162] In some examples, such as Figure 23 As shown, multiple fiber optic coils 514 are provided between the device body limiting structure 513 and the heat shrink tubing limiting structure 515, and the multiple fiber optic coils 514 are arranged along the arrangement direction of the two first sidewalls 511. Two of the multiple fiber optic coils 514 located at both ends are closer to the first sidewalls 511 relative to the device body limiting structure 513 and the heat shrink tubing limiting structure 515. This facilitates fiber routing inside the housing 5.

[0163] In some examples, such as Figure 23 As shown, there are three fiber coils 514. The outer diameter of the middle fiber coil 514 is smaller than the outer diameter of the two fiber coils 514 located at both ends.

[0164] In some examples, such as Figure 23 As shown, the fiber spool 514 includes a spool body 5141 and a plurality of first fiber guides 5142. One end of the spool body 5141 is connected to the bottom wall 510, and the other end is connected to the plurality of first fiber guides 5142. The plurality of first fiber guides 5142 are arranged at intervals around the circumference of the spool body 5141.

[0165] In some examples, such as Figure 23 As shown, the housing 5 includes a bottom shell 51 and a top cover 52. The bottom shell 51 includes a bottom wall 510, two first side walls 511, and two second side walls 512. The two first side walls 511 are provided with fiber optic holes 5111 for optical fibers to pass through. A fiber optic snap-fit ​​structure 516 is provided on the bottom wall 510 corresponding to the two fiber optic holes 5111 for snapping optical fibers. One of the two second side walls 512 is connected to the top cover 52, and the other second side wall 512 is provided with a snap-fit ​​strip 5121, which has snap-fit ​​holes 5120. The top cover 52 is provided with a snap-fit ​​protrusion 521. When the top cover 52 is closed on the bottom shell 51, the snap-fit ​​protrusion 521 snaps into the snap-fit ​​hole 5120. The snap-fit ​​strip 5121 has openings on both sides to provide good elasticity.

[0166] In some examples, such as Figure 23As shown, a second baffle 517 is provided on the bottom shell 51. One end of the second baffle 517 is connected to the first side wall 511 or the second side wall 512, and the other end extends inward.

[0167] Besides the technical solution of connecting bidirectional fiber 2 and extension fiber 7 by thermal fusion splicing, in other examples, such as Figures 27-30 As shown, a third fiber optic connector 21 is provided at one end of the bidirectional optical fiber 2 located outside the device body 1. The third fiber optic connector 21 can be connected to the extension optical fiber 7 via an adapter. For example, both ends of the extension optical fiber 7 are provided with fiber optic connectors. One fiber optic connector is connected to the third fiber optic connector 21 of the bidirectional optical fiber 2 via an adapter, and the other fiber optic connector is used to connect to the port of the optical splitter / combiner 300 or other dual-fiber to single-fiber devices 500.

[0168] Figure 27 The transmitting fiber 3 and receiving fiber 4 of the illustrated dual-fiber to single-fiber device 500 extend from different ends of the device body 1. This necessitates bending either the transmitting fiber 3 or the receiving fiber 4 to mate with the receiving and transmitting ports of the same optical module. Therefore, as... Figure 28 and Figure 29 As shown, the dual-fiber to single-fiber device 500 also includes a housing 5. The transmitting fiber 3 or receiving fiber 4 is coiled inside the housing 5 using a fiber coil 514, and both the transmitting fiber 3 and receiving fiber 4 extend from the same first sidewall 511 of the housing 5. This facilitates the connection of the transmitting fiber 3 and receiving fiber 4 to the receiving and transmitting ports of the same optical module. Furthermore, since a third fiber optic connector 21 is provided at one end of the bidirectional fiber 2 located outside the device body 1, as... Figure 28 As shown, there is no need to install a heat shrink tubing limiting structure 515 inside the housing 5. The bidirectional optical fiber 2 extends directly from the other first side wall 511 of the housing 5, or, after being coiled in the fiber coil 514 inside the housing 5, it extends from the other first side wall 511.

[0169] Figure 30 The transmitting fiber 3 and receiving fiber 4 of the illustrated dual-fiber to single-fiber device 500 extend from the same end of the device body 1, allowing for easy connection to the receiving and transmitting ports of the same optical module. Therefore, Figure 30 The dual-fiber to single-fiber device 500 shown may not include the housing 5.

[0170] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A dual-fiber to single-fiber device, characterized in that, The dual-fiber to single-fiber device includes a device body (1), a bidirectional optical fiber (2), a transmitting optical fiber (3), and a receiving optical fiber (4). The device body (1) is provided with a filter (12) inside. One end of the bidirectional optical fiber (2), the transmitting optical fiber (3) and the receiving optical fiber (4) extends into the interior of the device body (1), and the other end is located outside the device body (1). The filter (12) is used to send the light beam received from the receiving optical fiber (4) to the bidirectional optical fiber (2). The filter (12) is located on the outgoing optical path of the receiving optical fiber (4), and the bidirectional optical fiber (2) is located on the first outgoing optical path of the filter (12). The first outgoing optical path is one of a reflected optical path and a transmitted optical path. The filter (12) is also used to transmit the light beam received from the bidirectional optical fiber (2) to the transmitting optical fiber (3). The filter (12) is located on the outgoing optical path of the bidirectional optical fiber (2), and the transmitting optical fiber (3) is located on the second outgoing optical path of the filter (12). The second outgoing optical path is either a reflected optical path or a transmitted optical path.

2. The dual-fiber to single-fiber device according to claim 1, characterized in that, The device body (1) includes two oppositely arranged ends, and the transmitting optical fiber (3) and the receiving optical fiber (4) extend from the two ends of the device body (1) respectively; The first outgoing optical path is a reflected optical path, the second outgoing optical path is a transmitted optical path, and the bidirectional optical fiber (2) and the receiving optical fiber (4) extend from the same end of the device body (1); or, the first outgoing optical path is a transmitted optical path, the second outgoing optical path is a reflected optical path, and the bidirectional optical fiber (2) and the transmitting optical fiber (3) extend from the same end of the device body (1).

3. The dual-fiber to single-fiber device according to claim 2, characterized in that, The dual-fiber to single-fiber device also includes a housing (5), the main body (1) of the device is located inside the housing (5), and at least one fiber coil (514) is provided inside the housing (5). The transmitting fiber (3) or the receiving fiber (4) is coiled in the at least one fiber coil (514), and the transmitting fiber (3) and the receiving fiber (4) extend from the same side wall of the housing (5).

4. The dual-fiber to single-fiber device according to claim 1, characterized in that, The device body (1) includes two opposite ends, the transmitting optical fiber (3) and the receiving optical fiber (4) extend from the same end of the device body (1), and the bidirectional optical fiber (2) extends from the other end of the device body (1).

5. The dual-fiber to single-fiber device according to claim 4, characterized in that, The device body (1) is also provided with at least one steering mirror (15). The first outgoing optical path is a reflected optical path, the second outgoing optical path is a transmitted optical path, and the at least one steering mirror (15) is located on the optical path between the receiving optical fiber (4) and the filter (12), used to deflect the light beam sent by the receiving optical fiber (4) and send it to the filter (12); or, The first outgoing optical path is a transmission optical path, the second outgoing optical path is a reflection optical path, and the at least one steering lens (15) is located on the optical path between the filter (12) and the transmitting optical fiber (3) to deflect the light beam reflected by the filter (12) and send it to the transmitting optical fiber (3).

6. The dual-fiber to single-fiber device according to claim 5, characterized in that, The incident light beam is perpendicular to the filter (12), and the number of the deflecting mirrors (15) is at least two. The at least two deflecting mirrors (15) are used to deflect the light beam sent by the receiving optical fiber (4) by 180° and send it to the filter (12), or to deflect the light beam reflected by the filter (12) by 180° and send it to the transmitting optical fiber (3).

7. The dual-fiber to single-fiber device according to claim 5, characterized in that, The light beam incident on the filter (12) is not perpendicular to the filter (12); The first outgoing optical path is a reflected optical path, and the second outgoing optical path is a transmitted optical path. The at least one steering mirror (15) and the filter (12) are used to deflect the light beam sent by the receiving optical fiber (4) and exit from the filter (12), and the light beam sent by the receiving optical fiber (4) and the light beam exiting from the filter (12) are parallel and have the same propagation direction; or, The first outgoing optical path is a transmission optical path, the second outgoing optical path is a reflection optical path, the filter (12) and the at least one steering mirror (15) are used to deflect the light beam sent by the bidirectional optical fiber (2) and exit from the at least one steering mirror (15), wherein the light beam sent by the bidirectional optical fiber (2) and the light beam exited by the at least one steering mirror (15) are parallel and have the same propagation direction.

8. The dual-fiber to single-fiber device according to any one of claims 1-7, characterized in that, The transmitting optical fiber (3) is provided with a first optical fiber connector (31) at one end outside the device body (1), and the first optical fiber connector (31) is used to connect to the receiving port of the optical module. The receiving optical fiber (4) is provided with a second optical fiber connector (41) at one end outside the device body (1). The second optical fiber connector (41) is used to connect to the transmitting port of the optical module.

9. The dual-fiber to single-fiber device according to any one of claims 1, 2, or 4-7, characterized in that, The bidirectional optical fiber (2) is located at one end outside the device body (1) and is used to connect the extension optical fiber (7) by thermal fusion. The dual-fiber to single-fiber device also includes a housing (5), and the housing (5) is provided with a heat shrink tubing limiting structure (515) inside. The heat shrink tubing limiting structure (515) is used to fix the heat shrink tubing (6), and the heat shrink tubing (6) is used to surround the heat fusion splice part of the bidirectional optical fiber (2) and the extension optical fiber (7).

10. The dual-fiber to single-fiber device according to claim 9, characterized in that, The heat shrink tubing limiting structure (515) includes two first plates (5151), which are fixed to the bottom wall (510) of the box (5) and arranged opposite to each other. A first limiting groove (5150) is formed between the two first plates (5151), and the first limiting groove (5150) is used to accommodate the heat shrink tubing (6).

11. The dual-fiber to single-fiber device according to claim 10, characterized in that, The first plate (5151) includes a first intermediate section (5152) and two first side sections (5153) located on both sides of the first intermediate section (5152); The first intermediate section (5152) is connected to the bottom wall (510) of the box body (5). The bottom wall (510) is provided with a first opening (5101) corresponding to the two first side sections (5153) so that the two first side sections (5153) are suspended.

12. The dual-fiber to single-fiber device according to claim 9, characterized in that, The box (5) is also provided with a device body limiting structure (513) inside, which is used to fix the device body (1).

13. The dual-fiber to single-fiber device according to claim 12, characterized in that, The device body limiting structure (513) includes two second plates (5131), which are fixed to the bottom wall (510) of the box (5) and arranged opposite to each other; A second limiting groove (5130) is formed between the two second plates (5131), and the second limiting groove (5130) is used to accommodate the device body (1).

14. The dual-fiber to single-fiber device according to claim 13, characterized in that, The second plate (5131) includes a second intermediate section (5132) and two second side sections (5133) located on both sides of the second intermediate section (5132); The second middle section (5132) is connected to the bottom wall (510) of the box body (5). The bottom wall (510) is provided with a second opening (5102) corresponding to the two second side sections (5133) so that the two second side sections (5133) are suspended.

15. The dual-fiber to single-fiber device according to claim 12, characterized in that, The box body (5) is further provided with at least one fiber coil (514), and the bidirectional optical fiber (2) and / or the extension optical fiber (7) are coiled in the at least one fiber coil (514).

16. The dual-fiber to single-fiber device according to claim 15, characterized in that, The housing (5) includes two first sidewalls (511) arranged opposite to each other, the transmitting optical fiber (3) or the receiving optical fiber (4) is coiled in at least one fiber coil (514), and the transmitting optical fiber (3) and the receiving optical fiber (4) extend from the same first sidewall (511) of the two first sidewalls (511). The extended optical fiber (7) extends from the other of the two first sidewalls (511).

17. The dual-fiber to single-fiber device according to claim 16, characterized in that, The two first sidewalls (511) are respectively disposed opposite to the two ends of the device body (1) and respectively disposed opposite to the two ends of the heat shrink tubing (6).

18. The dual-fiber to single-fiber device according to claim 17, characterized in that, The number of the fiber optic coils (514) is multiple, and the multiple fiber optic coils (514) are arranged along the arrangement direction of the two first sidewalls (511) and located between the device body limiting structure (513) and the heat shrink tubing limiting structure (515). Along the arrangement direction of the two first sidewalls (511), two of the multiple fiber coils (514) located at both ends are close to the first sidewalls (511) relative to the device body limiting structure (513) and the heat shrink tubing limiting structure (515).

19. The dual-fiber to single-fiber device according to claim 18, characterized in that, The number of the fiber coils (514) is three. The outer diameter of the middle fiber coil (514) is smaller than the outer diameter of the two fiber coils (514) located at both ends.

20. The dual-fiber to single-fiber device according to any one of claims 1-7, characterized in that, The bidirectional optical fiber (2) has a third optical fiber connector (21) at one end located outside the device body (1).

21. The dual-fiber to single-fiber device according to any one of claims 1-7, characterized in that, The first outgoing optical path is a transmission optical path, the second outgoing optical path is a reflection optical path, and the reflection band of the filter (12) covers multiple wavelength division multiplexer (WDM) bands; or, The first outgoing optical path is a reflected optical path, the second outgoing optical path is a transmitted optical path, and the transmission band of the filter (12) covers multiple WDM bands.

22. The dual-fiber to single-fiber device according to any one of claims 1-7, characterized in that, The first outgoing optical path is a transmission optical path, the second outgoing optical path is a reflection optical path, and the reflection band of the filter (12) only covers one wavelength division multiplexer (WDM) wavelength; or, The first outgoing optical path is a reflected optical path, the second outgoing optical path is a transmitted optical path, and the transmission band of the filter (12) only covers one WDM wavelength.

23. An optical communication system, characterized in that, The optical communication system includes a central optical module (200), a splitting and combining optical device (300), multiple remote optical modules (400) and multiple dual-fiber to single-fiber devices (500), wherein the dual-fiber to single-fiber device (500) is a dual-fiber to single-fiber device as described in any one of claims 1-22; The central optical module (200) is connected to the optical splitter / combiner (300), which includes multiple ports, each of which is connected to the bidirectional optical fiber (2) of the multiple dual-fiber to single-fiber devices (500). The transmitting optical fibers (3) of the plurality of dual-fiber to single-fiber devices (500) are respectively connected to the receiving ports of the plurality of remote optical modules (400), and the receiving optical fibers (4) of the plurality of dual-fiber to single-fiber devices (500) are respectively connected to the transmitting ports of the plurality of remote optical modules (400).

24. The optical communication system according to claim 23, characterized in that, In the downlink direction, the central optical module (200) is used to send a first downlink beam to the optical splitter (300); the optical splitter (300) is used to split the first downlink beam into multiple second downlink beams and send the multiple second downlink beams through the multiple ports; each dual-fiber to single-fiber device (500) is used to receive the second downlink beam through the bidirectional optical fiber (2) and send the second downlink beam through the transmitting optical fiber (3); each remote optical module (400) is used to filter out the beam of the corresponding downlink wavelength from the second downlink beam, wherein different remote optical modules (400) correspond to different downlink wavelengths; In the uplink direction, each of the remote optical modules (400) is used to transmit a first uplink beam; each of the dual-fiber to single-fiber devices (500) is used to receive the first uplink beam through the receiving optical fiber (4) and transmit the first uplink beam through the bidirectional optical fiber (2); the optical splitter / combiner (300) is used to receive multiple first uplink beams through the multiple ports, combine the multiple first uplink beams into a second uplink beam, and transmit the second uplink beam to the central optical module (200).

25. The optical communication system according to claim 23, characterized in that, In the downlink direction, the central optical module (200) is used to send a first downlink beam to the optical splitter (300); the optical splitter (300) is used to split the first downlink beam into multiple second downlink beams and send the multiple second downlink beams through the multiple ports; each dual-fiber to single-fiber device (500) is used to receive the second downlink beam through the bidirectional optical fiber (2), and the filter (12) of each dual-fiber to single-fiber device (500) is used to filter out the beam of the corresponding downlink wavelength from the second downlink beam and send it to the corresponding remote optical module (400) through the transmitting optical fiber (3), wherein the downlink wavelengths corresponding to different dual-fiber to single-fiber devices (500) are different; In the uplink direction, each of the remote optical modules (400) is used to transmit a first uplink beam; each of the dual-fiber to single-fiber devices (500) is used to receive the first uplink beam through the receiving optical fiber (4) and transmit the first uplink beam through the bidirectional optical fiber (2); the optical splitter / combiner (300) is used to receive multiple first uplink beams through the multiple ports, combine the multiple first uplink beams into a second uplink beam, and transmit the second uplink beam to the central optical module (200).

26. An optical communication system, characterized in that, The optical communication system includes a central optical module (200), a splitting and combining optical device (300), multiple remote optical modules (400), multiple first dual-fiber to single-fiber devices (501) and multiple second dual-fiber to single-fiber devices (502), wherein the first dual-fiber to single-fiber devices (501) and the second dual-fiber to single-fiber devices (502) are both dual-fiber to single-fiber devices as described in any one of claims 1-22; The central optical module (200) is connected to the optical splitter / combiner (300). The optical splitter / combiner (300) includes multiple transmitting ports and multiple receiving ports. The multiple transmitting ports of the optical splitter / combiner (300) are respectively connected to the receiving optical fibers (4) of the multiple first dual-fiber to single-fiber devices (501), and the multiple receiving ports of the optical splitter / combiner (300) are respectively connected to the transmitting optical fibers (3) of the multiple first dual-fiber to single-fiber devices (501). The bidirectional optical fibers (2) of the plurality of first dual-fiber to single-fiber devices (501) are respectively connected to the bidirectional optical fibers (2) of the plurality of second dual-fiber to single-fiber devices (502), the transmitting optical fibers (3) of the plurality of second dual-fiber to single-fiber devices (502) are respectively connected to the receiving ports of the plurality of remote optical modules (400), and the receiving optical fibers (4) of the plurality of second dual-fiber to single-fiber devices (502) are respectively connected to the transmitting ports of the plurality of remote optical modules (400).

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