A fiber optic ring link suitable for bidirectional communication

Abstract

An optical fiber ring link suitable for bidirectional communication, belonging to the field of optical fiber communication, includes an optical signal transmitting component for outputting a first optical signal and a second optical signal; an optical signal receiving component for receiving the first and second optical signals; and a second coupler for receiving the first and second optical signals output by the optical signal transmitting component and transmitting them to a first loop and a second loop respectively, and also for receiving the first and second optical signals output by the first and second loops and transmitting them to the optical signal receiving component respectively. The first and second loops are connected in parallel through multiple circulators to form a ring link. In this ring link, the transmission directions of the first and second optical signals are split by multiple circulators, so that the first and second optical signals are transmitted in clockwise and counterclockwise directions along the ring link respectively. This application can solve the technical problem that existing optical fiber ring links are not suitable for bidirectional communication.

Description

Technical Field

[0001] This application relates to the field of optical fiber communication, and specifically to an optical fiber ring link suitable for bidirectional communication. Background Technology

[0002] In recent years, the data traffic of the entire Internet has grown exponentially, which has brought new challenges to the global fiber optic communication system.

[0003] Currently, commercially available fiber optic transmission systems are mainly constructed using traditional single-mode fiber, with a solid glass core (refractive index approximately 1.44). The internal optical signal transmission speed is approximately 2 × 10⁻⁶. 8 The transmission delay is greater than that of air, and due to the high temperature sensitivity of glass, its transmission delay varies greatly with temperature.

[0004] Hollow-core optical fiber has an air core (refractive index of approximately 1.003), and the internal optical signal transmission speed is approximately 3 × 10⁻⁶. 8 Compared to traditional single-mode fiber, the propagation speed can be increased by 46% and the delay can be reduced by 30%. Moreover, since the refractive index changes less with temperature, the temperature stability of the delay can be improved by about 20 times.

[0005] Meanwhile, because the backscattering of hollow fiber is about 30dB lower than that of traditional single-mode fiber, bidirectional transmission of the same wavelength through a single fiber becomes possible.

[0006] In addition, hollow fiber has very low nonlinearity and a damage threshold much higher than that of traditional solid fiber. It also has low dispersion and smaller differences between different wavelengths, as well as a wider wavelength range. Therefore, future transmission systems based on hollow fiber will have many advantages. They can use higher signal power, increase fiber transmission spans, reduce the number of optical amplification nodes in long-distance transmission, greatly simplify the structure of fiber optic links, and reduce network operation power consumption and construction costs.

[0007] Currently, both industry and academia have shown great interest in hollow-core optical fibers and have conducted extensive experimental research. In research on long-distance unidirectional transmission systems, due to the difficulty in constructing actual optical fiber transmission links of thousands or even tens of thousands of kilometers in the laboratory, optical fiber ring links are typically used. Relying on optical fiber ring links, researchers can construct optical fiber links with an equivalent transmission length far exceeding the actual fiber length using relatively short fiber links. The basic principle is to circulate a finite-time optical signal multiple times within a fixed-length optical fiber. For long-distance unidirectional transmission experimental systems using hollow-core optical fibers, the existing devices described above can be directly used to construct the corresponding hollow-core optical fiber ring links. However, current optical fiber ring links are not yet suitable for long-distance bidirectional transmission systems using hollow-core optical fibers. Summary of the Invention

[0008] This application provides an optical fiber ring link suitable for bidirectional communication, which can solve the technical problem that existing optical fiber ring links are not suitable for bidirectional communication.

[0009] In a first aspect, embodiments of this application provide an optical fiber ring link suitable for bidirectional communication, the optical fiber ring link comprising:

[0010] An optical signal transmitting component, which is used to output a first optical signal and a second optical signal;

[0011] An optical signal receiving component, used to receive a first optical signal and a second optical signal;

[0012] The second coupler is used to receive the first optical signal and the second optical signal output by the optical signal transmitting component and transmit them to the first circuit and the second circuit respectively. It is also used to receive the first optical signal and the second optical signal output by the first circuit and the second circuit and transmit them to the optical signal receiving component respectively.

[0013] The first circuit and the second circuit are connected in parallel through multiple circulators to form a ring link. In this ring link, the transmission directions of the first optical signal and the second optical signal are split by the multiple circulators so that the first optical signal and the second optical signal are transmitted in the clockwise and counterclockwise directions of the ring link, respectively.

[0014] In conjunction with the first aspect, in one embodiment, the optical signal transmitting component includes:

[0015] The optical signal transmitter is used to generate the raw optical signal;

[0016] The first optical switch is connected to the optical signal transmitter and is used to control the output of the original optical signal;

[0017] The first coupler, which is connected to the first optical switch, is used to split the original optical signal into a first optical signal and a second optical signal before outputting them.

[0018] In conjunction with the first aspect, in one embodiment, the fiber optic ring link further includes:

[0019] The first circulator is connected to the optical transmitting component, the optical receiving component and the second coupler. It is used to receive the first optical signal output by the optical transmitting component, adjust its direction and transmit it to the first loop through the second coupler. It is also used to receive the second optical signal output by the second loop through the second coupler, adjust its direction and transmit it to the optical receiving component.

[0020] The second circulator connects the optical transmitting component, the optical receiving component, and the second coupler. It is used to receive the second optical signal output by the optical transmitting component, adjust its direction, and transmit it to the second loop through the second coupler. It is also used to receive the first optical signal output by the first loop through the second coupler, adjust its direction, and transmit it to the optical receiving component.

[0021] In conjunction with the first aspect, in one embodiment, the fiber optic ring link further includes:

[0022] A 2-to-1 optical switch is connected to a first circulator, a second circulator, and an optical signal receiving component. It is used to select one of the first optical signal and the second optical signal output from the first circulator and the second circulator at the same time and send it to the optical signal receiving component.

[0023] In conjunction with the first aspect, in one embodiment, the ring link includes a third circulator, a fourth circulator, a fifth circulator, and a sixth circulator connected in sequence. A first branch of a first circuit and a second branch of a second circuit are connected in parallel between the third circulator and the fourth circulator. A first shared link segment of the first circuit and the second circuit is provided between the fourth circulator and the fifth circulator. A second branch of the first circuit and a first branch of the second circuit are connected in parallel between the fifth circulator and the sixth circulator. A second shared link segment of the first circuit and the second circuit is provided between the sixth circulator and the third circulator. The length of the first shared link is greater than the length of the second shared link.

[0024] The ring link also includes a second optical switch in the second branch of the first loop and a third optical switch in the second branch of the second loop.

[0025] In conjunction with the first aspect, in one embodiment, the ring link further includes a first signal amplifier disposed on the first loop and a second signal amplifier disposed on the second loop.

[0026] In conjunction with the first aspect, in one embodiment, the first signal amplifier includes a first amplifier disposed on a first branch of the first circuit and a third amplifier disposed on a second branch of the first circuit;

[0027] The second signal amplifier includes a fourth amplifier disposed on the first branch of the second circuit and a second amplifier disposed on the second branch of the second circuit.

[0028] In conjunction with the first aspect, in one embodiment, when the first optical signal and the second optical signal are wavelength division multiplexed optical signals, the ring link further includes a first equalizer disposed on the first loop and a second equalizer disposed on the second loop.

[0029] In conjunction with the first aspect, in one embodiment, the fiber optic ring link further includes:

[0030] A fiber optic loop control signal generator is used to generate a first control signal, a second control signal, a third control signal, and to acquire a trigger signal.

[0031] The first control signal is used to control the output of the optical signal transmitting component to the first optical signal and the second optical signal;

[0032] The second control signal is used to control the on / off state of the first circuit;

[0033] The third control signal is used to control the on / off state of the second circuit;

[0034] The acquisition trigger signal is used to control the optical signal receiving component to receive the first optical signal and the second optical signal.

[0035] In conjunction with the first aspect, in one embodiment, the duration of the optical signal output by the first control signal controlling the first optical signal and the second optical signal is calculated using the following formula:

[0036] T1 = L / (C / n)

[0037] in,

[0038] T1 represents the duration of the optical signal;

[0039] L represents the total length of the ring link;

[0040] C represents the speed of light in a vacuum;

[0041] n represents the refractive index of the optical fiber core. The beneficial effects of the technical solution provided in this application include:

[0042] By setting a second coupler to connect the input and output terminals of the first and second loops, the second coupler sends the first and second optical signals output by the optical signal transmitting component into the first and second loops respectively. By setting multiple circulators, the first and second loops are connected in parallel to form a ring link. In this ring link, the transmission directions of the first and second optical signals are split by multiple circulators, so that the first and second optical signals entering the ring link are transmitted in the clockwise and counterclockwise directions respectively, without interfering with each other. Finally, the second coupler sends the first and second optical signals output by the first and second loops to the optical receiving component, thereby obtaining a fiber optic ring link that realizes bidirectional communication. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the link structure of an embodiment of the fiber optic ring link applicable to bidirectional communication in this application;

[0044] Figure 2This is a timing diagram of control signals for an embodiment of a fiber optic ring link applicable to bidirectional communication according to this application. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0047] In a first aspect, embodiments of this application provide an optical fiber ring link suitable for bidirectional communication.

[0048] In one embodiment, reference is made to Figure 1 , Figure 1 This is a schematic diagram of a fiber optic ring link according to an embodiment of the present application for bidirectional communication. Figure 1 As shown, fiber optic ring links suitable for bidirectional communication include:

[0049] An optical signal transmitting component is used to output a first optical signal (Signal1) and a second optical signal (Signal2).

[0050] An optical signal receiving component, which is used to receive a first optical signal and a second optical signal.

[0051] The second coupler, that is Figure 1 Coupler 2 in the optical signal transmission component is used to receive the first optical signal and the second optical signal output by the optical signal transmission component and send them to the first circuit and the second circuit respectively. It is also used to receive the first optical signal and the second optical signal output by the first circuit and the second circuit and send them to the optical signal receiving component respectively.

[0052] The first circuit and the second circuit are connected in parallel through multiple circulators to form a ring link. In this ring link, the transmission directions of the first optical signal and the second optical signal are split by the multiple circulators so that the first optical signal and the second optical signal are transmitted in the clockwise and counterclockwise directions of the ring link, respectively.

[0053] In this embodiment, an optical signal transmitting component, a ring link, and an optical signal receiving component are connected by a second coupler. The second coupler sends the first and second optical signals output by the optical signal transmitting component into the ring link, respectively. The first and second optical signals are then transmitted along the first and second loops in the ring link, respectively. Finally, the second coupler receives the first and second optical signals emitted from the first and second loops and sends them to the optical signal receiving component, respectively. When the first and second optical signals are transmitted in the ring link, multiple circulators adjust their transmission mode so that they are transmitted in the first and second loops in the clockwise and counterclockwise directions of the ring link, respectively, without interfering with each other, thereby realizing bidirectional transmission of the first and second optical signals in the optical fiber ring link.

[0054] Specifically, taking the example of a first optical signal transmitted clockwise and a second optical signal transmitted counterclockwise in a ring link, a second coupler connects the input and output terminals of the first and second loops. The second coupler sends the first and second optical signals output from the optical signal transmitting component into the first and second loops, respectively. The first optical signal enters the first loop in a clockwise direction along the ring link, while the second optical signal enters the second loop in a counterclockwise direction. In other words, the second coupler can adjust the directions of the first and second optical signals when entering the ring link. Multiple circulators in the ring link split the transmission directions of the first and second optical signals, ensuring that the first optical signal always transmits clockwise and the second optical signal always transmits counterclockwise. Finally, the second coupler sends the first and second optical signals output from the first and second loops to the optical receiving component. Although the first and second optical signals are transmitted in the same ring link, they are transmitted along different loops in different directions, without interfering with each other, thus achieving a fiber optic ring link that enables bidirectional communication.

[0055] Furthermore, in one embodiment, the optical signal transmitting component includes:

[0056] The optical signal transmitter (TX) is used to generate the raw optical signal.

[0057] The first optical switch, that is Figure 1 The optical switch 1 in the middle is connected to the optical signal transmitter and is used to control the output of the original optical signal.

[0058] The first coupler, that is Figure 1 Coupler 1 in the middle is connected to the first optical switch and is used to split the original optical signal into a first optical signal and a second optical signal before outputting them.

[0059] In this embodiment, the optical signal transmitter is generally a wavelength division multiplexing (WDM) optical signal generator, but it can also be a single-wavelength optical signal generator. The signal type of the original optical signal, such as whether it is a WDM optical signal or a single-wavelength optical signal, can be adjusted by regulating the optical signal transmitter.

[0060] The raw optical signal generated at the optical signal transmitter first passes through a first optical switch. The on / off state of the first optical switch is precisely controlled by a fiber optic ring control signal generator, thereby outputting a raw optical signal of fixed duration. The duration of the raw optical signal can be adjusted by regulating the on / off duration of the first optical switch.

[0061] The original optical signal is split into two parts by a 1×2 50:50 first coupler: a first optical signal and a second optical signal. These two signals then pass through a second coupler and enter the first and second loops of the ring link, respectively. The proportions of the first and second optical signals in the original optical signal can be adjusted by regulating the splitting characteristics of the first coupler.

[0062] Furthermore, in one embodiment, the aforementioned fiber optic ring link further includes:

[0063] The first circulator, that is Figure 1 The circulator 1 in the middle is connected to the optical transmitting component, the optical receiving component and the second coupler. It is used to receive the first optical signal output by the optical transmitting component, adjust its direction and transmit it to the first loop through the second coupler. It is also used to receive the second optical signal output by the second loop through the second coupler, adjust its direction and send it to the optical receiving component.

[0064] The second circulator, that is Figure 1 The circulator 2 in the middle is connected to the optical transmitting component, the optical receiving component and the second coupler. It is used to receive the second optical signal output by the optical transmitting component, adjust its direction and transmit it to the second loop through the second coupler. It is also used to receive the first optical signal output by the first loop through the second coupler, adjust its direction and send it to the optical receiving component.

[0065] In this embodiment, taking the first optical signal transmitted clockwise in the ring link and the second optical signal transmitted counterclockwise in the ring link as an example, the first optical signal is adjusted in direction by the first circulator and then enters the first loop of the ring link in a clockwise direction through the second coupler. The second optical signal is adjusted in direction by the second circulator and then enters the second loop of the ring link in a counterclockwise direction through the second coupler. The first optical signal and the second optical signal enter a 2×2 50:50 second coupler from two directions. The second coupler connects the two ends of the optical fiber ring link. Therefore, the generated optical signals of fixed duration will enter the ring link for transmission from both clockwise and counterclockwise directions.

[0066] After the first and second optical signals circulate in the ring link at least once, they are both output through the second coupler. The output first optical signal enters the second circulator, where its direction is adjusted before transmission to the optical receiving component. The output second optical signal enters the first circulator, where its direction is adjusted before transmission to the optical receiving component. At this time, the first and second circulators may be processing the first and second optical signals entering the ring link simultaneously. Based on the fact that the first and second circulators have multiple ports, the direction of the incident and outgoing optical signals can be adjusted simultaneously within the same circulator using different ports. For example, the first optical signal can be input from port 1 and output from port 2 of the first circulator, and the second optical signal can be input from port 2 and output from port 3 of the first circulator. Therefore, at least the first and second circulators are sufficient to establish the transmission intermediary between the optical transmitting component and the ring link, as well as between the ring link and the optical receiving component. This transmission intermediary assists in achieving bidirectional communication of optical signals by splitting the optical transmission direction and can minimize the length of the fiber optic ring link.

[0067] Furthermore, in one embodiment, the aforementioned fiber optic ring link further includes:

[0068] 2-to-1 optical switch, that is Figure 1 The two-in-one selection device connects the first circulator, the second circulator, and the optical signal receiving component, and is used to select one of the first optical signal and the second optical signal output from the first circulator and the second circulator at the same time to send to the optical signal receiving component.

[0069] In this embodiment, the optical signal receiving component is connected to the first circulator and the second circulator via a 2-to-1 optical switch, which can select to allow the first optical signal or the second optical signal to pass through at a specific time, thereby adjusting the acquisition and subsequent processing of the first optical signal and the second optical signal.

[0070] Furthermore, in one embodiment, the aforementioned ring link includes a third circulator, a fourth circulator, a fifth circulator, and a sixth circulator connected in sequence, wherein the third circulator is also... Figure 1 The circulator 3, the fourth circulator, is... Figure 1 The circulator 4, the fifth circulator, is... Figure 1 Circulator 5, the sixth circulator, that is Figure 1 Circulator 6 in the middle.

[0071] The third circulator and the fourth circulator are connected in parallel with a first branch of the first circuit and a second branch of the second circuit. The fourth circulator and the fifth circulator are connected with a first shared link segment of the first circuit and the second circuit. The fifth circulator and the sixth circulator are connected in parallel with a second branch of the first circuit and a first branch of the second circuit. The sixth circulator and the third circulator are connected with a second shared link segment of the first circuit and the second circuit. The length of the first shared link is greater than the length of the second shared link.

[0072] The aforementioned ring link also includes a second optical switch located in the second branch of the first loop and a third optical switch located in the second branch of the second loop.

[0073] In this embodiment, the first optical signal and the second optical signal output by the optical transmitting component can be adjusted by adjusting the first optical switch. Repeatedly performing the opening and closing operation of the first optical switch can perform multiple rounds of optical signal output.

[0074] After the first optical signal is input into the first loop via the second coupler, it sequentially passes through the third circulator, the first branch of the first loop, the fourth circulator, the first shared link segment, the fifth circulator, the second branch of the first loop, the sixth circulator, and the second shared link segment. The first optical signal output from the second shared link segment reaches the optical signal receiving component via the second coupler. The second branch of the first loop is located at the end of the first loop, and the second optical switch is located on the second branch of the first loop, that is, the second optical switch is located at the end of the first loop. This has two advantages:

[0075] Firstly, looking in the clockwise direction, the link length from the second optical switch to the second coupler is only a small part of the first loop, and the link length between the second optical switch and the second circulator is also very short. If the first optical switch is turned on and the second optical switch is turned off at the same time, the amount of the first optical signal from the previous round on the transmission path between the second optical switch and the second circulator is relatively small, and the interference of the first optical signal from the previous round on the second optical signal of the current round entering the second circulator is relatively small.

[0076] Secondly, looking clockwise, the link length from the second coupler to the second optical switch accounts for a large portion of the first loop, and the link length from the first circulator to the second optical switch is also very long. If the first optical switch is turned on and the second optical switch is turned off at the same time, the first optical signal from the previous round existing on the transmission path from the first circulator to the second optical switch will be gradually absorbed by the second optical switch, and the first optical signal of the current round will fully enter the first loop until it reaches the second optical switch. Assuming that the length of the first optical signal in the previous round is T1 and the length of the first optical signal in the current round is also T1, then when the first optical signal in the previous round is completely absorbed and cleared by the second optical switch, the first optical signal of the current round will just fully enter the first loop. At this time, if the first optical switch is turned off and the second optical switch is turned on, the first optical signal of the current round can be transmitted in the ring link. Assuming the second optical switch is located at the head of the first loop, for example, on the first branch of the first loop, when the first optical switch is open and the second optical switch is closed, the first optical signal from the previous round will cause significant interference to the second optical signal of the current round entering the second circulator. After the first optical signal from the previous round is completely absorbed and cleared, the first optical switch closes and the second optical switch opens, resulting in fewer first optical signals entering the first loop in the current round. This makes it impossible to achieve the goal of transmitting the first optical signal of a certain duration generated in each round in the ring link.

[0077] Similar to the link setup principle for the first optical signal, the link setup for the second optical signal will be described below.

[0078] After the second optical signal is input into the second loop via the second coupler, it sequentially passes through the second shared link segment, the sixth circulator, the first branch of the second loop, the fifth circulator, the first shared link segment, the fourth circulator, the second branch of the second loop, and the third circulator. The second optical signal output from the third circulator reaches the optical signal receiving component via the second coupler. The second branch of the second loop is located at the end of the second loop, and the third optical switch is located on the second branch of the second loop, that is, at the end of the second loop. This arrangement has two advantages:

[0079] Firstly, looking counterclockwise, the link length from the third optical switch to the second coupler is only a small part of the second loop, and the link length from the third optical switch to the first circulator is also very short. If the third optical switch is closed at the same time as the first optical switch is turned on, the amount of the second optical signal from the previous round on the transmission path between the third optical switch and the first circulator is relatively small. The interference of the second optical signal from the previous round on the first optical signal of the current round entering the first circulator is relatively small.

[0080] Secondly, looking counterclockwise, the link length from the second coupler to the third optical switch accounts for a large portion of the second loop, and the link length from the second circulator to the third optical switch is also very long. If the first optical switch is turned on and the third optical switch is turned off at the same time, the second optical signal from the previous round existing on the transmission path from the second circulator to the third optical switch will be gradually absorbed by the third optical switch, and the second optical signal of the current round will fully enter the second loop until it reaches the third optical switch. Assuming that the length of the second optical signal in the previous round is T1 and the length of the second optical signal in the current round is also T1, then when the second optical signal in the previous round is completely absorbed and cleared by the third optical switch, the second optical signal of the current round will just fully enter the second loop. At this time, the first optical switch is turned off and the third optical switch is turned on, so the second optical signal of the current round can be transmitted in the ring link. Assuming the third optical switch is placed at the head of the second loop, for example, on the first branch of the second loop, and the first optical switch is open while the third optical switch is closed, the second optical signal from the previous round will cause significant interference to the first optical signal of the current round entering the first circulator. After the second optical signal from the previous round is completely absorbed and cleared, the first optical switch is closed and the third optical switch is open, resulting in fewer second optical signals entering the second loop in the current round. This makes it impossible to achieve the goal of transmitting the second optical signal of a certain duration generated in each round in the ring link.

[0081] Furthermore, in one embodiment, the aforementioned ring link further includes a first signal amplifier disposed on the first loop and a second signal amplifier disposed on the second loop.

[0082] In this embodiment, the first signal amplifier disposed on the first circuit and the second signal amplifier disposed on the second circuit are used to amplify the first optical signal and the second optical signal respectively to compensate for the loss of the first optical signal and the second optical signal during transmission.

[0083] Further, in one embodiment, the first signal amplifier includes a first amplifier disposed on a first branch of the first circuit and a third amplifier disposed on a second branch of the first circuit. The first amplifier is also... Figure 1 OA1, the third amplifier, is... Figure 1 OA3 in the middle.

[0084] The aforementioned second signal amplifier includes a fourth amplifier disposed on the first branch of the second circuit and a second amplifier disposed on the second branch of the second circuit. The fourth amplifier is also... Figure 1 OA4, the second amplifier, is... Figure 1 OA2 in the middle.

[0085] In this embodiment, amplifiers are set at the beginning and end of each loop to improve the accuracy and efficiency of amplification.

[0086] Furthermore, in one embodiment, when the first optical signal and the second optical signal are wavelength division multiplexed optical signals, the ring link further includes a first equalizer disposed on the first loop and a second equalizer disposed on the second loop. The first equalizer is also known as... Figure 1 WaveShaper1, the second equalizer, is... Figure 1 WaveShaper2 in the middle.

[0087] In this embodiment, to ensure precise control of optical signal power, an equalizer can be added as needed, typically using a programmable optical filter (WaveShaper).

[0088] Furthermore, in one embodiment, the aforementioned fiber optic ring link further includes:

[0089] The fiber optic ring control signal generator is used to generate a first control signal, a second control signal, a third control signal, and to acquire a trigger signal.

[0090] The first control signal, that is Figure 1 The optical switch control signal 1 is used to control the output of the optical signal transmitting component to the first optical signal and the second optical signal.

[0091] The second control signal, namely Figure 1 The optical switch control signal 2 is used to control the on / off state of the first circuit.

[0092] The third control signal, namely Figure 1 The optical switch control signal 3 is used to control the on / off state of the second circuit.

[0093] The acquisition trigger signal is used to control the optical signal receiving component to receive the first optical signal and the second optical signal.

[0094] In this embodiment, a fiber optic ring control signal generator is used to generate control signals for the entire fiber optic ring link. This can control the number of transmission cycles of the optical signal after it enters the fiber optic ring link, and can also control the acquisition of the optical signal output from the fiber optic ring link.

[0095] Furthermore, in one embodiment, the optical receiving component includes an optical filter connected to a 2-to-1 optical switch and an optical signal receiver (RX) connected to the optical filter. The optical signal receiver is also connected to an optical fiber ring control signal generator.

[0096] In this embodiment, since the transmission link lengths traversed by the optical signals in both directions are the same, the transmission delays are also the same. The circulation time T2 of the optical signal in the ring link is controlled by the optical switch in the ring link, and the corresponding control signal is generated by the fiber optic ring control signal generator. When the bidirectional optical signal circulating in the ring link passes through the 2×2 50:50 second coupler, it is output from both directions respectively. After passing through the two circulators in each direction, it finally reaches the optical signal receiving end.

[0097] At the optical signal receiver, since there are two optical signals, they need to be received separately. First, one of the optical signals is connected via a 2-to-1 optical multiplier. Then, it passes through an optical filter to filter out the wavelength channel to be tested, and finally enters the optical signal receiver. A fiber optic loop control signal generator sends a trigger signal to cause the optical signal receiver to acquire the signal for a specified number of revolutions. In a laboratory environment, the optical signal receiver typically consists of an optical receiver and an oscilloscope. The trigger signal is used as an external trigger source for the oscilloscope. After the oscilloscope acquires the signal for the specified number of revolutions, offline digital signal processing is performed to demodulate the signal.

[0098] Furthermore, in one embodiment, the duration of the optical signal output by the first control signal controlling the first optical signal and the second optical signal is calculated using the following formula (1):

[0099] T1=L / (C / n)(1)

[0100] Where T1 represents the duration of the optical signal, L represents the total length of the ring link, C represents the speed of light in a vacuum, and n represents the refractive index of the optical fiber.

[0101] In this embodiment, the optical signal generated by TX first passes through optical switch 1. The on / off state of optical switch 1 is precisely controlled by the fiber optic loop control signal generator, outputting an optical signal of a fixed duration, denoted as T1. T1 should be the time required for the optical signal to travel one revolution in the fiber optic loop, i.e., T1 = L / (C / n), where L represents the length of the fiber optic loop link, generally expressed as the length of a ring link, C represents the speed of light in a vacuum, and n represents the refractive index of the fiber.

[0102] The generated T1 optical signal is split into two parts, Singal1 and signal2, by a 1×2 50:50 coupler 1. Singal1 is input to port 1 of circulator 1 and output from port 2. Singal2 is input to port 1 of circulator 2 and output from port 2. Then, Singal1 and Singal2 are respectively input to a 2×2 50:50 coupler 2 from opposite directions. Coupler 2 connects the two ends of the ring link, so the Singal1 and Singal2 optical signals will enter the ring link for transmission from clockwise and counterclockwise directions, respectively.

[0103] For Signal1, which is transmitted clockwise, it first enters port 2 of circulator 3, is output from port 3, is amplified by OA1, enters port 1 of circulator 4, is output from port 2, and is transmitted through the fiber optic link. Then it enters port 2 of circulator 5, is output from port 3, is amplified again by the third amplifier OA3, is equalized by WaveShaper1, and then enters port 1 of circulator 6 through optical switch 2, is output from port 2, and returns to coupler 2, completing one cycle of transmission.

[0104] For Signal2, which transmits counterclockwise, it first outputs from port 2 of circulator 6, then from port 3. After being amplified by OA4, it is input to port 1 of circulator 5, then output from port 2, and transmitted through the fiber optic link. Then it is input to port 2 of circulator 4, then from port 3. After being amplified by OA2, it is equalized by WaveShaper2, then through optical switch 3, input to port 1 of circulator 3, then output from port 2, and returns to coupler 2, completing one cycle of transmission.

[0105] Signal1, transmitted clockwise, is input to port 2 of circulator 2 via coupler 2 and output from port 3. Signal2, transmitted counterclockwise, is input to port 2 of circulator 1 via coupler 2 and output from port 3. As required for testing, one of the signals is connected to the optical filter and then reaches the RX for reception.

[0106] In terms of timing control, a fiber optic ring control signal generator produces four signals, referencing... Figure 2 Signal timing diagram of the fiber optic loop control signal generator.

[0107] Optical switch control signal 1: is a high-level signal with a duration of T1, which causes optical switch 1 to generate an optical signal through T1.

[0108] Optical switch control signal 2: The opposite of optical switch control signal 1, it is a low-level signal with a duration of T1. It controls optical switch 2 to block the clockwise propagating optical signal in the fiber optic loop during the time T1 that optical switch 1 is in operation.

[0109] Optical switch control signal 3: The opposite of optical switch control signal 1, but the same as optical switch control signal 2, is a low-level signal with a duration of T1. It controls optical switch 3 to block the counter-clockwise propagating optical signal in the fiber optic loop during the time T1 that optical switch 1 is in operation.

[0110] Acquisition trigger signal: Maintain a time delay T2 with the conduction time of optical switch control signal 1. T2 is calculated based on the number of cycles of the signal to be received. For example, in the Nth cycle, considering the case of rising edge triggering, then T2 = N * T1, and the signal acquired by RX trigger is the optical signal after transmitting a distance of N * L.

[0111] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0112] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0113] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0114] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0115] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0116] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0117] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A fiber ring link suitable for bidirectional communication, characterized in that, The fiber optic ring link includes: An optical signal transmitting component, which is used to output a first optical signal and a second optical signal; An optical signal receiving component, used to receive a first optical signal and a second optical signal; The second coupler is used to receive the first optical signal and the second optical signal output by the optical signal transmitting component and transmit them to the first circuit and the second circuit respectively. It is also used to receive the first optical signal and the second optical signal output by the first circuit and the second circuit and transmit them to the optical signal receiving component respectively. The first loop and the second loop are connected in parallel through multiple circulators to form a ring link. In this ring link, the transmission directions of the first optical signal and the second optical signal are split by the multiple circulators so that the first optical signal and the second optical signal are transmitted in the clockwise and counterclockwise directions of the ring link, respectively. The ring link includes a third circulator, a fourth circulator, a fifth circulator, and a sixth circulator connected in sequence. A first branch of a first circuit and a second branch of a second circuit are connected in parallel between the third circulator and the fourth circulator. A first shared link segment of the first circuit and the second circuit is connected between the fourth circulator and the fifth circulator. A second branch of the first circuit and a first branch of the second circuit are connected in parallel between the fifth circulator and the sixth circulator. A second shared link segment of the first circuit and the second circuit is connected between the sixth circulator and the third circulator. The length of the first shared link is greater than the length of the second shared link. The ring link also includes a second optical switch in the second branch of the first loop and a third optical switch in the second branch of the second loop.

2. The fiber ring link suitable for bidirectional communication as set forth in claim 1, wherein, The optical signal transmitting component includes: The optical signal transmitter is used to generate the raw optical signal; The first optical switch is connected to the optical signal transmitter and is used to control the output of the original optical signal; The first coupler, which is connected to the first optical switch, is used to split the original optical signal into a first optical signal and a second optical signal before outputting them.

3. The fiber loop link suitable for bidirectional communication as set forth in claim 1, wherein, The fiber optic ring link also includes: The first circulator is connected to the optical transmitting component, the optical receiving component and the second coupler. It is used to receive the first optical signal output by the optical transmitting component, adjust its direction and transmit it to the first loop through the second coupler. It is also used to receive the second optical signal output by the second loop through the second coupler, adjust its direction and transmit it to the optical receiving component. The second circulator connects the optical transmitting component, the optical receiving component, and the second coupler. It is used to receive the second optical signal output by the optical transmitting component, adjust its direction, and transmit it to the second loop through the second coupler. It is also used to receive the first optical signal output by the first loop through the second coupler, adjust its direction, and transmit it to the optical receiving component.

4. The fiber loop link suitable for bidirectional communication as set forth in claim 3, wherein, The fiber optic ring link also includes: A 2-to-1 optical switch is connected to a first circulator, a second circulator, and an optical signal receiving component. It is used to select one of the first optical signal and the second optical signal output from the first circulator and the second circulator at the same time and send it to the optical signal receiving component.

5. The fiber loop link suitable for bidirectional communications as set forth in claim 1, wherein, The ring link also includes a first signal amplifier disposed on the first loop and a second signal amplifier disposed on the second loop.

6. The fiber optic ring link suitable for bidirectional communication as described in claim 5, characterized in that, The first signal amplifier includes a first amplifier disposed on a first branch of the first circuit and a third amplifier disposed on a second branch of the first circuit; The second signal amplifier includes a fourth amplifier disposed on the first branch of the second circuit and a second amplifier disposed on the second branch of the second circuit.

7. The fiber optic ring link suitable for bidirectional communication as described in claim 1, characterized in that, When the first optical signal and the second optical signal are wavelength division multiplexed optical signals, the ring link further includes a first equalizer disposed on the first loop and a second equalizer disposed on the second loop.

8. The fiber optic ring link suitable for bidirectional communication as described in claim 1, characterized in that, The fiber optic ring link also includes: A fiber optic loop control signal generator is used to generate a first control signal, a second control signal, a third control signal, and to acquire a trigger signal. The first control signal is used to control the output of the optical signal transmitting component to the first optical signal and the second optical signal; The second control signal is used to control the on / off state of the first circuit; The third control signal is used to control the on / off state of the second circuit; The acquisition trigger signal is used to control the optical signal receiving component to receive the first optical signal and the second optical signal.

9. The fiber optic ring link suitable for bidirectional communication as described in claim 8, characterized in that, The duration of the optical signals output by the first control signal, which controls the first optical signal and the second optical signal, is calculated using the following formula: T1 = L / (C / n) in, T1 represents the duration of the optical signal; L represents the total length of the ring link; C represents the speed of light in a vacuum; n represents the refractive index of the fiber core.

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