WO2014000149A1

WO2014000149A1 - Optical transceiver module, optical communication system and optical signal transmitting-receiving method

Info

Publication number: WO2014000149A1
Application number: PCT/CN2012/077485
Authority: WO
Inventors: 周恩宇; 刘德坤; 徐之光
Original assignee: 华为技术有限公司
Priority date: 2012-06-25
Filing date: 2012-06-25
Publication date: 2014-01-03
Also published as: CN102870352B; CN102870352A

Abstract

An optical transceiver module, an optical communication system and an optical signal transmitting-receiving method. The optical transceiver module includes a first polarization gain device (1), a Faraday rotator (2), and a second polarization gain device (3). The first polarization gain device (1) is used for emitting the light signals; the Faraday rotator (2) is used for changing the polarization direction of the optical signals, enabling the optical signals not to be saturated when passing through the second polarization gain device (3); the second polarization gain device (3) is used for outputting the optical signals from the Faraday rotator (2), receiving the return optical signals reflected back by the Faraday rotating mirror (5), and outputting the return optical signals to the Faraday rotator (2) after the return optical signals reach saturation; and the Faraday rotator (2) is also used to change the polarization direction of the return optical signals, so that the return optical signals are amplified on the gain in the first polarization gain device (1). The optical transceiver module achieves smooth transmission of the optical signals and the information erasing and returning of the return optical signals with a simple structure and low cost.

Description

Optical transceiver module, optical communication system and optical signal transmitting and receiving method

Technical field

The present invention belongs to the field of communications, and in particular, to an optical transceiver module, an optical communication system, and an optical signal transmitting and receiving method.

Background technique

As users' demand for network bandwidth continues to increase, traditional copper broadband access systems are increasingly facing bandwidth bottlenecks. At the same time, with the maturity of fiber-optic communication technologies with huge bandwidth capacity, application costs have been declining year by year, making fiber access networks a strong competitor for next-generation broadband access networks. Among them, PON (Passive Optical The low cost advantage of Network, Passive Optical Network makes it more competitive. According to different PON implementations, they can be divided into different types, which are based on ATM (Asynchronous Transfer Mode, Asynchronous Transfer Mode) ATM-PON, Ethernet-based EPON (Ethernet over PON), GPON (Gigabit Passive Optical Network) with Gigabit rate, using WDM (Wave) Division Multiplexing, WDM-PON, and OCDMA (Optical Code Division Multiple) Addressing, optical code division multiple access) OCDDA-PON.

At present, in many fiber access network solutions, WDM-PON has attracted much attention due to its greater bandwidth capacity and information security similar to peer-to-peer communication. However, compared with the optical access network solutions such as EPON and GPON, the cost of WDM-PON is very high. Among them, the light source is the most influential factor in the cost of WDM-PON. In the existing WDM-PON system, there are two solutions of a colored light source and a colorless light source. In a colored light source solution, each ONU (Optical Network Unit, Optical Network Unit) AWG (Array Waveguide Grating) or WGR (Waveguide) connected to the transceiver module Grating Router, Waveguide Grating Router) The wavelengths on the ports are different, so that the ONUs of the users are different and cannot be used in common. In addition, it is very difficult for the service provider to issue services. When the operator issues an ONU to the user, it is necessary to predict the fiber connection of the user. Which port is the AWG or WGR, the actual operation is very inconvenient; and it will also bring storage problems to operators.

The so-called colorless light source means that the ONU transceiver module does not vary depending on the wavelength of the connected port. The laser emission wavelength can automatically adapt to the wavelength of the connected AWG or WGR port, which can be realized on any AWG or WGR port. Plug and play. In the prior art, the wavelength is adaptively implemented by inverting the output optical signal portion to re-inject into the laser for remodulation. However, in this manner, the remodulated signal not only carries the remodulated signal but also carries The original signal causes the eye diagram to deteriorate and the bit error rate to deteriorate.

One of the existing solutions is shown in Figure 1, using SOA (Semiconductor Optical Amplifier, semiconductor optical amplifier) A scheme that erases old data and remodulates it. Among them, ONU is composed of SOA101, receiver 102 and OM103 (Optical Modulator, light modulator). After the downlink data passes through the SOA101, due to the saturation gain characteristic of the SOA101, the optical power of the 0,1 data is substantially equal, thereby erasing the original data and remodulating the signal through the OM103, thereby erasing the data and remodulating the data. but, The scheme adopts a double-fiber bidirectional structure, and it is unacceptable to adopt double fiber in engineering laying; in addition, although the scheme can be improved, a single-fiber bidirectional structure is adopted, but an optical circulator needs to be added to each ONU. This greatly increases the cost of the ONU and is also difficult to accept.

technical problem

An object of the embodiments of the present invention is to provide an optical transceiver module, which aims to solve the problem of BER degradation caused by self-injection remodulation in a simple and cost-effective manner, and improve the quality of the remodulated signal.

Technical solution

The embodiment of the present invention is implemented as follows. An optical transceiver module includes a first polarization gain device, a Faraday rotator, and a second polarization gain device, wherein:

The first polarization gain device is configured to emit an optical signal;

The Faraday rotator for changing a polarization direction of the optical signal such that the optical signal is not saturated when passing through the second polarization gain device;

The second polarization gain device is configured to output an optical signal from the Faraday rotator and receive a return optical signal reflected by the Faraday rotating mirror, and after the return optical signal is saturated, rotate to the Faraday Output

The Faraday rotator is further configured to change a polarization direction of the return optical signal such that the return optical signal is gain amplified in the first polarization gain device.

Another object of the embodiments of the present invention is to provide an optical communication system including an optical line terminal and an optical network unit, where the optical line terminal and/or the optical network unit includes the optical transceiver module described above.

Another object of the embodiments of the present invention is to provide an optical signal transceiving method, the method comprising the following steps:

Transmitting an optical signal by the first polarization gain device;

Changing a polarization direction of the optical signal by a Faraday rotator and outputting to the second polarization gain device such that the optical signal is not saturated when passing through the second polarization gain device;

Reflecting an optical signal output by the second polarization gain device and changing a polarization direction of the optical signal to form a return optical signal and injecting a second polarization gain device, so that the return optical signal is saturated when passing through the second polarization gain device ;

The polarization direction of the return optical signal is varied by a Faraday rotator and output to the first polarization gain device such that the return optical signal is gain amplified in the first polarization gain device.

Beneficial effect

The embodiment of the invention utilizes the gain characteristic of the polarization gain device, and realizes the generation and transmission of the optical signal and the information erasing and returning of the returned optical signal by the cooperation of the Faraday rotator, thereby solving the error caused by the self-injection remodulation. The problem of code rate deterioration effectively improves the quality of the remodulated signal; and the information erasing and returning of the optical signal generation, transmission and return optical signals are implemented in the same channel, and no separate transmission channel for returning the optical signal is required. There is no need to add complicated control circuits, and there is no need to add expensive components such as optical fibers and optical circulators. The structure is simple, small in size, and low in cost. In addition, the optical transceiver module can be bidirectionally transmitted using a single fiber, which is suitable for engineering laying. In the middle, you can effectively control the networking cost.

DRAWINGS

1 is a schematic diagram of an optical module for erasing data using SOA in the prior art;

2 is a schematic diagram of an optical transceiver module according to a first embodiment of the present invention;

3 is a schematic diagram of data erasure of an optical transceiver module according to a first embodiment of the present invention;

4 is a schematic diagram showing the operation of an optical transceiver module according to a first embodiment of the present invention;

FIG. 5 is a schematic diagram of an optical communication system for applying an optical transceiver module according to a first embodiment of the present invention; FIG.

6 is a schematic partial structural diagram of an optical transceiver module according to a first embodiment of the present invention;

7 is a schematic diagram of an optical communication system according to a second embodiment of the present invention;

FIG. 8 is a flowchart of a method for transmitting and receiving an optical signal according to a third embodiment of the present invention.

Embodiments of the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The specific implementation of the present invention is described in detail below in conjunction with specific embodiments:

Embodiment 1:

FIG. 2 is a schematic structural diagram of an optical transceiver module according to a first embodiment of the present invention. For convenience of description, only parts related to the embodiment are shown.

The optical transceiver module mainly includes a first polarization gain device 1, a Faraday rotator 2, and a second polarization gain device 3. Wherein, the first polarization gain device 1 is for emitting an optical signal. The Faraday rotator 2 and the second polarization gain device 3 are sequentially disposed on the transmission path of the optical signal.

The first polarization gain device 1 emits a linearly polarized optical signal, and specifically, a polarization gain laser can be used. It can be understood that the first polarization gain device 1 of FIG. 2 adopts RSOA, which is only an optional solution. The first polarization gain device 1 is not limited to the RSOA, and other lasers having polarization gain characteristics or the like may be employed. Other devices are also not limited to those shown in the figures.

In the optical transceiver module, The first polarization gain device 1 can gain-amplify the injected excitation light and be modulated by the corresponding electrical signal to emit a linearly polarized optical signal carrying the corresponding information, the polarization direction of the optical signal and the first polarization gain device 1 The direction of maximum gain is parallel.

The Faraday rotator 2 has a rotational effect on the linearly polarized incident light, rotating the polarization direction of the linearly polarized light by a certain angle, and the specific rotation angle is related to the frequency of the incident light and the length of the transmission path in the rotator. In the embodiment of the present invention, if the ray polarized light is to be rotated by a preset angle, the thickness of the Faraday rotator 2 can be determined in advance according to the frequency of the incident light and the preset rotation angle to control the transmission of the incident light therein. The length of the path, which in turn causes its polarization direction to rotate by a preset angle.

The first and second polarization gain devices have special gain characteristics, and the gain effects are different for incident light of different polarization directions. Each polarization gain device has an inherent direction of maximum gain and minimum gain, wherein the gain is maximum/ The smallest direction refers to the polarization direction of the linearly polarized light that causes the polarization gain device to be in the maximum/minimum gain state. Generally, the angle between the gain of the polarization gain device and the direction of the smallest gain is 90°. In addition, when the light energy transmitted therein reaches a certain level, the gain saturation state is reached, and the output light power is kept constant, as shown in FIG. Therefore, when the polarization direction of the incident ray polarized light is exactly parallel to the direction in which the gain of the polarization gain device is maximized, the saturation state is most easily reached. When the polarization direction of the incoming ray polarized light is parallel to the direction in which the gain is minimized, it is most difficult to saturate.

The embodiment of the invention realizes the information erasing and returning of the optical signal generation and output and the return optical signal based on the above module. The working principle of the optical transceiver module will be described in detail below with reference to FIG. 4:

The first polarization gain device 1 emits a linearly polarized optical signal L1, and the Faraday rotator 2 rotates the polarization direction of the optical signal L1 by a certain angle so that the changed polarization direction and the gain of the second polarization gain device 3 are smaller or minimum. The direction is parallel. Then, the optical signal L1 is input to the second polarization gain device 3, and since its polarization direction is parallel to the direction in which the gain of the second polarization gain device 3 is small or smallest, the gain is small and is not easily saturated, and the carried 0, 1 The optical power of the data changes in proportion, and the information is not erased, so that the optical signal can be transmitted smoothly. The optical signal L1 is outputted to the receiving end via the second polarization gain device 3. At the same time, a part of the optical signal is reflected to form a return optical signal L2, and its polarization direction is changed by 90°, and the changed polarization direction is parallel to the direction in which the gain of the second polarization gain device 3 is larger or larger.

The return optical signal L2 is returned to the second polarization gain device 3 along the original path. Since the polarization direction of the return optical signal L2 is parallel to the direction in which the gain of the second polarization gain device 3 is large or largest. At this time, although the return optical signal L2 is weak, the return optical signal can be saturated, so that the optical power corresponding to the 0, 1 data is substantially equal, so that the information carried by the return optical signal L2 is erased. The return light signal L2 of the erased information passes through the Faraday rotator 2 again, and its polarization direction is rotated again. The polarization direction after the rotation is parallel to the direction in which the gain of the first polarization gain device 1 is large or largest, so that the return light signal L2 is The first polarization gain device 1 is gain-amplified to generate an optical signal again.

In summary, the optical transceiver module provided by the embodiment of the present invention uses the first polarization gain device 1, the Faraday rotator 2, and the second polarization gain device 3 to construct a transmission channel, in which the generation and output of the optical signal L1 are realized and Returns the erasure of the optical signal L2. On the one hand, the problem of deterioration of the bit error rate due to self-injection remodulation is solved, and the quality of the remodulated signal is effectively improved. On the other hand, the transmission of the optical signal L1 and the information erasing and returning of the return optical signal L2 are implemented in the same channel, and there is no need to separately provide a return channel for returning the optical signal L2, and no complicated control circuit is required, nor is it necessary to add a complicated control circuit. Need to increase the components such as optical fiber and optical circulator, the structure is simple, the volume is small, and the cost is low. In addition, the optical transceiver module of the embodiment of the invention can be bidirectionally transmitted by using a single fiber, which is suitable for engineering laying, and can effectively control the laying cost.

In the embodiment of the present invention, the Faraday rotator 2 and the first polarization gain device 1 and the second polarization gain device 3 are both transmitted by means of spatial optical coupling.

Further, an optical coupling lens 4 may be disposed between the Faraday rotator 2 and the first polarization gain device 1 and the second polarization gain device 3 for accurately coupling the optical signal into the corresponding device.

In the embodiment of the present invention, the optical signal outputted through the second polarization gain device 3 can be reflected back through the Faraday rotating mirror 5 in the optical network, and the polarization direction thereof is changed during the reflection process, as shown in FIG. 4 and FIG. The optical signal forms an intracavity laser resonance between the Faraday rotator 5 and the first polarization gain device 1. Of course, the Faraday rotator 5 is a partial mirror that, in addition to reflecting a portion of the optical signal, outputs another portion of the optical signal to the receiving end.

With further reference to FIG. 5, the optical signal outputted through the second polarization gain device 3 can be multiplexed by a multiplexing and demultiplexing unit 6 and transmitted to the Faraday rotator mirror 5. It can be understood that the optical transceiver module is connected to the branch port 62 of the multiplexing and demultiplexing unit 6, and the Faraday rotating mirror 5 is connected to the common port 61 of the multiplexing and demultiplexing unit 6.

In the embodiment of the present invention, the optical transceiver module further includes a receiver 7 for receiving an optical signal, and the receiver 7 and the second polarization gain device 3 are connected in common to a wavelength division multiplexer (WDM) 8. A sub-multiplexer (WDM) 8 can be connected to the branch port 62 of the multiplexing and demultiplexing unit 6 to implement connection of the optical transceiver module to the multiplexing and demultiplexing unit 6.

In the embodiment of the present invention, the multiplexing and demultiplexing unit 6 and the Faraday rotating mirror 5 and the second polarization gain device 3 can be connected by an optical fiber. The Faraday rotating mirror 5 can avoid the influence of the birefringence effect of the optical fiber on the polarization state of the optical signal, so that the return optical signal still maintains a specific linear polarization direction before being injected into the second polarization gain device 3 through the optical fiber.

As a preferred embodiment of the present invention, the angle between the first polarization gain device 1 and the direction in which the gain of the second polarization gain device 3 is maximized is 45°. Further, the thickness of the Faraday rotator 2 can be appropriately designed according to the frequency of the optical signal, so that the Faraday rotator 2 rotates the polarization direction of the optical signal and the return optical signal by 45°. Since the angle between the maximum and minimum directions of the gain of the second polarization gain device 3 is 90°, the maximum gain direction of the first polarization gain device 1 and the gain minimum direction of the second polarization gain device 3 are also 45°. angle. When the Faraday rotator 2 rotates the polarization direction of the optical signal by 45°, its polarization direction is exactly the same as the direction in which the gain of the second polarization gain device 3 is the smallest, so that the optical signal can be smoothly output. The polarization direction of the returning optical signal is rotated by 90°, and is exactly the same as the direction in which the gain of the second polarization gain device 3 is maximized, so that the information carried thereby is erased.

With further reference to Figure 6, it will be appreciated that the core components of the first polarization gain device 1 and the second polarization gain device 2 are both gain media, with the direction of maximum gain being generally parallel to the surface of the gain medium. Therefore, the gain medium (the first medium 11) in the first polarization gain device 1 and the gain medium (the second medium 31) in the second polarization gain device 3 can be presented by rational design of the base 601 carrying the gain medium. The 45° is placed so that the surfaces of the two are at an angle of 45° to ensure that the maximum gain of the two is at an angle of 45°.

Of course, if the first medium 11 and the second medium 31 are irregular shapes, the relative orientations of the first medium 11 and the second medium 31 can be reasonably adjusted to ensure the gains of the first polarization gain device 1 and the second polarization gain device 3. The maximum direction is 45°.

It can be understood that there are two ways of placing the first medium 11 and the second medium 31 at 45°, that is, 45° in the clockwise or counterclockwise direction, and the two conditions may cause the polarization direction of the optical signal L1 to be The direction in which the polarization of the second polarization gain device 3 is maximum or the smallest is parallel. In order to ensure that the information to be output is not erased, the present embodiment needs to make the polarization direction of the optical signal L1 parallel to the direction in which the gain of the second polarization gain device 3 is minimized. Therefore, the orientation of the second medium 31 can be rationally designed according to the direction of rotation of the predicted optical signal in the Faraday rotator 2, so that the polarization direction of the optical signal L1 after passing through the Faraday rotator 2 is exactly the same as that of the second medium 31. The direction of the smallest gain is parallel to ensure smooth signal transmission.

The above preferred embodiment defines the orientation of the first medium 11 and the second medium 31 and the rotation angle of the Faraday rotator 2 such that the gain of the optical signal L1 in the second polarization gain device 3 is minimized, so that the return light The gain of the signal L2 in the second polarization gain device 3 is maximized, further optimizing the quality of the optical signal L1 and the return optical signal L2. Also, the optical signal injected back to the first polarization gain device 1 is exactly parallel to the direction in which the gain of the first polarization gain device 1 is maximized, so that the return optical signal L2 achieves maximum gain in the first polarization gain device 1, so that the generated optical signal is generated. Has the highest energy, which in turn improves communication quality.

Further preferably, the first polarization gain device 1, the Faraday rotator 2 and the second polarization gain device 3 may be integrated to reduce the volume of the optical module. Moreover, the above three devices are the core parts of the module, and if the orientation of any one of the devices changes, the network performance is affected. In the embodiment of the present invention, the three devices are integrated to make it more stable on the one hand, and the other is more stable. It is also easy to disassemble and repair during use to facilitate product maintenance.

In the embodiment of the present invention, the first polarization gain device 1 can adopt RSOA, and can also use the injection of the front end surface reflection to lock the polarization gain. FP-LD (injection-locked FP-LD, injection-locked Fabry-Perot laser), or other polarization gain type laser, can be reasonably selected according to actual needs.

In the embodiment of the present invention, the second polarization gain device 3 may employ SOA or other devices having polarization gain characteristics.

In the embodiment of the present invention, the multiplexing and demultiplexing unit 6 may adopt an AWG or a WGR.

Embodiment 2:

Fig. 7 is a view showing an optical communication system according to a second embodiment of the present invention, and for convenience of explanation, only parts related to the present embodiment are shown.

The optical communication system includes an optical line terminal 71 and an optical network unit 72, and the optical line terminal 71 and/or the optical network unit 72 includes the optical transceiver module described above. FIG. 7 shows a case where both the optical line terminal 71 and the optical network unit 72 include an optical transceiver module.

Further, the system further includes a Faraday rotating mirror 73 that reflects the optical signal from the optical transceiver module and changes its polarization direction by 90° to form a return optical signal.

Further, the system further provides a multiplexing and demultiplexing unit 74 on the optical line terminal 71 and the optical network unit 72 side to implement wavelength division multiplexing. The common ports 741 of the two multiplexing and demultiplexing units 74 are connected by a trunk optical fiber 75, and the branch ports 742 are respectively connected to the optical line terminal 71 and the optical network unit 72. When the Faraday rotator mirror 73 is provided on the optical line terminal 71 and/or the optical network unit 72 side, the Faraday rotator mirror 73 is directly connected to the common port 741 of the multiplexing and demultiplexing unit 74.

Embodiment 3:

FIG. 8 is a flow chart showing a method for transmitting and receiving an optical signal according to a third embodiment of the present invention. For convenience of explanation, only parts related to the present embodiment are shown.

In step S301, an optical signal is emitted by the first polarization gain device.

In this embodiment, the first polarization gain device may be a polarization gain laser, and the optical signal is in a linear polarization state.

In step S302, the polarization direction of the optical signal is changed by the Faraday rotator and output to the second polarization gain device such that the optical signal is not saturated when passing through the second polarization gain device.

In this embodiment, the Faraday rotator changes the polarization direction of the optical signal by a predetermined angle so that the changed polarization direction is parallel to the direction in which the gain of the second polarization gain device is smaller or smallest, thereby preventing the optical signal from being saturated and making the light The signal can be output smoothly.

In step S303, the optical signal output by the second polarization gain device is reflected and the polarization direction of the optical signal is changed, a return optical signal is formed and injected into the second polarization gain device, so that the return optical signal is passed through the second polarization gain device. saturation.

In this embodiment, the optical signal output by the second polarization gain device can be reflected by the Faraday rotating mirror in the optical network, and the polarization direction thereof is rotated by 90° during the reflection process, so that the changed polarization direction is The gain of the second polarization gain device is greater or the direction of the maximum is parallel, causing the return optical signal to be saturated in the second polarization gain device, thereby erasing the data.

In step S304, the polarization direction of the return optical signal is changed by the Faraday rotator and output to the first polarization gain device, so that the return optical signal is gain-amplified in the first polarization gain device.

In this embodiment, the Faraday rotator changes the polarization direction of the returned optical signal of the erased data by a predetermined angle so as to be parallel to the direction in which the gain of the first polarization gain device is larger or larger, thereby ensuring that the return optical signal is The first polarization gain device is gain amplified to regenerate the optical signal, which is again transmitted in accordance with the above steps, and so on.

The method utilizes the characteristics of the polarization gain device and the Faraday rotator to achieve the generation and output of the optical signal and the erasure of the return optical signal. The problem of deterioration of the bit error rate due to self-injection remodulation is solved, and the quality of the remodulated signal is effectively improved. Moreover, the information transmission and return signal transmission of the optical signal and the return optical signal are implemented in the same channel, and there is no need to separately provide a return channel for returning the optical signal, no complicated control circuit is added, and no optical fiber or optical ring is needed. The components such as the row device are simple in structure, small in size, and low in cost.

Preferably, the polarization direction of the optical signal outputted by the Faraday rotator is the same as the direction in which the gain of the second polarization gain device is the smallest, so that the gain of the optical signal is minimized, and the optical signal can be smoothly outputted. At the same time, the polarization direction of the return optical signal injected into the second polarization gain device can be made the same as the direction in which the gain of the second polarization gain device is maximized, so that the gain of the return optical signal is maximized to maximize the gain to ensure that it reaches Saturated to erase data. In order to achieve the above effects, the first polarization gain device 1, the second polarization gain device 3, and the Faraday rotator 2 can be correspondingly designed according to the solution described in the first embodiment, and details are not described herein again.

The optical transceiver module and the optical signal transmitting and receiving method provided by the embodiments of the present invention not only realize the wavelength adaptation, but also avoid the problem of the BER degradation caused by the self-injection remodulation, improve the network performance, and the structure of the optical transceiver module. Simple, low cost, easy to maintain, suitable for promotion.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

An optical transceiver module, comprising: a first polarization gain device, a Faraday rotator, and a second polarization gain device, wherein:

The first polarization gain device is configured to emit an optical signal;

The Faraday rotator for changing a polarization direction of the optical signal such that the optical signal is not saturated when passing through the second polarization gain device;

The second polarization gain device is configured to output an optical signal from the Faraday rotator and receive a return optical signal reflected by the Faraday rotating mirror, and after the return optical signal is saturated, rotate to the Faraday Output

The Faraday rotator is further configured to change a polarization direction of the return optical signal such that the return optical signal is gain amplified in the first polarization gain device.
The optical transceiver module of claim 1 wherein said first polarization gain device is a polarization gain laser.
The optical transceiver module according to claim 1, wherein an optical coupling lens is disposed between the Faraday rotator and the first polarization gain device and the second polarization gain device for implementing the Faraday Light transmission between the rotator and the first polarization gain device and the second polarization gain device.
The optical transceiver module according to claim 1, wherein a polarization direction of the optical signal in which the first polarization gain device is in the maximum gain state and a polarization direction of the optical signal in which the second polarization gain device is in the maximum gain state are provided. The angle is 45°.
The optical transceiver module according to any one of claims 1 to 4, wherein the first polarization gain device, the Faraday rotator and the second polarization gain device are integrated.
An optical communication system comprising an optical line terminal and an optical network unit, characterized in that the optical line terminal and/or the optical network unit comprise an optical transceiver module according to any one of claims 1 to 5.
The optical communication system according to claim 6 further comprising a Faraday rotator mirror for changing a polarization direction of the optical signal from the optical transceiver module by 90° and reflecting to form a return optical signal, The return optical signal is saturated as it passes through the second polarization gain device of the optical transceiver module.
An optical signal transceiving method, characterized in that the method comprises the following steps:

Transmitting an optical signal by the first polarization gain device;

Changing a polarization direction of the optical signal by a Faraday rotator and outputting to the second polarization gain device such that the optical signal is not saturated when passing through the second polarization gain device;

Reflecting an optical signal output by the second polarization gain device and changing a polarization direction of the optical signal to form a return optical signal and injecting a second polarization gain device, so that the return optical signal is saturated when passing through the second polarization gain device ;

The polarization direction of the return optical signal is varied by a Faraday rotator and output to the first polarization gain device such that the return optical signal is gain amplified in the first polarization gain device.
The method of claim 8 wherein the polarization direction of the optical signal output by the Faraday rotator is the same as the polarization direction of the optical signal that causes the second polarization gain device to be in a minimum gain state;

The polarization direction of the return optical signal injected into the second polarization gain device is the same as the polarization direction of the optical signal that causes the second polarization gain device to be in the maximum gain state.
A method according to claim 8 or claim 9, wherein said method reflects the optical signal output by said second polarization gain device by a Faraday rotator and changes the polarization direction of said optical signal.