Single-fiber bidirectional transmission processing method and device

Abstract

The application provides a single-fiber bidirectional transmission processing method and device, and relates to the technical field of communication. The method comprises the following steps: acquiring light wave complex amplitude spatial distribution information of a first optical signal and light wave complex amplitude spatial distribution information of a second optical signal transmitted by a multi-plane optical conversion device; and determining a phase template pattern of each phase template of a phase substrate in the multi-plane optical conversion device according to the light wave complex amplitude spatial distribution information of the first optical signal and the light wave complex amplitude spatial distribution information of the second optical signal. According to the scheme of the application, the phase template pattern is determined so that the complex amplitude distribution of the first signal light and the complex amplitude distribution of the second signal light simultaneously meet the power distribution and mode multiplexing functions, thereby supporting single-fiber bidirectional transmission, reducing the uplink power loss of the second optical signal on the basis of not changing the existing passive optical network architecture, and improving the overall performance of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication technology, in particular to a single-fiber bidirectional transmission processing method and device. BACKGROUND

[0002] Passive optical network is a whole set of system using the broadband characteristics of optical fiber and optical device to provide high-quality and reliable communication access service for users, which is generally composed of optical line terminal (OLT) at the station end and optical network unit (ONU) at the user end. In order to reduce the cost, multiple ONUs are connected to the OLT through optical splitters in a tree network topology, sharing the optical fiber bandwidth between the OLT and the optical splitter. For time-division multiplexing (TDM) mechanism, the downlink communication from the OLT to the ONUs adopts a broadcast mode, while the uplink communication from the ONUs to the OLT adopts a time-division multiplexing mode of time slot application-distribution to share the bandwidth. The splitter converges data (carried on the optical carrier) from different users into the transmission optical fiber, and broadcasts the data from the OLT transmitted through the transmission optical fiber to all users.

[0003] However, the additional power loss cannot be avoided when converging the uplink signals, which is specifically manifested as follows: the signal light emitted by each user is reduced to 1 / N of the original power after passing through the power splitter into the transmission optical fiber, where N is the number of branches of the power splitter. For a power splitter with a branch number of 64, 98% of the power of the signal light is lost after passing through the power splitter, and only less than 2% of the power remains, which is a huge waste of energy, and the waste is more serious as N increases. SUMMARY

[0004] The purpose of the present application is to provide a single-fiber bidirectional transmission processing method and device, which can reduce the additional power loss of the uplink signal of the single-fiber bidirectional transmission.

[0005] To achieve the above purpose, the embodiment of the present application provides a single-fiber bidirectional transmission processing method, comprising:

[0006] obtaining the light wave complex amplitude spatial distribution information of a first optical signal and the light wave complex amplitude spatial distribution information of a second optical signal transmitted by a multi-plane optical transformation device; wherein the first optical signal is an optical signal sent by an optical line terminal (OLT), and the second optical signal is an optical signal sent by an optical network unit (ONU);

[0007] determining the phase template pattern of each phase template of a phase substrate in the multi-plane optical transformation device according to the light wave complex amplitude spatial distribution information of the first optical signal and the light wave complex amplitude spatial distribution information of the second optical signal.

[0008] Optionally, the determining the pattern of each phase template of the phase substrate of the multi-plane light transforming device according to the light wave complex amplitude spatial distribution information of the first light signal and the light wave complex amplitude spatial distribution information of the second light signal comprises:

[0009] setting each phase template of the phase substrate as a specific pattern;

[0010] obtaining the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template according to the light wave complex amplitude spatial distribution information of the first light signal and the light wave complex amplitude spatial distribution information of the second light signal; wherein n is the number of phase templates of the phase substrate;

[0011] obtaining the third complex amplitude distribution corresponding to the nth phase template according to the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template;

[0012] determining the phase template pattern of the nth phase template according to the third complex amplitude distribution corresponding to the nth phase template;

[0013] sequentially obtaining the first complex amplitude distribution, the second complex amplitude distribution and the third complex amplitude distribution corresponding to the remaining n-1 phase templates;

[0014] determining the phase template pattern of the remaining n-1 phase templates according to the third complex amplitude distribution corresponding to the remaining n-1 phase templates;

[0015] The first complex amplitude distribution is the complex amplitude distribution before the first light signal propagates to the corresponding phase template; the second complex amplitude distribution is the complex amplitude distribution before the second light signal propagates to the corresponding phase template; and the third complex amplitude distribution is the expected superimposed complex amplitude distribution of the first light signal and the second light signal propagating to the corresponding phase template.

[0016] Optionally, the first complex amplitude distribution, the second complex amplitude distribution and the third complex amplitude distribution corresponding to the mth phase template of the remaining n-1 phase templates are determined in the case that the phase template patterns of the m+1th phase template to the nth phase template have been determined; wherein m is an integer greater than or equal to 1 and less than n.

[0017] Optionally, the obtaining the third complex amplitude distribution corresponding to the nth phase template according to the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template comprises:

[0018] subtracting and accumulating the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template from a target value to obtain the third complex amplitude distribution;

[0019] The target value is a spatial distribution of an LP mode electric field inherent to the few-mode fiber.

[0020] Optionally, the method further comprises:

[0021] Optionally, the method further comprises:

[0022] Optionally, the method further comprises:

[0023] In the case that the wavelength of the first optical signal and the wavelength of the second optical signal are different, the accumulated result is processed based on a specific wavelength.

[0024] Optionally, the method further comprises:

[0025] After the phase mask pattern of all phase masks is determined for the p-th time, the determination of the phase mask pattern of the phase mask is restarted.

[0026] Optionally, p is less than a specific value, or the performance index corresponding to the phase mask pattern determined for the p-th time does not satisfy a performance threshold.

[0027] Optionally, the method further comprises:

[0028] A correction value of a target second optical signal is obtained, wherein the target second optical signal is a second optical signal with a power value greater than a first value.

[0029] The optical power of the optical signal output by the multi-plane optical transformation device after the target second optical signal is input into the multi-plane optical transformation device is corrected according to the correction value.

[0030] According to the corrected optical power, the optical wave complex amplitude spatial distribution information of the second optical signal is updated, and the phase mask pattern of all phase masks is updated.

[0031] Optionally, the method further comprises:

[0032] The correction value of the target second optical signal is obtained by dividing the power value of the target second optical signal by the average power value of the optical signals sent by all ONUs and then subtracting 1, and then multiplying by a control factor.

[0033] Optionally, the method further comprises:

[0034] Normalizing the optical power of the output optical signal to obtain a normalized power;

[0035] According to the normalized power, the correction value and a control factor, a correction power of the output optical signal is calculated.

[0036] Optionally, the multi-plane optical transformation device comprises a first input / output end, a second input / output end, the phase substrate and a plane mirror parallel to the phase substrate.

[0037] The first input / output end is connected to an OLT, and the second input / output end is connected to an ONU.

[0038] Optionally, the specific pattern is a non-fixed pattern.

[0039] To achieve the above object, an embodiment of the present application provides a single-fiber bidirectional transmission processing device, comprising:

[0040] A first acquisition module is configured to acquire optical wave complex amplitude spatial distribution information of a first optical signal and optical wave complex amplitude spatial distribution information of a second optical signal transmitted by a multi-plane optical transformation device; the first optical signal is an optical signal transmitted by an optical line terminal (OLT), and the second optical signal is an optical signal transmitted by an optical network unit (ONU);

[0041] A first processing module is configured to determine a phase template pattern of each phase template of a phase substrate in the multi-plane optical transformation device according to the optical wave complex amplitude spatial distribution information of the first optical signal and the optical wave complex amplitude spatial distribution information of the second optical signal.

[0042] To achieve the above object, an embodiment of the present application provides a single-fiber bidirectional transmission processing device, comprising a transceiver, a processor, a memory and a program or instruction stored in the memory and executable on the processor; according to instructions transmitted by the transceiver, the processor executes the program or instruction to realize the single-fiber bidirectional transmission processing method as described above.

[0043] To achieve the above object, an embodiment of the present application provides a readable storage medium, which stores a program or instruction, and the program or instruction is executed by a processor to realize steps in the single-fiber bidirectional transmission processing method as described above.

[0044] The above technical solution of the present application has the following advantages:

[0045] The method of the embodiment of the present application can determine the phase template pattern of each phase template of the phase substrate in the multi-plane optical conversion device for the OLT side optical signal (first optical signal) and the ONU side optical signal (second optical signal) transmitted by the multi-plane optical conversion device, so that the multi-plane optical conversion device can utilize the characteristics that the uplink and downlink signal wavelengths are different to realize different responses to different wavelengths, that is, mode multiplexing for the uplink signal - solving the additional power loss, and power distribution for the downlink signal - realizing the broadcast function, so that the additional power loss of the uplink signal can be reduced, and the single-fiber bidirectional transmission is supported. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The flowchart of the method of the embodiment of the present application is shown in Figure 1.

[0047] Figure 2 The structural diagram of the multi-plane optical conversion device in the embodiment of the present application is shown in Figure 2.

[0048] Figure 3 The application diagram of the multi-plane optical conversion device in the embodiment of the present application is shown in Figure 3.

[0049] Figure 4 The application diagram of the method in the embodiment of the present application is shown in Figure 4.

[0050] Figure 5 The structural diagram of the device in the embodiment of the present application is shown in Figure 5.

[0051] Figure 6 The structural diagram of the device in another embodiment of the present application is shown in Figure 6. DETAILED DESCRIPTION

[0052] To make the technical problems, technical solutions and advantages of the present application clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0053] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily mean the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner.

[0054] In various embodiments of the present application, it should be understood that the size of the serial number of the following processes does not mean the order of execution, and the execution order of the processes should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0055] In addition, the terms "system" and "network" are often used interchangeably in this document.

[0056] In the embodiments provided in the present application, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that the determination of B according to A does not mean that B is determined only according to A, but B can also be determined according to A and / or other information.

[0057] For the convenience of understanding, some contents related to the embodiments of the present application are described as follows:

[0058] Phase refers to the position of the electromagnetic wave corresponding to the input light field in the cycle at a specific moment when the electromagnetic wave is transmitted in the optical fiber. Multi-plane light conversion (MPLC) is a device that modulates (changes) the wave front (phase) of the incident light wave continuously multiple times by using a sequence of spatially equidistant phase masks, and finally obtains a light wave with a spatial distribution meeting the specified requirements at a specified output position. The basic principle of its operation is wave front modulation and diffraction effect of light in propagation, and the combination of the two is to transform the wave front (phase) modulation into amplitude modulation through diffraction, forming a light wave with a specific spatial (energy and phase) distribution. Designing phase masks with different patterns will obtain output light waves with different spatial distributions, therefore, only by specifying the spatial distribution of the input and output light waves, the pattern of each phase mask can be calculated according to a certain flow algorithm to realize different functions.

[0059] As shown in FIG. 1, a single-fiber bidirectional transmission processing method according to an embodiment of the present application includes the following steps. Figure 1

[0060] Step 101, obtaining the light wave complex amplitude spatial distribution information of a first optical signal and the light wave complex amplitude spatial distribution information of a second optical signal transmitted by a multi-plane light conversion device; wherein the first optical signal is an optical signal sent by an optical line terminal (OLT), and the second optical signal is an optical signal sent by an optical network unit (ONU).

[0061] Step 102, determining the phase mask pattern of each phase mask of a phase substrate in the multi-plane light conversion device according to the light wave complex amplitude spatial distribution information of the first optical signal and the light wave complex amplitude spatial distribution information of the second optical signal.

[0062] ​Therefore, the device applying the method of the embodiment of the present application can determine the phase template pattern of each phase template of the phase substrate in the multi-plane optical conversion device for the OLT-side optical signal (first optical signal) and the ONU-side optical signal (second optical signal) transmitted by the multi-plane optical conversion device, so that the multi-plane optical conversion device can realize different responses to different wavelengths by utilizing the feature that the uplink and downlink signal wavelengths are different, i.e., mode multiplexing for the uplink signal, solving the extra power loss, and power distribution for the downlink signal, realizing the broadcast function. Therefore, the extra power loss of the uplink signal can be reduced, the single-fiber bidirectional transmission is supported, the uplink power loss of the second optical signal is reduced without changing the existing passive optical network architecture, and the overall performance of the system is improved.

[0063] It should be noted that the device applying the method of the embodiment of the present application can be the multi-plane optical conversion device, or a device associated with the multi-plane optical conversion device. After the device determines the phase template pattern, the device can control each phase template of the phase substrate in the multi-plane optical conversion device to adjust to the corresponding pattern. Figure 2 As shown in the embodiment, the multi-plane optical conversion device comprises a first input / output end, a second input / output end, the phase substrate, and a plane mirror parallel to the phase substrate.

[0064] The first input / output end is connected to the OLT, and the second input / output end is connected to the ONU.

[0065] The phase template patterns are etched side by side on the phase substrate. Each phase template pattern corresponds to a phase template of the phase substrate. The phase template pattern refers to the ups and downs of different positions on the surface of the phase substrate. The ups and downs will introduce a spatial phase shift consistent with the height change of the substrate to the light wave incident on the phase substrate. The bottom of the phase substrate is plated with a metal film to realize high reflection of the light wave. Therefore, the light wave modulated by the phase template is reflected to the plane mirror, and the plane mirror reflects the light to the phase substrate again. When the light wave is obliquely incident at a certain angle in the horizontal direction (x direction), the light wave is reflected multiple times between the phase substrate and the plane mirror, and each time the light wave is reflected to the phase substrate, there is a lateral displacement to ensure that the light wave falls into different phase templates. This multiple reflection cavity structure has the advantages of simplicity, easy processing, and alignment. In addition, the phase change obtained by reflecting the light wave once through the phase template is twice the phase change caused by single transmission.

[0066] It should be noted that in this embodiment, the multi-plane light transforming device can achieve different responses to light waves of different wavelengths because 1) the phase template pattern causes different phase changes to light waves of different wavelengths. Because the phase change is proportional to the ratio of the height change to the wavelength, i.e., ΔΦ(x, y) ∝ Δd(x, y) / λ, where Δ represents the change relative to the reference, Φ represents the spatial phase of the light wave, d represents the surface height of the phase substrate, and they are functions of the spatial position (x, y), and λ represents the wavelength of the light wave. 2) the phase lag caused by the propagation of light waves of different wavelengths for the same distance is different. By using these two wavelength-sensitive factors, different responses to light waves of different wavelengths can be achieved. Because the uplink and downlink signal wavelengths are different in the TDM-PON system, the MPLC device can be used to achieve the functions of uplink mode multiplexing and downlink power distribution.

[0067] Therefore, the multi-plane light transforming device with the phase template pattern is applied to a passive optical network, the first input / output end is connected to an OLT, and the second input / output end is connected to an ONU, as shown in Figure 3 The second input / output end of the multi-plane light transforming device can be connected to multiple ONUs. Among them, the optical signals (uplink optical signals) sent by the g ONUs pass through the multi-plane light transforming device, and output optical signals t1, t2, t3, …, tg are obtained. g-1 g .

[0068] Optionally, as shown in Figure 2 The first input / output end and the second input / output end are also provided with lenses. The lenses can collimate and expand the light waves emitted by the optical fibers, so that the light spots falling on the phase substrate have a certain size to cover enough pixels (the smallest structural unit of the phase pattern).

[0069] In addition, when the multi-plane light transforming device is applied, the arrangement position of the input / output light spots needs to be determined so that 1) the arrangement matches the external input / output (such as an optical fiber array) well; and 2) the light spots as a whole have multiple symmetries, which can simplify the phase template pattern, reduce the number of required phase templates, and keep the performance of the device unchanged.

[0070] Optionally, in this embodiment, as shown in Figure 2 ​As shown, the second input-output end arranges the optical signals from different ONUs into a column, i.e. multiple optical spots on the ONU side are arranged into a column. Among them, the center-to-center distance of the optical spots can be set to a specific value (such as 250 microns) to match the commonly used strip fiber spacing requirements. Moreover, the middle part of the column of multiple optical spots corresponds to low-order modes, and the farther the optical spot is, the higher the mode order is. Taking the 6-mode-10 linear polarization mode (LP) as an example, the modes corresponding to the optical spots from the middle to both sides are LP01, LP11e, LP11o, LP21o, LP21e, LP02, LP31e, LP31o, LP12e, and LP12o. Among them, LPmn(e / o) represents the LP mode, m / 2 zero points in the circumferential direction and (n-1) zero points in the radial direction, e represents left-right mirror symmetry, and o represents left-right mirror antisymmetry.

[0071] Of course, this is only an example, and the optical signals from different ONUs at the second input-output end are not limited to this arrangement, and can include other multiple arrangements. The arrangement principle is that the optical signals corresponding to low-order modes are arranged inward, and the optical signals corresponding to high-order modes are arranged outward. The basic idea is that as the mode order increases, the transverse wave vector increases, and the divergence angle also increases, and more energy reaches the outside of the array, thereby ensuring a high quality of the multi-plane optical conversion device. The OLT side of the multi-plane optical conversion device is connected to a transmission optical fiber (few-mode / multi-mode) through a lens. The optical fiber supports low-loss transmission of multiple LP modes. Due to the complex mode structure of high-order modes, in order to generate high-quality LP modes with a limited pixel size of the phase mask, the generated LP mode needs to have a large size, such as a waist radius of hundreds of microns. The generated LP mode is coupled into the transmission optical fiber through a lens or a beam-reducing system with high efficiency. The centers of these LP modes are aligned and coincide with the center position of the optical spot array. For the downlink signal, since the wavelength is long, the transmission optical fiber mainly supports the fundamental mode, i.e. the LP01 mode. Therefore, the OLT side of the multi-plane optical conversion device is the fundamental mode amplified and collimated through the lens or the beam-expanding system (in the opposite direction, i.e. beam-reducing). The ONU side of the multi-plane optical conversion device is the fundamental mode optical spot completely coinciding with the uplink input, and the two only differ in wavelength.

[0072] In this embodiment, the optical wave complex amplitude spatial distribution information, i.e. the complex amplitude spatial distribution of the optical signal before the lens of the multi-plane optical conversion device, is shown.

[0073] In the embodiment of the application, the phase mask pattern is determined after the position, size, and spatial distribution information of the optical wave on both sides of the multi-plane optical conversion device are determined. In this embodiment, the complex amplitude distribution of the forward and backward propagating light reaching the front and back of the phase mask is calculated by using the beam propagation algorithm. The phase of the product of the two complex amplitude distributions characterizes their difference, and the phase is the pattern of the phase mask. Alternatively, step 102 includes:

[0074] setting each phase template of the phase substrate as a specific pattern;

[0075] In a case that the first light signal is input to the multi-plane light conversion device, the second light signal is input to the multi-plane light conversion device, and a third complex amplitude distribution corresponding to an n th phase template of the phase substrate is a specified complex amplitude distribution, a first complex amplitude distribution and a second complex amplitude distribution corresponding to the n th phase template are obtained according to light wave complex amplitude spatial distribution information of the first light signal and light wave complex amplitude spatial distribution information of the second light signal; wherein n is the number of phase templates of the phase substrate.

[0076] A phase template pattern of the n th phase template is determined according to the first complex amplitude distribution, the second complex amplitude distribution and the third complex amplitude distribution corresponding to the n th phase template.

[0077] First complex amplitude distribution, second complex amplitude distribution and third complex amplitude distribution corresponding to the remaining n-1 phase templates are sequentially obtained.

[0078] A phase template pattern of the remaining n-1 phase templates is determined according to the first complex amplitude distribution, the second complex amplitude distribution and the third complex amplitude distribution corresponding to the remaining n-1 phase templates.

[0079] The first complex amplitude distribution is a complex amplitude distribution before the first light signal propagates to the corresponding phase template; the second complex amplitude distribution is a complex amplitude distribution before the second light signal propagates to the corresponding phase template; and the third complex amplitude distribution is a complex amplitude distribution of an expected superposition of the first light signal and the second light signal propagating to the corresponding phase template.

[0080] The specific pattern is a uniform and flat phase pattern, and the specific patterns used by different phase templates can be the same or different. For the n th phase template, the first complex amplitude distribution is a complex amplitude distribution before the first light signal propagates to the phase template, and the second complex amplitude distribution is a complex amplitude distribution before the second light signal propagates to the phase template, which can be determined based on the phase template of the specific pattern and the light wave complex amplitude spatial distribution information of the first light signal and the light wave complex amplitude spatial distribution information of the second light signal. After the first complex amplitude distribution and the second complex amplitude distribution corresponding to the n th phase template are determined, the third complex amplitude distribution corresponding to the n th phase template can be further obtained. The third complex amplitude distribution is related to the first light signal and the second light signal, is a superposition of an output light complex amplitude distribution of the expected first light signal propagating to the last phase template and an output light complex amplitude distribution of the second light signal propagating to the last phase template, and satisfies a specified distribution requirement. The specified distribution requirement is predefined or configured.

[0081] Thus, the third complex amplitude distribution corresponding to the nth phase template can determine the phase template pattern of the nth phase template.

[0082] Next, after the phase template pattern of the nth phase template is determined, the first complex amplitude distribution, the second complex amplitude distribution and the third complex amplitude distribution corresponding to the remaining n-1 phase templates are further obtained in sequence. That is, similar to the nth phase template, the first complex amplitude distribution, the second complex amplitude distribution and the third complex amplitude distribution corresponding to the phase templates are obtained in sequence from the n-1th phase template to the 1st phase template. For the third complex amplitude distribution of the remaining n-1 phase templates, the phase template patterns of the remaining n-1 phase templates are determined.

[0083] Optionally, in the embodiment, the first complex amplitude distribution, the second complex amplitude distribution and the third complex amplitude distribution corresponding to the mth phase template in the remaining n-1 phase templates are determined after the phase template patterns of the m+1th phase template to the nth phase template are determined; wherein m is an integer greater than or equal to 1 and less than n.

[0084] That is, after the first optical signal and the second optical signal are input to the multi-plane optical transformation device (the phase template pattern of the nth phase template is determined), the input complex amplitude distribution of the first optical signal transmitted through the first phase template to the second last phase template (i.e. the first complex amplitude distribution corresponding to the n-1th phase template) and the input complex amplitude distribution of the second optical signal transmitted through the last phase template to the second last phase template (i.e. the second complex amplitude distribution corresponding to the n-1th phase template) are obtained, so as to obtain the third complex amplitude distribution corresponding to the n-1th phase template from the first complex amplitude distribution and the second complex amplitude distribution, and then determine the phase template pattern of the n-1th phase template.

[0085] For the phase template image of the n-2th phase template, the first optical signal and the second optical signal need to be input to the multi-plane optical transformation device (the phase template patterns of the nth phase template and the n-1th phase template are determined) again, and the input complex amplitude distribution of the first optical signal transmitted through the first phase template to the third last phase template (i.e. the first complex amplitude distribution corresponding to the n-2th phase template) and the input complex amplitude distribution of the second optical signal transmitted through the last phase template, the second last phase template to the third last phase template (i.e. the second complex amplitude distribution corresponding to the n-2th phase template) are obtained, so as to obtain the third complex amplitude distribution corresponding to the n-2th phase template from the first complex amplitude distribution and the second complex amplitude distribution, and then determine the phase template pattern of the n-2th phase template.

[0086] Similarly, by taking m=n-1, n-2, …, 1 respectively, the complex amplitude distribution of the light wave before and after each phase template is calculated one by one by an iterative method, and the determination of the phase template pattern of the remaining n-1 phase templates is completed.

[0087] It should be noted that when the phase template pattern of the mth phase template is determined, since the patterns of the phase templates before the mth phase template have not been determined, the first light signal can also not be input to the multi-plane optical transformation device again, and the complex amplitude distribution of the first light signal propagating to the phase template before the mth phase template, i.e., the first complex amplitude distribution corresponding to the mth phase template, can be directly used.

[0088] The method of the embodiment of the application can calculate the complex amplitude distribution of the light wave before and after each phase template one by one by an iterative method.

[0089] Optionally, in this embodiment, the third complex amplitude distribution corresponding to the nth phase template is obtained according to the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template, and the third complex amplitude distribution comprises:

[0090] The first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template are respectively subtracted from a target value and then accumulated to obtain the third complex amplitude distribution;

[0091] The target value is a linear polarization mode space electric field distribution inherent to the few-mode fiber.

[0092] Optionally, the phase template pattern of the nth phase template is determined according to the third complex amplitude distribution corresponding to the nth phase template, and the third complex amplitude distribution comprises:

[0093] The phase information of the third complex amplitude corresponding to the nth phase template is extracted to obtain the phase template pattern of the nth phase template.

[0094] Similarly, for the phase template patterns of the remaining n-1 phase templates, the third complex amplitude distribution can also be obtained by subtracting the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template from a target value and then accumulating the third complex amplitude distribution, and then the phase information of the third complex amplitude is extracted to obtain the phase template pattern of the phase template.

[0095] It should be understood that for a plurality of independent light beams with the same wavelength, the phase template pattern only needs to multiply and accumulate the complex amplitudes of the forward and backward propagation of each of the light beams and take the phase, and for a plurality of independent light beams with different wavelengths, the complex amplitudes of the light beams with different wavelengths can be converted to a specific wavelength and then accumulated. That is, the third complex amplitude distribution obtained by subtracting the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template from a target value and then accumulating the third complex amplitude distribution comprises:

[0096] In the case that the wavelength of the first optical signal and the second optical signal are different, the accumulation result is processed based on a specific wavelength.

[0097] Here, the processing of the accumulation result based on a specific wavelength includes that the complex amplitude product of different wavelength light is converted to the specific wavelength and then accumulated. For example, ΔΦ(x, y) = Σ i ΔΦ(x, y, λ i )λ i / λ ref , where λ i is the wavelength of the i-th optical signal, and λ ref is the specific wavelength. ΔΦ(x, y) represents the spatial phase distribution of the third complex amplitude, and ΔΦ(x, y, λ i ) represents the difference between the first or second complex amplitude distribution of wavelength i and the target distribution. The target distribution is the linear polarization mode space electric field distribution inherent to the few-mode fiber. Here, the complex amplitude of the backward propagating light needs to be conjugated, indicating time reversal.

[0098] In this embodiment, the specific wavelength is predetermined.

[0099] In addition, optionally, the embodiment further comprises:

[0100] After determining the phase template pattern of all phase templates for the p-th time, restarting the determination of the phase template pattern of the phase templates;

[0101] Wherein, p is less than a specific value; or the performance index corresponding to the phase template pattern determined for the p-th time does not meet the performance threshold.

[0102] That is, in the case that the determination of the phase template pattern of the n phase templates does not reach a certain number (specific value) or the performance does not meet the requirement (the performance index does not meet the performance threshold), the determination of the phase template pattern of the n phase templates for the p+1-th time needs to be restarted.

[0103] Wherein, the performance index corresponding to the phase template pattern can be the normalized result of the amplitude value of the overlap integral of the complex amplitude distribution of the optical wave propagating to the ONU side and the specified complex amplitude distribution. Here, the performance index is between 0 and 1, and the larger the better. Of course, in the case that the performance index improvement is less than a certain value after determining the phase template pattern of the n phase templates for two consecutive times, the determination of the new round can be stopped.

[0104] In addition, considering that the multi-plane optical transformation device is not balanced in the distribution of downlink signal power, the ONU located in the middle position has higher power, and the ONU located on both sides has lower power, in this embodiment, a pre-compensation technology is introduced, therefore, optionally, the method comprises:

[0105] obtaining a correction value of the target second optical signal, wherein the target second optical signal is a second optical signal with a power value greater than a first value;

[0106] correcting the optical power of the output optical signal of the multi-plane light transforming device inputted by the target second optical signal according to the correction value;

[0107] updating the optical wave complex amplitude spatial distribution information of the second optical signal and updating the phase mask pattern of all phase masks according to the corrected optical power.

[0108] That is, when calculating the phase pattern, the normalized power of the output end is appropriately reduced for the optical wave of the ONU with higher power. In this way, the optical wave complex amplitude spatial distribution information of the second optical signal can be updated according to the modified optical power, and then the phase mask pattern of all phase masks is updated by the new optical wave complex amplitude spatial distribution information of the second optical signal. The specific updating method is as described above for determining the phase mask pattern of the phase mask, and will not be described here.

[0109] Optionally, the obtaining of the correction value of the target second optical signal comprises:

[0110] dividing the power value of the target second optical signal by the average power value of the optical signals sent by all ONUs, subtracting 1, and multiplying by a control factor to obtain the correction value of the target second optical signal.

[0111] That is, the relative error is calculated based on the average power of the output optical wave at all ONU ports for the target second optical signal, and the normalized power of the output end is corrected by using the relative error to ensure that the final power of each ONU is equal. For example, the relative error of the target second optical signal (the optical signal sent by a certain ONU) is equal to the power value of the target second optical signal divided by the average power value of the optical signals sent by all ONUs, subtracting 1, and multiplying by a control factor. Here, the control factor is predetermined and can be 0.1-0.3.

[0112] Optionally, the correcting the optical power of the output optical signal of the multi-plane light transforming device inputted by the target second optical signal according to the correction value comprises:

[0113] normalizing the optical power of the output optical signal to obtain a normalized power;

[0114] calculating a corrected optical power of the output optical signal according to the normalized power, the correction value, and a control factor.

[0115] Here, the control factor is predetermined and can be 0.1-0.3. The modified power of the output optical signal is equal to the normalized power multiplied by (1 minus the modification value multiplied by the control factor). When the modification value is positive, the modified power of the output optical signal decreases, and vice versa. The adjustment process is accompanied by determination of the phase pattern each time. After modification, the multi-plane optical transformation device can achieve more uniform power distribution.

[0116] Optionally, in this embodiment, the specific pattern is a non-fixed pattern. That is, the specific pattern is adapted according to performance, scene, and other factors.

[0117] It should be noted that, in this embodiment, the forward propagation is the transmission direction of the second optical signal; the backward propagation is the transmission direction of the first optical signal.

[0118] Next, the specific application of the method of the embodiment of the application in a controller will be described. Figure 4

[0119] The controller initializes the multi-plane optical transformation device and sets each phase template thereof to a specific pattern, such as no pattern.

[0120] The controller controls the backward propagation field to each phase template, that is, the first optical signal is input to the multi-plane optical transformation device and propagates to each phase template; and controls the forward propagation field to the cth phase template, that is, the second optical signal is input to the multi-plane optical transformation device and propagates to the cth phase template. In this way, before the phase template pattern of the cth phase template is determined, the first complex amplitude distribution, the second complex amplitude distribution, and the third complex amplitude distribution corresponding to the cth phase template are obtained. c is an integer greater than or equal to 1 and less than or equal to n.

[0121] The controller determines the phase template pattern of the cth phase template; wherein the phase template pattern of each phase template is determined in reverse order from the nth phase template. The phase template pattern of the cth phase template can be represented as:

[0122] wherein c = 1, …, n.E f,s (x, y, cL; λ) represents the forward propagation field before propagating to the cth phase template, represents the backward propagation field before propagating to the cth phase template. f represents a template before (foward), and s represents the optical field complex amplitude of the st ONU.

[0123] ​The controller determines whether to restart determining the phase pattern of the n phase templates based on a comparison between p and a specific value, or whether the performance index corresponding to the phase pattern of the n phase templates determined for the pth time meets a performance threshold. In the case that p is less than the specific value, or the performance index corresponding to the phase pattern of the n phase templates determined for the pth time does not meet the performance threshold, the controller controls the backward propagation field to each phase template; otherwise, the process ends.

[0124] In summary, in the embodiment of the present application, the phase pattern of the multi-plane light transformation device is determined, so that the multi-plane light transformation device can be used to simultaneously realize upstream multiplexing and downstream functions, thereby supporting single-fiber bidirectional transmission. The multi-plane light transformation device has both mode selectivity and wavelength sensitivity: the mode selectivity is different responses to different spatial modes (including position and distribution), which is the basis for realizing upstream multiplexing; and the wavelength sensitivity is different responses to the same spatial mode with different wavelengths, which is a necessary condition for separately realizing upstream multiplexing and downstream power splitting.

[0125] As shown in Figure 5 A single-fiber bidirectional transmission processing device according to an embodiment of the present application includes:

[0126] The first acquisition module 510 is configured to acquire light wave complex amplitude spatial distribution information of a first optical signal transmitted by a multi-plane light transformation device and light wave complex amplitude spatial distribution information of a second optical signal; wherein the first optical signal is an optical signal transmitted by an optical line terminal (OLT), and the second optical signal is an optical signal transmitted by an optical network unit (ONU).

[0127] The first processing module 520 is configured to determine a phase pattern of each phase template of a phase substrate in the multi-plane light transformation device according to the light wave complex amplitude spatial distribution information of the first optical signal and the light wave complex amplitude spatial distribution information of the second optical signal.

[0128] Optionally, the first processing module includes:

[0129] The first processing unit is configured to set each phase template of the phase substrate to a specific pattern.

[0130] The second processing unit is configured to acquire a first complex amplitude distribution and a second complex amplitude distribution corresponding to the nth phase template according to the light wave complex amplitude spatial distribution information of the first optical signal and the light wave complex amplitude spatial distribution information of the second optical signal; wherein n is the number of phase templates of the phase substrate.

[0131] a third processing unit, configured to obtain a third complex amplitude distribution corresponding to the nth phase pattern according to the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase pattern;

[0132] a fourth processing unit, configured to determine the phase pattern of the nth phase pattern according to the third complex amplitude distribution corresponding to the nth phase pattern;

[0133] a fifth processing unit, configured to sequentially obtain the first complex amplitude distribution, the second complex amplitude distribution and the third complex amplitude distribution corresponding to the remaining n-1 phase patterns;

[0134] a sixth processing unit, configured to determine the phase pattern of the remaining n-1 phase patterns according to the third complex amplitude distribution corresponding to the remaining n-1 phase patterns;

[0135] The first complex amplitude distribution is a complex amplitude distribution before the first optical signal propagates to the corresponding phase pattern; the second complex amplitude distribution is a complex amplitude distribution before the second optical signal propagates to the corresponding phase pattern; and the third complex amplitude distribution is an expected superimposed complex amplitude distribution of the first optical signal and the second optical signal propagating to the corresponding phase pattern.

[0136] Optionally, the first complex amplitude distribution, the second complex amplitude distribution and the third complex amplitude distribution corresponding to an mth phase pattern in the remaining n-1 phase patterns are determined in a case where the phase pattern of an m+1th phase pattern to an nth phase pattern has been determined; wherein m is an integer greater than or equal to 1 and less than n.

[0137] Optionally, the third processing unit is further configured to:

[0138] obtain the third complex amplitude distribution by subtracting and accumulating the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase pattern from a target value respectively;

[0139] The target value is a linear polarization mode space electric field distribution inherent to the few-mode fiber.

[0140] Optionally, the fourth processing unit is further configured to:

[0141] obtain the phase pattern of the nth phase pattern by extracting phase information of the third complex amplitude corresponding to the nth phase pattern.

[0142] Optionally, the third processing unit is further configured to:

[0143] In a case where the wavelength of the first optical signal and the wavelength of the second optical signal are different, processing the accumulation result based on a specific wavelength.

[0144] Optionally, the apparatus further comprises:

[0145] a restarting module configured to restart the determination of the phase mask pattern of the phase mask after the pth determination of the phase mask pattern of all phase masks;

[0146] wherein p is less than a specific value; or the performance index corresponding to the pth determined phase mask pattern does not satisfy a performance threshold.

[0147] Optionally, the apparatus further comprises:

[0148] a seventh processing module configured to obtain a correction value of a target second optical signal; wherein the target second optical signal is a second optical signal with a power value greater than a first value;

[0149] an eighth processing module configured to correct the optical power of an output optical signal of the multi-plane optical transformation device according to the correction value;

[0150] a ninth processing module configured to update the optical wave complex amplitude spatial distribution information of the second optical signal and update the phase mask pattern of all phase masks according to the corrected optical power.

[0151] Optionally, the seventh processing module is further configured to:

[0152] divide the power value of the target second optical signal by the average power value of the optical signals sent by all ONUs, subtract 1, and multiply by a control factor to obtain the correction value of the target second optical signal.

[0153] Optionally, the eighth processing module is further configured to:

[0154] normalize the optical power of the output optical signal to obtain a normalized power;

[0155] calculate a corrected optical power of the output optical signal according to the normalized power, the correction value, and a control factor.

[0156] Optionally, the multi-plane optical transformation device comprises: a first input / output end; a second input / output end; the phase substrate; and a plane mirror parallel to the phase substrate;

[0157] wherein the first input / output end is connected to an OLT; and the second input / output end is connected to an ONU.

[0158] Optionally, the specific pattern is a non-fixed pattern.

[0159] The device of the embodiment can determine the phase template pattern of each phase template of the phase substrate in the multi-plane optical conversion device for the OLT side optical signal (first optical signal) and the ONU side optical signal (second optical signal) transmitted by the multi-plane optical conversion device, so that the multi-plane optical conversion device can utilize the characteristics that the uplink and downlink signal wavelengths are different to realize different responses to different wavelengths, that is, mode multiplexing for the uplink signal - solving the additional power loss, and power distribution for the downlink signal - realizing the broadcast function, so that the additional power loss of the uplink signal can be reduced, and the single-fiber bidirectional transmission is supported.

[0160] It should be noted that the device is a device applied to the above method, and the implementation manner of the method embodiment is applicable to the device, and the same technical effects can also be achieved.

[0161] Another embodiment of the application is a single-fiber bidirectional transmission processing device, as shown in Figure 6 The device includes a transceiver 610, a processor 600, a memory 620, and a program or instruction stored in the memory 620 and executable on the processor 600; and the processor 600 implements the single-fiber bidirectional transmission processing method described above when executing the program or instruction.

[0162] The transceiver 610 is configured to receive and send data under the control of the processor 600.

[0163] In the above Figure 6 The bus architecture can include any number of interconnected buses and bridges, which are specifically linked together by various circuits of one or more processors represented by the processor 600 and the memory represented by the memory 620. The bus architecture can also link various other circuits such as peripheral devices, voltage stabilizers, and power management circuits, which are well known in the art, and thus, further description thereof will not be given herein. The bus interface provides an interface. The transceiver 610 can be a plurality of elements, that is, it includes a transmitter and a receiver, and provides a unit for communicating with various other devices on a transmission medium.

[0164] The processor 600 is responsible for managing the bus architecture and general processing, and the memory 620 can store data used by the processor 600 when performing operations.

[0165] The readable storage medium of the embodiment of the application has a program or instruction stored thereon, and the program or instruction is executed by the processor to implement the steps in the single-fiber bidirectional transmission processing method described above and achieve the same technical effects. To avoid repetition, further description will not be given herein.

[0166] The processor is the processor in the external network access controller in the above embodiments. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0167] It is further noted that many of the functional components described in this specification are referred to as modules to more particularly emphasize their independence from other functional components.

[0168] In the embodiments of the present application, the modules can be implemented in software, to be executed by various types of processors. For example, an identified executable code module can include one or more physical or logical blocks of computer instructions. For example, it can be structured as an object, a procedure, or a function. However, the executable code of an identified module need not be physically located together, but can include different instructions stored in different locations which, when joined logically together, comprise the module and achieve the stated purpose for the module.

[0169] In fact, an executable code module can be a single instruction, or many instructions, and can even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data can be identified within the modules, and can be

[0170] When the modules can be implemented in software, in view of the level of existing hardware technology, the modules implemented in software can be built into corresponding hardware circuits by those skilled in the art without considering the cost, and the hardware circuits include conventional very large scale integration (VLSI) circuits or gate arrays, and existing semiconductors such as logic chips, transistors, and other discrete elements. The modules can also be implemented in programmable hardware devices, such as field programmable gate arrays, programmable array logic, programmable logic devices, etc.

[0171] The foregoing exemplary embodiments are described with reference made to the drawings which are provided for the purpose of explanation and illustration. They are not intended to limit the scope of the invention. Rather, these exemplary embodiments are described in order to enable others skilled in the art to embody the application. As will be understood by those familiar with the art, the application can be embodied in many different forms and should not be limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be complete and fully convey the scope of the application to those skilled in the art. In the drawings, the size and relative sizes of components can be exaggerated for clarity. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular articles "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Unless otherwise indicated, a value range includes the upper and lower limits of the range and any sub-ranges therebetween.

[0172] The above description is that of the preferred embodiments of the application. Various modifications and changes can be made thereto without departing from the spirit and scope of the application, which is to be understood. The scope of the application is indicated only by the subjoined claims.

Claims

1. A single-fiber bidirectional transmission processing method, characterized in that, include: The spatial distribution information of the complex amplitude of the first optical signal and the spatial distribution information of the complex amplitude of the second optical signal transmitted by the multi-plane optical converter are obtained; wherein, the first optical signal is the optical signal sent by the optical line terminal (OLT) and the second optical signal is the optical signal sent by the optical network unit (ONU); Based on the spatial distribution information of the complex amplitude of the first optical signal and the spatial distribution information of the complex amplitude of the second optical signal, the phase template pattern of each phase template of the phase substrate in the multi-plane optical conversion device is determined. The step of determining the pattern of each phase template on the phase substrate in the multi-plane optical conversion device based on the spatial distribution information of the complex amplitude of the first optical signal and the spatial distribution information of the complex amplitude of the second optical signal includes: Each phase template of the phase substrate is set to a specific pattern; Based on the spatial distribution information of the complex amplitude of the first optical signal and the spatial distribution information of the complex amplitude of the second optical signal, the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template are obtained; where n is the number of phase templates of the phase substrate; Based on the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template, the third complex amplitude distribution corresponding to the nth phase template is obtained; The phase template pattern of the nth phase template is determined based on the third complex amplitude distribution corresponding to the nth phase template. Sequentially obtain the first complex amplitude distribution, the second complex amplitude distribution, and the third complex amplitude distribution corresponding to the remaining n-1 phase templates; Based on the third complex amplitude distribution corresponding to the remaining n-1 phase templates, determine the phase template pattern of the remaining n-1 phase templates; Wherein, the first complex amplitude distribution is the complex amplitude distribution of the first optical signal before it propagates to the corresponding phase template; the second complex amplitude distribution is the complex amplitude distribution of the second optical signal before it propagates to the corresponding phase template; and the third complex amplitude distribution is the expected superposition of the complex amplitude distributions of the first optical signal and the second optical signal as they propagate to the corresponding phase template. The step of obtaining the third complex amplitude distribution corresponding to the nth phase template based on the first and second complex amplitude distributions corresponding to the nth phase template includes: The third complex amplitude distribution is obtained by subtracting the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template from the target value and then summing them. The target value is the spatial electric field distribution of the linear polarization mode inherent in the few-mode fiber.

2. The method according to claim 1, characterized in that, Among the remaining n-1 phase templates, the first complex amplitude distribution, the second complex amplitude distribution, and the third complex amplitude distribution corresponding to the m-th phase template are determined when the phase template patterns of the (m+1)-th to n-th phase templates have been determined; where m is an integer greater than or equal to 1 and less than n.

3. The method according to claim 1, characterized in that, The step of determining the phase template pattern of the nth phase template based on the third complex amplitude distribution corresponding to the nth phase template includes: The phase template pattern of the nth phase template is obtained by extracting the phase information of the third complex amplitude corresponding to the nth phase template.

4. The method according to claim 1, characterized in that, The step of subtracting the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template from the target value and then summing them to obtain the third complex amplitude distribution includes: When the wavelengths of the first optical signal and the second optical signal are different, the accumulation result is processed based on a specific wavelength.

5. The method according to claim 1, characterized in that, Also includes: After determining the phase template pattern of all phase templates for the pth time, restart the determination of the phase template pattern of the phase template. Where p is less than a specific value; Alternatively, the performance index corresponding to the phase template pattern determined in the p-th iteration does not meet the performance threshold.

6. The method according to claim 1, characterized in that, Also includes: Obtain the correction value of the target second optical signal; wherein, the target second optical signal is a second optical signal with a power value greater than the first value; Based on the correction value, the optical power of the optical signal output after the target second optical signal is input into the multi-plane optical converter is corrected; Based on the corrected optical power, update the spatial distribution information of the complex amplitude of the second optical signal, and update the phase template pattern of all phase templates.

7. The method according to claim 6, characterized in that, The process of obtaining the correction value of the target's second optical signal includes: The correction value of the target second optical signal is obtained by dividing the power value of the target second optical signal by the average power value of all optical signals transmitted by the ONU, subtracting 1, and then multiplying by a control factor.

8. The method according to claim 6 or 7, characterized in that, The step of correcting the optical power of the optical signal output from the multi-plane optical converter after the target second optical signal is input into the multi-plane optical converter according to the correction value includes: The optical power of the output optical signal is normalized to obtain the normalized power; The corrected power of the output optical signal is calculated based on the normalized power, the correction value, and the control factor.

9. The method according to claim 1, characterized in that, The multi-plane optical conversion device includes: a first input / output terminal; a second input / output terminal; the phase substrate; and a plane mirror parallel to the phase substrate. The first input / output terminal is connected to the OLT; the second input / output terminal is connected to the ONU.

10. The method according to claim 1, characterized in that, The specific pattern is a non-fixed pattern.

11. A single-fiber bidirectional transmission processing device, characterized in that, include: The first acquisition module is used to acquire the spatial distribution information of the optical wave complex amplitude of the first optical signal and the spatial distribution information of the optical wave complex amplitude of the second optical signal transmitted by the multi-plane optical conversion device; wherein, the first optical signal is the optical signal sent by the optical line terminal OLT and the second optical signal is the optical signal sent by the optical network unit ONU. The first processing module is used to determine the phase template pattern of each phase template of the phase substrate in the multi-plane optical conversion device based on the spatial distribution information of the optical wave complex amplitude of the first optical signal and the spatial distribution information of the optical wave complex amplitude of the second optical signal. The first processing module includes: The first processing unit is used to set each phase template of the phase substrate into a specific pattern; The second processing unit is used to obtain the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template based on the spatial distribution information of the complex amplitude of the first optical signal and the spatial distribution information of the complex amplitude of the second optical signal; wherein n is the number of phase templates of the phase substrate; The third processing unit is used to obtain the third complex amplitude distribution corresponding to the nth phase template based on the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template. The fourth processing unit is used to determine the phase template pattern of the nth phase template based on the third complex amplitude distribution corresponding to the nth phase template. The fifth processing unit is used to sequentially acquire the first complex amplitude distribution, the second complex amplitude distribution, and the third complex amplitude distribution corresponding to the remaining n-1 phase templates; The sixth processing unit is used to determine the phase template pattern of the remaining n-1 phase templates based on the third complex amplitude distribution corresponding to the remaining n-1 phase templates; Wherein, the first complex amplitude distribution is the complex amplitude distribution of the first optical signal before it propagates to the corresponding phase template; the second complex amplitude distribution is the complex amplitude distribution of the second optical signal before it propagates to the corresponding phase template; and the third complex amplitude distribution is the expected superposition of the complex amplitude distributions of the first optical signal and the second optical signal as they propagate to the corresponding phase template. The third processing unit is also used for: The third complex amplitude distribution is obtained by subtracting the first complex amplitude distribution and the second complex amplitude distribution corresponding to the nth phase template from the target value and then summing them. The target value is the spatial electric field distribution of the linear polarization mode inherent in the few-mode fiber.

12. A single-fiber bidirectional transmission processing device, comprising: A transceiver, a processor, a memory, and a program or instructions stored in the memory and executable on the processor; characterized in that, when the processor executes the program or instructions according to the instructions transmitted by the transceiver, it implements the single-fiber bidirectional transmission processing method as described in any one of claims 1-10.

13. A readable storage medium having a program or instructions stored thereon, characterized in that, When the program or instructions are executed by the processor, they implement the steps in the single-fiber bidirectional transmission processing method as described in any one of claims 1-10.

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