A fiber amplifier and method of amplifying an optical signal

Abstract

The application provides an optical fiber amplifier and a method for amplifying an optical signal. The optical fiber amplifier comprises: a first core pitch converter, configured to convert a first optical signal transmitted by a first N-core optical fiber into a second optical signal transmitted by a second N-core optical fiber; a gain module, configured to amplify the second optical signal according to a first pump light to obtain a third optical signal output by the gain module; and a second core pitch converter, configured to convert the third optical signal into a fourth optical signal transmitted by a third N-core optical fiber, wherein the core pitch of the first N-core optical fiber is the same as that of the third N-core optical fiber, the core pitch of the first N-core optical fiber is different from that of the second N-core optical fiber, and N is an integer greater than 1. The optical fiber amplifier provided by the application can reduce the damage of differential mode gain or mode-dependent gain to transmission performance by arranging a pair of core pitch converters.

Description

Technical Field

[0001] This application relates to the field of optical transmission technology, and in particular to an optical fiber amplifier and a method for amplifying optical signals. Background Technology

[0002] With the continuous development of optical fiber communication technology, multi-core fiber (MCF) has received widespread attention and research due to its ability to transmit space division multiplexing (SDM) optical signals. Based on the spacing between the fiber cores, MCF can be classified into three types: weakly coupled MCF, randomly coupled MCF, and supermode MCF. Among them, randomly coupled MCF has a core spacing between weakly coupled MCF and supermode MCF, resulting in a higher spatial channel density. However, there is coupling crosstalk between spatial modes, causing the spatial mode dispersion accumulation to be proportional to the root mean square of the transmission distance. Therefore, its spatial mode dispersion is significantly lower than that of supermode MCF, reducing the demodulation complexity of input-output (IMO) techniques at the receiver. MCF is considered the most competitive multi-core fiber and has attracted considerable attention.

[0003] However, for MCF amplifiers, amplifying signal light by tens to hundreds of times through doped fiber lengths of several meters to tens of meters requires optimizing the amplification performance of each fiber core while considering cost and system integration. This necessitates providing a higher core-cladding refractive index difference and numerical aperture, and appropriately reducing the mode field diameter. This weakens inter-mode coupling within the doped fiber, leading to an imbalance in gain between modes. Consequently, differential mode gain performance is difficult to suppress effectively, significantly impacting the long-distance transmission performance and capacity of randomly coupled multi-core fiber amplifiers. Therefore, reducing the differential mode gain of randomly coupled multi-core fiber amplifiers is a pressing issue that needs to be addressed. Summary of the Invention

[0004] This application provides an optical fiber amplifier and a method for amplifying optical signals for use in the field of optical fiber communication, which can reduce the damage to transmission performance caused by differential mode gain or mode-dependent gain.

[0005] In a first aspect, an optical fiber amplifier is provided, comprising: a first inter-core pitch converter for receiving a first optical signal transmitted from a first N-core optical fiber and converting the first optical signal into a second optical signal transmitted from a second N-core optical fiber; a gain module for amplifying the second optical signal according to a first pump light to obtain a third optical signal; and a second inter-core pitch converter for converting the third optical signal into a fourth optical signal transmitted from a third N-core optical fiber, wherein the first N-core optical fiber and the third N-core optical fiber have the same inter-core pitch, and the first N-core optical fiber and the second N-core optical fiber have different inter-core pitches, and N is an integer greater than 1.

[0006] Based on the above scheme, this application arranges a pair of core-pitch converters at the input and output of the fiber optic amplifier, which is suitable for signal amplification in coupled multi-core fiber optic transmission systems and helps to reduce differential mode gain or mode-dependent gain, thereby improving transmission performance.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, the gain module includes: a first module for coupling the second optical signal with the first pump light to obtain a first coupled optical signal; and an N-core gain fiber for amplifying the second optical signal in the first coupled optical signal to obtain a third optical signal output by the N-core gain fiber, wherein the second N-core fiber and the N-core gain fiber have the same core spacing.

[0008] In conjunction with the first aspect, in some implementations of the first aspect, the inter-core spacing of the first N-core optical fiber is smaller than the inter-core spacing of the second N-core optical fiber.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the inter-core spacing of the first N-core optical fiber ranges from 17 to 25 μm, and the inter-core spacing of the second N-core optical fiber is greater than 40 μm.

[0010] The first N-core optical fiber may include a randomly coupled N-core optical fiber, and the second N-core optical fiber may include a weakly coupled N-core optical fiber.

[0011] Based on the above scheme, the core spacing of randomly coupled transmission fibers is converted into weakly coupled core spacing by a core spacing converter, thus forming a weakly coupled multi-core fiber amplifier and realizing the weakly coupled multi-core amplification effect.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the inter-core spacing of the first N-core optical fiber is greater than the inter-core spacing of the second N-core optical fiber.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the inter-core spacing of the first N-core optical fiber ranges from 17 to 25 μm, and the inter-core spacing of the second N-core optical fiber ranges from 8 to 16 μm.

[0014] The first N-core optical fiber may include randomly coupled N-core optical fibers, and the second N-core optical fiber may include randomly coupled N-core optical fibers, but the core spacing of the second N-core optical fiber is smaller than that of the first N-core optical fiber.

[0015] Based on the above scheme, the core spacing of the randomly coupled transmission fiber is converted into the core spacing required for repeated random coupling by the core spacing converter. The small core spacing enables the signal to generate random energy coupling at the same time during the amplification process, which helps to reduce differential mode dispersion, thereby helping to reduce differential mode gain or mode-dependent gain and improve transmission performance.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the first module includes: a first laser group comprising N pump lasers for generating N paths of second pump light; a first pump light fan-in for coupling the N paths of second pump light into a fourth N-core optical fiber to generate first pump light; and a first combiner for coupling the second optical signal with the first pump light to generate the first coupled optical signal.

[0017] It should be noted that the core spacing of the fourth N-core fiber can be the same as that of the second N-core fiber. Alternatively, the core spacing of the fourth N-core fiber can be different from that of the second N-core fiber. When the core spacings of the two N-core fibers are different, a special multiplexer can be used to couple the second optical signal in the second N-core fiber to the first coupled pump light in the fourth N-core fiber, thus coupling the optical signal in each core of the second N-core fiber to the pump light in each core of the fourth N-core fiber one by one. Furthermore, this N-core gain fiber can be an N-core doped fiber or other types of fiber.

[0018] Based on the above scheme, the core pump is adjusted by using a pumped optical fan-inductor, which is beneficial for individually controlling the amplification performance of each fiber core and for controlling the consistency of amplification performance between cores. Furthermore, the optical layers of the signal paths in each core of the fiber amplifier in this application are consistent, preventing the accumulation of delay differences. This resolves many limitations imposed by delay difference accumulation, such as increased complexity in received signal processing, power consumption, switching delay, and maintenance, significantly improving practicality.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, the first module includes: a first laser for generating a first pump light; and a second combiner for coupling the second optical signal with the first pump light to generate the first coupled optical signal, wherein the N-core gain fiber includes a double-clad N-core gain fiber.

[0020] Based on the above scheme, multiple fiber cores can share a single pump light, simplifying the pump structure of the device.

[0021] In conjunction with the first aspect, in some implementations of the first aspect, the fiber amplifier further includes: a first N-core optical isolator for isolating reflected light from the output of the first N-core optical isolator, the first multi-core optical isolator being disposed between the N-core gain fiber and the first core pitch converter.

[0022] In conjunction with the first aspect, in some implementations of the first aspect, the fiber amplifier further includes: a second N-core optical isolator for isolating reverse noise generated by the N-core gain fiber, the second N-core optical isolator being disposed between the first core pitch converter and the first module.

[0023] Based on the above scheme, by setting isolators at the input and output ends of the amplifying fiber, it is possible to isolate the leakage of reverse ASE noise light generated by the amplifying fiber from the input end, and at the same time isolate the reflected light from other components at the output end. This can reduce and avoid the impact of reflected light entering the amplifying fiber on key performance indicators such as amplifier gain and noise figure.

[0024] In conjunction with the first aspect, in some implementations of the first aspect, the fiber amplifier further includes:

[0025] A gain flattening filter is used to equalize the gain of the third optical signal. The gain flattening filter is placed between the N-core gain fiber and the second core pitch converter.

[0026] Based on the above scheme, by deploying a gain flattening filter between the second optical isolator and the second interpitch converter, the amplifier gain medium can achieve wavelength-dependent gain equalization of the signal to be basically consistent.

[0027] In conjunction with the first aspect, in some implementations of the first aspect, the fiber amplifier further includes: a second module for acquiring N channels of third pump light.

[0028] In conjunction with the first aspect, in some implementations of the first aspect, the second module includes: a second laser group comprising N pump lasers for generating the N paths of third pump light; a second pump light fan-in for coupling the N paths of third pump light into a fifth N-core fiber to generate a fourth pump light; and a wavelength division multiplexer for coupling the fourth pump light into the N-core gain fiber, wherein the core spacing of the fifth N-core fiber may be the same as or different from the core spacing of the N-core gain fiber.

[0029] Based on the above scheme, a set of pump lasers is added to the gain fiber output end of the fiber amplifier to form a bidirectional pumping structure, which can balance the noise figure and improve the power conversion efficiency.

[0030] Secondly, a method for amplifying an optical signal is provided. The method includes: converting a first optical signal transmitted through a first N-core optical fiber into a second optical signal transmitted through a second N-core optical fiber; amplifying the second optical signal using a first pump light to obtain a third optical signal output by a gain module; and converting the third optical signal into a fourth optical signal transmitted through a third N-core optical fiber, wherein the first N-core optical fiber and the third N-core optical fiber have the same core spacing, and the first N-core optical fiber and the second N-core optical fiber have different core spacings, and N is an integer greater than 1.

[0031] It should be understood that the method also includes receiving a first optical signal transmitted from the first N-core optical fiber.

[0032] Based on the above scheme, a low differential mode gain amplification that supports random coupling transmission line applications is achieved by using a pair of core-to-core pitch converters, effectively solving the problem of damage to transmission performance caused by differential mode gain or mode-dependent gain.

[0033] In conjunction with the second aspect, in some implementations of the second aspect, the second optical signal is amplified by the first pump light to obtain the third optical signal output by the gain module, including: coupling the second optical signal with the first pump light to obtain a first coupled optical signal; amplifying the second optical signal in the first coupled optical signal to obtain the third optical signal output by the N-core gain fiber, wherein the second N-core fiber and the N-core gain fiber have the same core spacing.

[0034] In conjunction with the second aspect, in some implementations of the second aspect, the inter-core spacing of the first N-core optical fiber is smaller than the inter-core spacing of the second N-core optical fiber.

[0035] In conjunction with the second aspect, in some implementations of the second aspect, the inter-core spacing of the first N-core optical fiber ranges from 17 to 25 μm, and the inter-core spacing of the second N-core optical fiber is greater than 40 μm.

[0036] Optionally, the first N-core optical fiber includes a randomly coupled N-core optical fiber, and the second N-core optical fiber includes a weakly coupled N-core optical fiber.

[0037] Based on the above scheme, by converting the core spacing of randomly coupled transmission fibers to weakly coupled core spacing, the amplification effect of weakly coupled multi-core is achieved, thereby effectively solving the damage to transmission performance caused by differential mode gain or mode-dependent gain.

[0038] In conjunction with the second aspect, in some implementations of the second aspect, the inter-core spacing of the first N-core optical fiber is greater than the inter-core spacing of the second N-core optical fiber.

[0039] In conjunction with the second aspect, in some implementations of the second aspect, the inter-core spacing of the first N-core optical fiber ranges from 17 to 25 μm, and the inter-core spacing of the second N-core optical fiber ranges from 8 to 16 μm.

[0040] Optionally, in conjunction with the second aspect, in some implementations of the second aspect, the first N-core optical fiber includes a randomly coupled N-core optical fiber, and the second N-core optical fiber may also be a randomly coupled N-core optical fiber, but the core spacing of the second N-core optical fiber is smaller than the core spacing of the first N-core optical fiber.

[0041] Based on the above scheme, by converting the core spacing of the randomly coupled transmission fiber to the core spacing of the gain fiber to meet the requirements of repetitive random coupling, a smaller core spacing allows the signal to be fully coupled simultaneously rather than isolated during amplification, while also supporting amplification of more fiber cores. This scheme helps reduce differential mode dispersion, thereby helping to reduce differential mode gain or mode-dependent gain, and improving transmission performance.

[0042] In conjunction with the second aspect, in some implementations of the second aspect, coupling the second optical signal with the first pump light to obtain the first coupled optical signal includes: generating N channels of second pump light; coupling the N channels of second pump light into a fourth N-core optical fiber to generate the first pump light; and coupling the second optical signal with the first pump light to generate the first coupled optical signal.

[0043] The core spacing of the fourth N-core fiber can be the same as or different from that of the second N-core fiber. Different multiplexers are used to couple the signals in each core of the second N-core fiber to the signals in each core of the fourth N-core fiber. Furthermore, the N-core gain fiber can be an N-core doped fiber, such as erbium-doped fiber, or other types of fiber, such as nonlinear optical fiber.

[0044] Based on the above scheme, the use of a core pump method is beneficial for individually adjusting the amplification performance of each core, for controlling the consistency of amplification performance between cores, and for ensuring that the optical layers of the signal paths of each core are consistent, thus avoiding the problem of time delay difference accumulation. This resolves the limitations of receiving signal processing complexity and power consumption caused by the need to solve the problem of time delay difference accumulation.

[0045] In conjunction with the second aspect, in some implementations of the second aspect, coupling the second optical signal with the first pump light to obtain the first coupled optical signal includes: generating the first pump light; coupling the second optical signal with the first pump light to generate the first coupled optical signal, wherein the N-core gain fiber includes a double-clad N-core gain fiber.

[0046] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: isolating the reflected light from the output of the first N-core optical isolator.

[0047] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes isolating the reverse noise generated by the N-core gain fiber.

[0048] Based on the above scheme, the system's performance and amplification effect are improved by using the reverse light from the input end of the isolation gain fiber and the reflected light from other components at the output end of the isolation gain fiber.

[0049] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: equalizing the gain of the third optical signal.

[0050] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: acquiring N third pump beams.

[0051] In conjunction with the second aspect, in some implementations of the second aspect, the method further includes: generating the N-channel third pump light, coupling the N-channel third pump light to a fifth N-core fiber to generate a fourth pump light, wherein the core spacing of the fifth N-core fiber can be the same as or different from the core spacing of the N-core gain fiber; and coupling the fourth pump light to the N-core gain fiber.

[0052] Based on the above scheme, the system's noise figure and power conversion efficiency can be balanced through a bidirectional pumping structure.

[0053] Thirdly, an optical fiber communication system is provided, comprising: an optical amplifier site, the optical amplifier site including the optical fiber amplifier as provided in the first aspect.

[0054] Fourthly, an apparatus for amplifying optical signals is provided, which is used to perform the method of the second aspect described above. Specifically, the apparatus may include units and / or modules for performing the method provided in the second aspect, such as a processing module and / or a transceiver module.

[0055] In one implementation, the device is an amplifier. When the device is an amplifier, the transceiver module can be a transceiver, or an input / output interface; the processing module can be a processor.

[0056] In another implementation, the device is a chip, chip system, or circuit for amplifying optical signals. When the device is a chip, chip system, or circuit in an optical signal amplification device, the transceiver module unit can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; the processing module can be a processor, processing circuit, or logic circuit.

[0057] Based on the beneficial effects of the above-mentioned solution, please refer to the corresponding description in the first aspect. For the sake of brevity, this application will not repeat it here.

[0058] Optionally, the transceiver described above can be a transceiver circuit. Optionally, the input / output interface described above can be an input / output circuit.

[0059] Fifthly, an optical fiber communication system is provided, the system comprising: an optical amplifier station, the optical amplifier station including the optical fiber amplifier as described in the first aspect. Attached Figure Description

[0060] Figure 1 A schematic diagram illustrating an application scenario applicable to embodiments of this application is shown.

[0061] Figure 2 A schematic diagram of an optical fiber amplifier 200 provided in an embodiment of this application is shown.

[0062] Figure 3 A schematic diagram of an optical fiber amplifier 300 provided in an embodiment of this application is shown.

[0063] Figure 4 A schematic diagram of an optical fiber amplifier 400 provided in an embodiment of this application is shown.

[0064] Figure 5 A schematic diagram of an optical fiber amplifier 500 provided in an embodiment of this application is shown.

[0065] Figure 6 A schematic diagram of an optical fiber amplifier 600 provided in an embodiment of this application is shown.

[0066] Figure 7 A schematic diagram of an optical fiber amplifier 700 provided in an embodiment of this application is shown.

[0067] Figure 8 A schematic diagram of an optical fiber amplifier 800 provided in an embodiment of this application is shown.

[0068] Figure 9 A schematic diagram of a 4-core fiber optic amplifier 900 provided in an embodiment of this application is shown.

[0069] Figure 10 A schematic diagram of the core spacing before and after conversion provided in an embodiment of this application is shown.

[0070] Figure 11 A schematic diagram of a 4-core fiber optic amplifier 1100 provided in an embodiment of this application is shown.

[0071] Figure 12 A schematic diagram of the core spacing before and after conversion provided in an embodiment of this application is shown.

[0072] Figure 13 A schematic diagram of an optical fiber amplifier 1300 provided in an embodiment of this application is shown.

[0073] Figure 14 A schematic diagram of an optical fiber amplifier 1400 provided in an embodiment of this application is shown.

[0074] Figure 15 A schematic block diagram of a method 1500 for amplifying an optical signal according to an embodiment of this application is shown.

[0075] Figure 16 A schematic block diagram of a method 1600 for amplifying an optical signal provided in an embodiment of this application is shown. Detailed Implementation

[0076] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0077] The technical solutions of this application embodiment can be applied to optical fiber communication networks. For example, the technical solutions of this application embodiment can be used in optical fiber amplifiers in optical fiber communication networks. Optical fiber amplifiers are mainly located in optical amplifier stations and optical amplifier network elements in optical fiber communication networks. The technical solutions of this application embodiment can be used to implement optical fiber amplifiers composed of multi-core optical fibers.

[0078] Figure 1 This is a schematic diagram illustrating an application scenario applicable to embodiments of this application. In an optical fiber communication network, an optical terminal multiplexing (OTM) station may be included. The OTM may contain an optical forwarding unit, a wavelength multiplexer / demultiplexer array, a fan-in / fan-out unit, and an optical amplifier (OA). The optical forwarding unit further includes a transmitting side (Transmit(tx)) and a receiving side (Receive(rx)). An optical line amplifier (OLA) station mainly includes one or more OAs.

[0079] The optical forwarding unit carries service signals on specific wavelengths of light. In a multi-core fiber optic transmission system, if the transmission fiber is a randomly coupled multi-core fiber, it operates in a spatial hyperchannel configuration, where multiple subcarriers use the same wavelength and output from different fibers or cores. If the transmission fiber is a weakly coupled multi-core fiber, it can operate in a spatial hyperchannel, frequency hyperchannel, or single-carrier configuration. The wavelength multiplexer / demultiplexer functions to multiplex different wavelength signals onto a single-mode fiber or demultiplex different wavelength signals from a single-mode fiber. Fan-in / fan-out functions to multiplex multiple single-mode fibers into a multi-core fiber or demultiplex individual cores from a multi-core fiber into different single-mode fibers. The OA (Optical Outlet) function amplifies the optical signals in each core of the multi-core fiber, extending the transmission distance.

[0080] It should be understood that the above Figure 1 This is merely an illustrative example and is not intended to limit the scope of the application. For instance, optical fiber communication networks may include even more optical devices; furthermore, the embodiments of this application can be applied to any scenario that includes an optical fiber amplifier.

[0081] The various embodiments provided in this application will now be described in detail with reference to the accompanying drawings.

[0082] The following description is provided to facilitate understanding of the embodiments of this application.

[0083] In the embodiments shown below, the terms "first," "second," "third," "fourth," and various numerical designations are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. For example, they may distinguish different states of optical signals after different steps.

[0084] Figure 2 This is a schematic diagram of an optical fiber amplifier 200 according to an embodiment of this application. Figure 2 As shown, the amplifier 200 may include:

[0085] The first interpitch converter 220, the gain module 221, and the second interpitch converter 222.

[0086] A first-core-pitch converter 220 is used to receive a first optical signal transmitted by a first N-core optical fiber 210 and convert the first optical signal of the first N-core optical fiber 210 into a second optical signal transmitted by a second N-core optical fiber 211. The input end of the first-core-pitch converter 220 is connected to the output end of the first N-core optical fiber 210, and the output end of the first-core-pitch converter 220 is connected to the input end of the second N-core optical fiber 211.

[0087] It should be understood that the first N-core fiber 210 can be a section of fiber composed of the pigtail of the first core pitch converter 220 and the transmission fiber, and the second N-core fiber 211 can be a section of fiber composed of the pigtail of the first core pitch converter 220 and the transmission fiber, or a section of fiber composed of the pigtail of the first core pitch converter and the gain module.

[0088] Gain module 221 amplifies the second optical signal based on the first pump light to obtain a third optical signal. Gain module 221 receives the second optical signal via a second N-core optical fiber 211 and transmits the obtained third optical signal to the input of the second core-pitch converter 222 via an eighth N-core optical fiber. Similarly, the eighth N-core optical fiber 212 can be a section of optical fiber jointly formed by the pigtail of gain module 221 and the pigtail of the second core-pitch converter 222.

[0089] It should be understood that the gain module can also be used to obtain the first pump light mentioned above.

[0090] The second core-to-core pitch converter 222 is used to receive the third optical signal output by the gain module 221 and convert the third optical signal into a fourth optical signal transmitted by the third N-core optical fiber 213. The output end of the second core-to-core pitch converter 222 is connected to the third N-core optical fiber 213.

[0091] Similarly, the third N-core optical fiber can be a section of optical fiber composed of the pigtail of the second core pitch converter 222 and the pigtail of the transmission optical fiber or the component after the output of the amplifier.

[0092] The core spacing of the first N-core optical fiber 210 is the same as that of the third N-core optical fiber 213, and the core spacing of the second N-core optical fiber 211 is the same as that of the eighth N-core optical fiber 212, where N is an integer greater than 1.

[0093] In one feasible implementation, the core spacing of the first N-core fiber 210 is smaller than the core spacing of the second N-core fiber 211, while the core spacing of the eighth N-core fiber 212 is larger than the core spacing of the third N-core fiber 213. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter 220 increases from small to large, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter 222 decreases from large to large.

[0094] In this configuration, the first N-core fiber 210 and the third N-core fiber 212 can be randomly coupled N-core fibers or other types of N-core fibers, while the second N-core fiber 211 can be a weakly coupled N-core fiber or other types of N-core fibers. When the first N-core fiber 210 and the third N-core fiber 212 are randomly coupled N-core fibers, the inter-core spacing of these randomly coupled N-core fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber 211 can be a weakly coupled N-core fiber, and the inter-core spacing of this weakly coupled N-core fiber can be greater than 40 μm.

[0095] It should be understood that before an optical signal is input to an optical fiber amplifier, it typically travels through a relatively long transmission fiber, causing the gain between different modes to become roughly the same. In other words, the differential mode gain of the different modes of the first optical signal received by the first core-pitch converter is relatively small. At this point, because the core-pitch of the multi-core fiber at the output end of the first core-pitch converter is further increased, the modes carried by each fiber core become more independent and isolated from each other during the transmission and amplification of the optical signals in the optical fiber amplifier. This makes the crosstalk between the fiber cores very weak, or even negligible. Under these circumstances, the optical fiber amplifier can achieve the effect of weakly coupled multi-core amplification, which is suitable for signal amplification in coupled multi-core optical fiber transmission systems. The amplification performance of each core has little dependence on the spatial mode, thus effectively solving the problem of damage to transmission performance caused by differential mode gain or mode-dependent gain.

[0096] In one feasible implementation, the core spacing of the first N-core optical fiber 210 is greater than the core spacing of the second N-core optical fiber 211, while the core spacing of the eighth N-core optical fiber 212 is less than the core spacing of the third N-core optical fiber 213. That is, the core spacing of the optical fibers connected to the input and output ends of the first core spacing converter 220 decreases from large to small, and correspondingly, the core spacing of the optical fibers connected to the input and output ends of the second core spacing converter 222 increases from small to large.

[0097] In this configuration, the first N-core fiber 210 and the third N-core fiber 213 can be randomly coupled N-core fibers or other types of N-core fibers, and the second N-core fiber 211 can also be a randomly coupled N-core fiber or other types of N-core fibers. When the first N-core fiber 210 and the third N-core fiber 213 are randomly coupled N-core fibers, the inter-core spacing of these randomly coupled N-core fibers can be 17-25 μm or other ranges. In this case, the inter-core spacing of the randomly coupled N-core fibers that the second N-core fiber 211 can use can be 8-16 μm.

[0098] It should be noted that, in this case, since the inter-core spacing of the multi-core fiber at the output end of the first core-pitch converter is further reduced, the spatial channel density becomes higher, and the energy of the same mode can be distributed in different fiber cores. This allows the optical signals of each mode to generate a sufficient number of inter-mode energy couplings during the amplification process of the fiber amplifier. In other words, the coupling between each mode is enhanced, which is beneficial to reduce differential mode dispersion and to average the gain of each mode, thereby reducing the differential mode gain.

[0099] The amplifier provided in this application, by arranging a pair of core-pitch converters at the input and output of the fiber optic amplifier, is suitable for signal amplification in coupled multi-core fiber optic transmission systems and helps to reduce differential mode gain or mode-dependent gain, thereby improving transmission performance.

[0100] Figure 3 This is a schematic diagram of an optical fiber amplifier 300 according to an embodiment of this application. Figure 3 As shown, the amplifier 300 may include:

[0101] The first core pitch converter 320, the first module 321, the N-core gain fiber 312, and the second core pitch converter 322.

[0102] A first-core-pitch converter 320 is used to receive a first optical signal from a first N-core optical fiber 310 and convert the first optical signal from the first N-core optical fiber 310 into a second optical signal from a second N-core optical fiber 311. The input end of the first-core-pitch converter 320 is connected to the output end of the first N-core optical fiber 310, and the output end of the first-core-pitch converter 320 is connected to the input end of the second N-core optical fiber 311.

[0103] The first module 321 is used to couple the second optical signal with the first pump light to obtain a first coupled optical signal. The input end of the first module 321 is connected to the output end of the second N-core optical fiber 311, and the output end of the first module 321 is connected to the input end of the N-core gain optical fiber 312.

[0104] Optionally, the first module is also used to acquire the first pump light.

[0105] The N-core gain fiber 312 uses the first pump light in the first coupled optical signal to amplify the second optical signal in the first coupled optical signal, thereby obtaining the third optical signal of the N-core gain fiber 312.

[0106] The second core-to-core spacing converter 322 is used to receive the third optical signal from the N-core gain fiber 312 and convert the third optical signal output by the N-core gain fiber 312 into the fourth optical signal of the third N-core fiber 313. The input end of the second core-to-core spacing converter 322 is connected to the output end of the N-core gain fiber 312, and the output end of the second core-to-core spacing converter 322 is connected to the third N-core fiber 313.

[0107] The first N-core fiber 310 and the third N-core fiber 313 have the same core spacing, and the second N-core fiber 311 and the N-core gain fiber 312 have the same core spacing, where N is an integer greater than 1.

[0108] It should be noted that the composition of the first N-core optical fiber 310, the second N-core optical fiber 311, and the third N-core optical fiber 313 can be referenced above. Figure 2 The corresponding descriptions in the text will not be repeated here.

[0109] In one feasible implementation, the core spacing of the first N-core fiber 310 is smaller than the core spacing of the second N-core fiber 311, while the core spacing of the N-core gain fiber 312 is larger than the core spacing of the third N-core fiber 313. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter 320 increases from small to large, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter 322 decreases from large to large.

[0110] In this configuration, the first N-core fiber 310 and the third N-core fiber 313 can be randomly coupled N-core fibers or other types of N-core fibers, while the second N-core fiber 311 can be a weakly coupled N-core fiber or other types of N-core fibers. When the first N-core fiber 310 and the third N-core fiber 313 are randomly coupled N-core fibers, the inter-core spacing of these randomly coupled N-core fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber 311 can be a weakly coupled N-core fiber, and the inter-core spacing of this weakly coupled N-core fiber can be greater than 40 μm.

[0111] Similarly, as the inter-core spacing of the multi-core fiber at the output end of the first inter-core pitch converter is further increased, the modes carried by each fiber core become more independent and isolated from each other during the transmission and amplification of optical signals in the fiber amplifier. The crosstalk between the fiber cores is very weak and can even be ignored. Under these circumstances, the fiber amplifier can achieve the effect of weakly coupled multi-core amplification, which is suitable for signal amplification in coupled multi-core fiber transmission systems. The amplification performance of each core has little dependence on the spatial mode, thus effectively solving the problem of damage to transmission performance caused by differential mode gain or mode-dependent gain.

[0112] In one feasible implementation, the core spacing of the first N-core fiber 310 is greater than the core spacing of the second N-core fiber 311, while the core spacing of the N-core gain fiber 312 is smaller than the core spacing of the third N-core fiber 313. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter 320 decreases, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter 322 increases.

[0113] In this configuration, the first N-core fiber 310 and the third N-core fiber 313 can be randomly coupled N-core fibers or other types of N-core fibers, while the second N-core fiber 311 can be a fully randomly coupled N-core fiber or other types of N-core fibers. When the first N-core fiber 310 and the third N-core fiber 313 are randomly coupled N-core fibers, the inter-core spacing of these fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber 311 can be a fully randomly coupled N-core fiber, and the inter-core spacing of this weakly coupled N-core fiber can be 8-16 μm.

[0114] It should be noted that in this case, where the core spacing of the second N-core fiber 311 is smaller than that of the first N-core fiber 310, both the second N-core fiber 311 and the first N-core fiber 310 are randomly coupled fibers. However, due to the smaller core spacing of the second N-core fiber 311, the energy conversion between modes is relatively weak, similar to the situation in supermode fibers where aliasing does not occur between modes. In this case, the refractive index of the N-core gain fiber 312 can be designed, for example, by increasing the refractive index of the N-core gain fiber 312, to achieve phase matching between the modes of the optical signals in each fiber core of the amplified third optical signal, and to ensure sufficient energy aliasing.

[0115] Furthermore, the N-core gain fiber 312 can be a rare-earth-doped fiber, such as an erbium-doped fiber. The principle of this doped optical signal can be simply understood as follows: when the signal light and the pump light are simultaneously injected into the erbium fiber, the erbium ions are excited to a high energy level under the action of the pump light and quickly decay to a metastable energy level. When they return to the ground state under the action of the incident signal light, they emit photons corresponding to the signal light, thus amplifying the signal.

[0116] It should be understood that the N-core gain fiber 312 can also be an N-core fiber that achieves amplification using other principles, and this application does not limit it.

[0117] The amplifier provided in this application, by arranging a pair of core-pitch converters, constitutes a weakly coupled multi-core fiber amplifier or a fully randomly coupled multi-core fiber amplifier, which helps to reduce the impairment of transmission performance caused by differential mode gain or mode-dependent gain. Simultaneously, it achieves decoupling between the transmission fiber and the amplifier design. As long as the number of cores in the coupled multi-core transmission fiber is the same, different core pitches or geometric arrangements only require changing the design of the core-pitch converters; the other amplifier designs can remain unchanged. This allows for full sharing of the device supply chain, which is beneficial for the normalization of space-division optical passive devices and components, doped fibers, cost reduction, and shortened development cycles. Furthermore, the weakly coupled multi-core transmission fiber can also be used in conjunction with the multi-core fiber amplifier provided in this application.

[0118] Depending on the different designs of the first module, the amplifier 200 provided in this application embodiment may further include the following: Figure 4 The amplifier 400 shown and Figure 8 The amplifier shown is 800.

[0119] Next, for Figure 4 The amplifier 400 shown and Figure 8 The amplifier 800 shown will be described separately.

[0120] Figure 4 This is a schematic diagram of the fiber optic amplifier 400 provided in an embodiment of this application. Figure 4 As shown, the amplifier 400 may include:

[0121] The system comprises a first core-to-core pitch converter 420, a first multiplexer 421, a first pump light fan-in converter 422, a first laser group 423, an N-core gain fiber 412, and a second core-to-core pitch converter 424.

[0122] A first-core-pitch converter 420 is used to receive a first optical signal transmitted by a first N-core optical fiber 410 and convert the first optical signal of the first N-core optical fiber 410 into a second optical signal transmitted by a second N-core optical fiber 411. The input end of the first-core-pitch converter 420 is connected to the output end of the first N-core optical fiber 410, and the output end of the first-core-pitch converter 420 is connected to the input end of the second N-core optical fiber 411.

[0123] The first laser group 423 may include N pump lasers for generating N second pump beams and coupling the N second pump beams into the first pump beam fan-inductor 422 through N first single-core optical fibers 431.

[0124] The first pump light fan-in unit 422 receives N second pump lights output from the first single-core fiber 431 and couples the N second pump lights to generate a first pump light. The first pump light is then coupled into the fourth N-core fiber 314. The output end of the first pump module 422 is connected to the input end of the fourth N-core fiber 414.

[0125] The first combiner 421 receives the first pump light output from the fourth N-core optical fiber 414 and couples the second optical signal with the first pump light to generate a first coupled optical signal. The input end of the combiner 421 is connected to the output end of the fourth N-core optical fiber 414, and the output end of the combiner 421 is connected to the input end of the N-core gain optical fiber.

[0126] The N-core gain fiber 412 amplifies the second optical signal in the first coupled optical signal using the first pump light in the first coupled optical signal, thereby obtaining the third optical signal output by the N-core gain fiber 412.

[0127] The second core-to-core spacing converter 424 is used to receive the third optical signal transmitted by the N-core gain fiber 412 and convert the third optical signal output by the N-core gain fiber 412 into a fourth optical signal transmitted by the third N-core fiber 413. The input end of the second core-to-core spacing converter 424 is connected to the output end of the N-core gain fiber 412, and the output end of the second core-to-core spacing converter 424 is connected to the third N-core fiber 413.

[0128] It should be understood that the core spacing of the fourth N-core fiber 414 can be the same as that of the second N-core fiber 411 and the N-core doped fiber 412, or it can use other core spacings. When the core spacing of the fourth N-core fiber 414 is other, the combiner 421 can be configured as a special combiner capable of coupling the second optical signal in the second N-core fiber 411 with the first pump light in the fourth N-core fiber 414, that is, coupling the optical signal in each core of the second N-core fiber 411 with the pump light in each core of the fourth N-core fiber 414 one by one. The N-core gain fiber 412 can be an N-core doped fiber, such as erbium-doped fiber, or other types of fiber. The first N-core fiber 410 and the third N-core fiber 413 have the same core spacing, where N is an integer greater than 1.

[0129] In one feasible implementation, the core spacing of the first N-core fiber 410 is smaller than that of the second N-core fiber 411, while the core spacing of the N-core gain fiber 412 is larger than that of the third N-core fiber 413. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter 420 increases from small to large, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter 424 decreases from large to large. In this case, the first N-core fiber 410 and the third N-core fiber 413 can be randomly coupled N-core fibers or other types of N-core fibers, and the second N-core fiber 411 can be a weakly coupled N-core fiber or other types of N-core fibers. When the first N-core fiber 410 and the third N-core fiber 413 are randomly coupled N-core fibers, the core spacing range of the randomly coupled N-core fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber 411 can be a weakly coupled N-core fiber, and the core spacing range of the weakly coupled N-core fiber can be greater than 40 μm.

[0130] At this time, during the transmission and amplification of optical signals of various modes in the fiber amplifier, the modes carried by each fiber core are independent and isolated from each other, and the crosstalk between the fiber cores is very weak. Under these circumstances, the fiber amplifier can achieve the effect of weakly coupled multi-core amplification, which is suitable for signal amplification in coupled multi-core fiber transmission systems. The amplification performance of each core has little dependence on the spatial mode, thus effectively solving the damage to transmission performance caused by differential mode gain or mode-dependent gain.

[0131] In one feasible implementation, the core spacing of the first N-core fiber 410 is greater than that of the second N-core fiber 411, while the core spacing of the N-core gain fiber 412 is smaller than that of the third N-core fiber 413. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter 420 decreases, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter 424 increases. In this case, the first N-core fiber 410 and the third N-core fiber 413 can be randomly coupled N-core fibers or other types of N-core fibers, and the second N-core fiber 411 can be a randomly coupled N-core fiber with a smaller core spacing or another type of N-core fiber. When the first N-core fiber 410 and the third N-core fiber 413 are randomly coupled N-core fibers, the core spacing range of the randomly coupled N-core fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber 411 can be a randomly coupled fiber with a core spacing range of 8-16 μm.

[0132] It should be noted that in this case, where the core spacing of the second N-core fiber 411 is smaller than that of the first N-core fiber 410, both the second N-core fiber 411 and the first N-core fiber 410 are randomly coupled fibers. However, due to the smaller core spacing of the second N-core fiber 411, the energy conversion between modes is relatively weak, similar to the situation in supermode fibers where aliasing does not occur between modes. In this case, the refractive index of the N-core gain fiber 412 can be designed, for example, by increasing the refractive index of the N-core gain fiber 412, to achieve phase matching between the modes of the optical signals in each fiber core of the amplified third optical signal, and to ensure sufficient energy aliasing.

[0133] Furthermore, it should be understood that in this embodiment, the composition of the first N-core optical fiber 410, the second N-core optical fiber 411, and the third N-core optical fiber 413 can refer to the above description. Figure 2 or Figure 3 The corresponding descriptions in the text will not be repeated here.

[0134] The amplifier provided in this application has a consistent optical layer for the core signal path of the multi-core optical fiber, which avoids the problem of time delay difference accumulation. This resolves many limitations caused by time delay difference accumulation, such as increased complexity in received signal processing, power consumption, switching delay, and maintenance. Furthermore, the use of a core-pumped design allows for individual control of the amplification performance of each core, ensuring consistency in amplification performance between cores and improving practicality.

[0135] Figure 5 This is a schematic diagram of the fiber optic amplifier 500 provided in an embodiment of this application. Figure 5 As shown, the amplifier 500 can... Figure 4 A first N-core optical isolator 525 is added to the amplifier 400 shown.

[0136] It should be understood that in an amplifier or a system that includes an amplifier, there are other components at the output end of the gain fiber. Even if these components are tightly coupled to the connected gain fiber, some light may be reflected back into the gain fiber after passing through the components. Therefore, a first N-core optical isolator 525 can be arranged at the output end of the gain fiber to isolate the reflected light from the output end of the gain fiber, thereby preventing the reflected light from entering the gain fiber and causing changes in key performance indicators such as the noise figure.

[0137] The first N-core optical isolator 525 can be placed between the N-core gain fiber 512 and the second core-pitch converter 524. The input end of the first N-core optical isolator 525 is connected to the output end of the N-core gain fiber 512, meaning that the first N-core optical isolator 525 processes the received third optical signal to obtain the fifth optical signal. The output end of the first N-core optical isolator 525 is connected to the second core-pitch converter 524 through the fifth N-core fiber.

[0138] It should be understood that the core spacing of the fifth N-core fiber 515 should be consistent with the core spacing of the N-core gain fiber 512.

[0139] It should be noted that the other components of this amplifier 500 can be referenced as described above. Figure 2 or the above Figure 3 or the above Figure 4 The descriptions of the corresponding components will not be repeated here.

[0140] Based on the above solution, the amplifier provided in this application can isolate the influence of reflected light at the output end on the amplification effect of the gain fiber, thereby improving the quality of the output optical signal.

[0141] Figure 6 This is a schematic diagram of another fiber optic amplifier 600 provided in an embodiment of this application. Figure 6 As shown, the amplifier 600 can... Figure 5 A second N-core optical isolator 626 is added to the amplifier 500 shown.

[0142] It should be understood that in an optical fiber amplifier, as activated particles return from the excited state to the ground state and amplify the optical signal, random incoherent spontaneous emission of stimulated particles is also generated. This spontaneous emission can occur in any direction and can induce further stimulated emission, which can be amplified. In short, amplification of non-signal frequency bands will be generated during the amplification process, namely amplifier spontaneous emission (ASE) noise. This ASE noise can leak from the input end of the gain fiber, thereby affecting the performance of the front-end components. Therefore, a second N-core optical isolator 526 can be placed at the input end of the gain fiber to isolate the ASE noise leaking from the input end of the gain fiber.

[0143] The second N-core optical isolator 626 can be placed between the first core-pitch converter 620 and the multiplexer 621. The output of the first core-pitch converter 620 is connected to the second N-core optical isolator 626 via a second N-core optical fiber 611. The second N-core optical fiber 611 transmits the second optical signal to the second N-core optical isolator 626, and after processing by the second N-core optical isolator 626, a sixth optical signal is obtained. The output of the second N-core optical isolator 626 is connected to the input of the sixth N-core optical fiber, and the sixth optical signal is transmitted to the multiplexer 621 via the sixth N-core optical fiber. At the multiplexer 621, it is coupled with the first coupling pump optical signal from the fourth N-core optical fiber 614 to generate a first coupled optical signal.

[0144] It should be understood that the core spacing of the sixth N-core fiber 616 should be consistent with the core spacing of the second N-core fiber 611.

[0145] Furthermore, other components of the amplifier 600 can be found in the above description. Figure 2 or the above Figure 3 or the above Figure 4 or the above Figure 5 The descriptions of the corresponding components are not repeated here.

[0146] Based on the above solution, the amplifier provided in this application can eliminate the reverse ASE noise at the input end of the gain fiber, and at the same time isolate the influence of the reflected light at the output end on the amplification effect of the gain fiber, thereby improving the quality of the output optical signal.

[0147] Figure 7 This is a schematic diagram of another fiber optic amplifier 700 provided in an embodiment of this application. Figure 7 As shown, amplifier 00 can... Figure 6 A gain-flattening filter 727 is added to the amplifier 600 shown.

[0148] It should be understood that, constrained by the emission spectrum of erbium ions, the output spectrum of erbium-doped fiber light sources has two asymmetric peaks appearing near 1531 nm and 1558 nm, respectively. In practical applications, a flatter gain spectrum is often required. Therefore, a gain-flattening filter 727 can be added to the system, causing the filter's transmittance value to change with wavelength. Wavelength signals with higher gain correspond to lower transmittance values, and vice versa. In this way, signals with different wavelengths in each fiber core can achieve gain equalization after passing through the gain-flattening filter 727, resulting in a flat spectrum.

[0149] The gain-flattening filter 727 can be placed between the first N-core optical isolator 725 and the second core-pitch converter 724. The output of the first N-core optical isolator 725 is connected to the gain-flattening filter 727 via a fifth N-core optical fiber 715. The fifth N-core optical fiber 715 transmits the fifth optical signal to the gain-flattening filter 727, and after processing by the gain-flattening filter 727, a seventh optical signal is obtained. The output of the gain-flattening filter 727 is connected to the input of the seventh N-core optical fiber 717, and the seventh optical signal is transmitted to the second core-pitch converter 724 via the seventh N-core optical fiber 717.

[0150] It should be understood that the core spacing of the seventh N-core fiber 717 should be consistent with the core spacing of the N-core gain fiber 712.

[0151] Furthermore, other components of the amplifier 700 can be referenced above. Figure 2 or the above Figure 3 or the above Figure 4 or the above Figure 5 or the above Figure 6 The descriptions of the corresponding components are not repeated here.

[0152] Based on the above solution, the amplifier provided in this application can equalize the wavelength-dependent gain of the amplifier gain medium to a basically consistent value, thereby improving the quality of the output optical signal.

[0153] It should be noted that the above Figure 5 , Figure 6 , Figure 7 All are in Figure 4 In addition to the existing components, other parts were added to improve amplifier performance. It should be understood that the combination of these components is not limited to... Figure 5 , Figure 6 , Figure 7 The embodiments shown are not limited to the scope of protection of this application. Figure 5 , Figure 6 , Figure 7 It should be understood that... Figure 5 , Figure 6 , Figure 7 Any component in Figure 4Any combination based on the structure should be within the scope of protection of this application.

[0154] Furthermore, it should be understood that, as in this application Figure 4 Any additional components that improve amplifier performance based on the above should be within the scope of protection of this application.

[0155] Figure 8 This is a schematic diagram of the fiber optic amplifier 800 provided in an embodiment of this application. Figure 8 As shown, the amplifier 800 may include:

[0156] First core pitch converter 820, second combiner 821, first pump laser 822, N-core gain fiber 813, second core pitch converter 823.

[0157] A first-core-pitch converter 820 is used to receive a first optical signal transmitted by a first N-core optical fiber 810 and convert the first optical signal transmitted by the first N-core optical fiber 810 into a second optical signal transmitted by a second N-core optical fiber 811. The input end of the first-core-pitch converter 820 is connected to the output end of the first N-core optical fiber 810, and the output end of the first-core-pitch converter 820 is connected to the input end of the second N-core optical fiber 811.

[0158] The second multiplexer 821 receives a second optical signal transmitted from the second N-core optical fiber 811 and a first pump light transmitted from the fourth single-core optical fiber 812, and couples the second optical signal and the first pump light to generate a first coupled optical signal. The input of the second multiplexer 821 is connected to the output of both the second N-core optical fiber 811 and the fourth single-core optical fiber 812. The output of the second multiplexer is connected to the input of the N-core gain optical fiber 813.

[0159] The first pump laser 822 is used to generate the first pump light and input the first pump light into the second combiner 821 through the fourth single-core optical fiber 812.

[0160] The N-core gain fiber 813 amplifies the second optical signal in the first coupled optical signal using the first pump light in the first coupled optical signal, thus obtaining the amplified signal of the N-core gain fiber 813, namely the third optical signal.

[0161] It should be noted that the N-core gain fiber 813 can be a double-clad multi-core doped fiber, with the core covered by the inner cladding. The core provides doping (such as erbium doping), and the doped ions amplify the input second optical signal after absorbing the first pump light. The inner cladding is used for coupling and transmitting the multimode first pump light, which is absorbed by the doped ions when it passes through the core in the inner cladding.

[0162] The second core-to-core spacing converter 823 is used to receive the third optical signal output from the N-core gain fiber 813 and convert the third optical signal output from the N-core gain fiber 813 into a fourth optical signal from the third N-core fiber 814. The input end of the second core-to-core spacing converter 823 is connected to the output end of the N-core gain fiber 813, and the output end of the second core-to-core spacing converter 823 is connected to the third N-core fiber 814.

[0163] It should be understood that the composition of the first N-core optical fiber 810, the second N-core optical fiber 811, and the third N-core optical fiber 814 can be referenced as described above. Figure 2 or Figure 3 The corresponding descriptions in the text will not be repeated here.

[0164] In summary, combining Figures 3 to 8 The amplifier structures under different first modules are described. It should be understood that in the embodiments of this application, both the first and second core-pitch converters are used to convert the core pitch of the optical signal in the input N-core optical fiber to the core pitch of the output N-core optical fiber. When the core pitch of the optical fiber from the input to the output of the first core-pitch converter is converted from a small core pitch to a large core pitch, the core pitch of the optical fibers connected before and after the second core-pitch converter will decrease from large to small. Conversely, when the core pitch of the optical fiber from the input to the output of the first core-pitch converter is converted from a large core pitch to a small core pitch, the core pitch of the optical fibers connected before and after the second core-pitch converter will increase from small to large.

[0165] It should be understood that the core spacing of the N-core optical fibers from the output of the first core spacing converter to the input of the second core spacing converter should remain consistent.

[0166] In a specific embodiment, such as Figure 9 The schematic diagram of amplifier 900 shown uses a 4-core optical fiber as the transmission fiber. In this case, the input fiber of the first core-pitch converter can be a randomly coupled 4-core optical fiber, and the core pitch of this fiber can be... Figure 10 As shown in 10(a) of the diagram, the output fiber of the first core-pitch converter can be a weakly coupled 4-core fiber with a core pitch of 20 μm. Figure 10 The 40 μm shown in 10(b) is relevant. Correspondingly, the input fiber with the second core pitch can be weakly coupled to a 4-core fiber, the core pitch of which can be... Figure 10 As shown in 10(b), the output fiber of the second core-pitch converter can be a randomly coupled 4-core fiber with a core pitch of 40 μm. Figure 10 The 20 μm shown in 10(a) is shown in the figure.

[0167] It should be understood that, Figure 9In the amplifier shown, the core spacing of all multi-core optical fibers located between the first core spacing converter and the second core spacing converter is the same as the core spacing of the four-core optical fibers connected to the output end of the first core spacing converter or the core spacing of the four-core optical fibers connected to the input end of the second core spacing converter.

[0168] It should be noted that, Figure 9 The adoption of only the first module is as follows Figure 4 The first form shown is illustrated by example. It should be understood that, in the embodiments of this application, the first module is adopted as follows: Figure 8 As shown, the above description of the fiber core spacing still applies.

[0169] Based on the above Figure 10 The shown design includes the intercore spacing of a multi-core optical fiber. Figure 9 The optical amplifier 900 shown can achieve weakly coupled multi-core amplification, making it suitable for signal amplification in coupled multi-core fiber optic transmission systems. Each core is amplified independently, and the amplification performance has very little dependence on the spatial mode, thus effectively solving the problem of differential mode gain / mode-dependent gain degrading transmission performance.

[0170] In another specific embodiment, such as Figure 11 The schematic diagram of amplifier 1100 shown uses a 4-core optical fiber as the transmission fiber. In this case, the input fiber of the first core-pitch converter can be a randomly coupled 4-core optical fiber, and the core pitch of this fiber can be... Figure 12 As shown in 12(a), the output fiber of the first core-pitch converter can be a fully randomly coupled 4-core fiber with a core pitch of 20 μm. Figure 12 The 10 μm shown in 12(b) indicates this. Correspondingly, the input fiber with the second core pitch can be sufficiently randomly coupled to a 4-core fiber, the core pitch of which can be... Figure 12 As shown in 12(b), the output fiber of the second core-pitch converter can be a randomly coupled 4-core fiber with a core pitch of 10 μm. Figure 12 The 20 μm shown in 12(a) is shown in the figure.

[0171] It should be understood that, Figure 11 In the amplifier shown, the core spacing of all multi-core optical fibers located between the first core spacing converter and the second core spacing converter is the same as the core spacing of the four-core optical fibers connected to the output end of the first core spacing converter or the core spacing of the four-core optical fibers connected to the input end of the second core spacing converter.

[0172] It should be noted that, Figure 11 The adoption of only the first module is as follows Figure 4 The first form shown is illustrated by example. It should be understood that, in the embodiments of this application, the first module is adopted as follows: Figure 8 As shown, the above description of the fiber core spacing still applies.

[0173] Based on the above Figure 12 The fiber core spacing design shown is as follows: Figure 11 The optical amplifier 1100 shown can achieve random coupling multi-core amplification effect, which is suitable for signal amplification in coupled multi-core optical fiber transmission systems. During the amplification process, each supermode generates random energy coupling, which helps to reduce differential mode dispersion and thus helps to reduce the damage to transmission performance caused by differential mode gain / mode correlation gain.

[0174] Figure 13 This is a schematic diagram of an optical fiber amplifier 1300 according to an embodiment of this application. Figure 13 As shown, the amplifier 1300 may include:

[0175] First core pitch converter 1320, first module 1321, N-core gain fiber 1312, second module 1322, second core pitch converter 1323.

[0176] like Figure 13 As shown, the amplifier 1300 is in Figure 2 A second module 1322 was added to the amplifier 200 shown.

[0177] The second module 1322 is used to acquire N channels of third pump light. The second module 1322 can form a bidirectional pumping structure with the first module 1321.

[0178] It should be understood that the pump laser is typically connected to a pump / signal wavelength division multiplexer on the input side of the erbium-doped fiber, forming a forward pumping structure. This provides sufficient pump power on the input side of the erbium-doped fiber, resulting in a high population inversion rate and a relatively low noise figure. When the system does not have high requirements for the noise figure of the optical amplifier, the pump laser can also be connected to a pump / signal wavelength division multiplexer on the output side of the erbium-doped fiber, forming a reverse pumping structure. The advantage of the reverse pumping structure is its relatively high pump power conversion efficiency and reduced pump power consumption. When an additional set of pump lasers is added to form a bidirectional pumping structure, the system can balance the noise figure and improve the power conversion efficiency.

[0179] In a specific implementation, such as Figure 14 In the schematic diagram of amplifier 1400 shown, the second module of amplifier 1400 adopts the following... Figure 4 The first form of the first module shown is illustrated by example. At this time, in Figure 14 In the amplifier 1400 shown, the first module is... Figure 4 The first module shown is the same.

[0180] It should be understood that Figure 13 The first and second modules of the amplifier 1300 shown can both adopt the following... Figure 4 The amplifier 400 shown Figure 8 The amplifier 800 shown corresponds to the first module, but it should be noted that in the same device, the first module and the corresponding second module should adopt the same pump structure.

[0181] like Figure 14 As shown, the amplifier 1400 may include:

[0182] The system comprises a first core-to-core pitch converter 1420, a first multiplexer 1421, a first laser group 1422, a first pump fan-in 1423, a wavelength division multiplexer 1424, a second laser group 1425, a second pump fan-in 1426, a second core-to-core pitch converter 1427, and a gain fiber 1412.

[0183] A first-core-pitch converter 1420 is used to receive a first optical signal transmitted by a first N-core optical fiber 1410 and convert the first optical signal of the first N-core optical fiber 1410 into a second optical signal transmitted by a second N-core optical fiber 1411. The input end of the first-core-pitch converter 1420 is connected to the output end of the first N-core optical fiber 1410, and the output end of the first-core-pitch converter 1420 is connected to the input end of the second N-core optical fiber 1411.

[0184] It should be understood that the first N-core fiber 1410 can be a section of fiber composed of the pigtail of the first core pitch converter 1420 and the transmission fiber, and the second N-core fiber 1411 can be a section of fiber composed of the pigtail of the first core pitch converter 1420 and the transmission fiber, or a section of fiber composed of the pigtail of the first core pitch converter and the gain module.

[0185] The first laser group 1422 is used to generate N second pump beams and transmit the N second pump beams to the first pump beam fan-in unit 1423 through N first single-core optical fibers 1431.

[0186] The first pump light fan-in receiver 1423 receives N second pump lights output from the first single-core fiber 1431, couples the N second pump lights to generate a first pump light, and pumps the first pump light into the fourth N-core fiber 1413. The output end of the first pump light fan-in receiver 1423 is connected to the input end of the fourth N-core fiber 1413.

[0187] The first multiplexer 1421 receives the first pump light output from the fourth N-core optical fiber 1413 and couples the second optical signal with the first pump light to generate a first coupled optical signal. The input end of the first multiplexer 1421 is connected to the output end of the fourth N-core optical fiber 1413, and the output end of the first multiplexer 1421 is connected to the input end of the N-core gain optical fiber.

[0188] The N-core gain fiber 1412 amplifies the second optical signal in the first coupled optical signal using the first pump light in the first coupled optical signal, thereby obtaining the third optical signal output by the N-core gain fiber 1412.

[0189] The second laser group 1425 is used to generate N third pump beams and transmit the N third pump beams to the second pump beam fan-in unit 1423 through N second single-core optical fibers 1432.

[0190] The second pump light fan-in receiver 1426 receives N third pump lights output from the second single-core fiber 1432 and couples the N third pump lights to generate a fourth pump light. The fourth pump light is then pump-coupled into the fifth N-core fiber 1414. The output end of the second pump light fan-in receiver 1426 is connected to the input end of the fifth N-core fiber 1414.

[0191] The wavelength division multiplexer 1424 receives the fourth pump light output from the fifth N-core fiber 1414 and reverses the fourth pump light into the N-core fiber 1412. Simultaneously, it outputs an eighth optical signal amplified by bidirectional pumping through the gain fiber 1412. The input of the wavelength division multiplexer 1424 is connected to the output of the fifth N-core fiber 1414, and the output of the wavelength division multiplexer 1424 is connected to the input of the ninth N-core fiber.

[0192] The second fiber pitch converter 1427 is used to receive the eighth optical signal output from the fifth N-core fiber 1414 and convert the eighth optical signal output from the fifth N-core fiber 1414 into the fourth optical signal transmitted by the third N-core fiber 1416. The input end of the second fiber pitch converter 1427 is connected to the output end of the fifth N-core fiber 1414, and the output end of the second fiber pitch converter 1427 is connected to the input end of the third N-core fiber 1416.

[0193] Similarly, the third N-core optical fiber can be a section of optical fiber composed of the pigtail of the second core pitch converter 1427 and the pigtail of the transmission optical fiber or the component after the output of the amplifier.

[0194] It should be understood that the core spacing of the fourth N-core fiber 1413 can be the same as that of the second N-core fiber 1411 and the N-core doped fiber 1412, or the core spacing of the fourth N-core fiber 1413 can be other core spacings. In this case, the combiner 421 can be configured as a special combiner, capable of coupling the second optical signal in the second N-core fiber 1411 with the first coupled pump light in the fourth N-core fiber 1413, that is, coupling the optical signal in each core of the second N-core fiber 1411 with the pump light in each core of the fourth N-core fiber 1413 one by one. The N-core gain fiber 1412 can be an N-core doped fiber, such as erbium-doped fiber, or other types of fiber. The core spacing of the first N-core fiber 1410 and the third N-core fiber 1416 is the same, where N is an integer greater than 1.

[0195] Similarly, the core spacing of the fifth N-core fiber 1414 can be the same as that of the ninth N-core fiber 1415 and the N-core doped fiber 1412, or it can use other core spacings. In this case, the wavelength division multiplexer 1424 can be configured as a special wavelength division multiplexer, capable of coupling the fourth pump light in the fifth N-core fiber 1414 to the N-core doped fiber 1412, that is, coupling the pump light in each core of the fifth N-core fiber 1414 into the core of the N-core doped fiber 1412 one by one. The N-core gain fiber 1412 can be an N-core doped fiber, such as erbium-doped fiber, or other types of fiber. The core spacing of the first N-core fiber 1410 and the third N-core fiber 1416 is the same, where N is an integer greater than 1.

[0196] In one feasible implementation, the core spacing of the first N-core fiber 1410 is smaller than the core spacing of the second N-core fiber 1411, while the core spacing of the N-core gain fiber 1412 is larger than the core spacing of the third N-core fiber 1416. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter 1420 increases from small to large, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter 1427 decreases from large to large.

[0197] In this configuration, the first N-core fiber 1410 and the third N-core fiber 1416 can be randomly coupled N-core fibers or other types of N-core fibers, while the second N-core fiber 1411 can be a weakly coupled N-core fiber or other types of N-core fibers. When the first N-core fiber 1410 and the third N-core fiber 1417 are randomly coupled N-core fibers, the inter-core spacing of these randomly coupled N-core fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber 1411 can be a weakly coupled N-core fiber, and the inter-core spacing of this weakly coupled N-core fiber can be greater than 40 μm.

[0198] It should be understood that before an optical signal is input to an optical fiber amplifier, it typically travels through a relatively long transmission fiber, causing the gain between different modes to become roughly the same. In other words, the differential mode gain of the different modes of the first optical signal received by the first core-pitch converter is relatively small. At this point, because the core-pitch of the multi-core fiber at the output end of the first core-pitch converter is further increased, the modes carried by each fiber core become more independent and isolated from each other during the transmission and amplification of the optical signals in the optical fiber amplifier. This makes the crosstalk between the fiber cores very weak, or even negligible. Under these circumstances, the optical fiber amplifier can achieve the effect of weakly coupled multi-core amplification, which is suitable for signal amplification in coupled multi-core optical fiber transmission systems. The amplification performance of each core has little dependence on the spatial mode, thus effectively solving the problem of damage to transmission performance caused by differential mode gain or mode-dependent gain.

[0199] In one feasible implementation, the core spacing of the first N-core fiber 1410 is greater than the core spacing of the second N-core fiber 1411, while the core spacing of the N-core gain fiber 1412 is less than the core spacing of the third N-core fiber 1416. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter 1420 decreases, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter 1427 increases.

[0200] In this configuration, the first N-core fiber 1410 and the third N-core fiber 1416 can be randomly coupled N-core fibers or other types of N-core fibers, while the second N-core fiber 1411 can be a randomly coupled N-core fiber with a smaller core pitch or another type of N-core fiber. When the first N-core fiber 1410 and the third N-core fiber 1416 are randomly coupled N-core fibers, the core pitch of these fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber 1411 can be a randomly coupled fiber with a core pitch range of 8-16 μm.

[0201] It should be noted that, in this case, since the inter-core spacing of the multi-core fiber at the output end of the first core-pitch converter is further reduced, the spatial channel density becomes higher, and the energy of the same mode can be distributed in different fiber cores. This allows the optical signals of each mode to generate a sufficient number of inter-mode energy couplings during the amplification process of the fiber amplifier. In other words, the coupling between each mode is enhanced, which is beneficial to reduce differential mode dispersion and to average the gain of each mode, thereby reducing the differential mode gain.

[0202] The amplifier provided in this application, by placing a pair of core-pitch converters at the input and output of the fiber amplifier, is suitable for signal amplification in coupled multi-core fiber optic transmission systems and helps to reduce differential mode gain or mode-dependent gain, thereby improving transmission performance. Simultaneously, adding a set of pump lasers to the gain fiber output of the fiber amplifier to form a bidirectional pump structure can balance the noise figure while improving power conversion efficiency.

[0203] The above, combined with Figures 2 to 14 The possible structures of the amplifiers provided in the embodiments of this application are described in detail. The following, in conjunction with... Figures 15 to 16 This application provides a detailed description of the method for amplifying optical signals.

[0204] Figure 15 A schematic block diagram of a method 1500 for amplifying optical signals according to an embodiment of this application is shown, such as... Figure 15 As shown, the method specifically includes:

[0205] S1501 converts the first optical signal transmitted through the first N-core optical fiber into a second optical signal transmitted through the second N-core optical fiber.

[0206] Specifically, the first core-pitch converter receives a first optical signal from a first N-core optical fiber and converts the first optical signal into a second optical signal from a second N-core optical fiber.

[0207] S1502 uses the first pump light to amplify the second optical signal, thereby obtaining the third optical signal output by the gain module.

[0208] Specifically, the gain module receives the second optical signal transmitted through the second N-core optical fiber and uses the first pump light to obtain an amplified third optical signal.

[0209] It should be understood that the gain module also needs to acquire the first pump light.

[0210] S1503 converts the third optical signal into a fourth optical signal transmitted through the third N-core optical fiber.

[0211] Specifically, the second core-pitch converter receives the third signal output by the gain module and converts the third optical signal into a fourth optical signal transmitted through the third N-core optical fiber.

[0212] Among them, the core spacing of the first N-core optical fiber and the third N-core optical fiber is the same, and the core spacing of the first N-core optical fiber and the second N-core optical fiber is different, where N is an integer greater than 1.

[0213] It should be noted that this N-core gain fiber can be a rare-earth-doped fiber, such as erbium-doped fiber or other types of fiber. The principle of this doped optical signal can be simply understood as follows: when the signal light and the pump light are injected into the erbium fiber simultaneously, the erbium ions are excited to a high energy level under the action of the pump light, and quickly decay to a metastable energy level. When they return to the ground state under the action of the incident signal light, they emit photons corresponding to the signal light, thus amplifying the signal.

[0214] In one feasible implementation, the core spacing of the first N-core fiber is smaller than that of the second N-core fiber, while the core spacing of the N-core gain fiber is larger than that of the third N-core fiber. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter increases from small to large, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter decreases from large to large.

[0215] In this configuration, the first and third N-core fibers can be randomly coupled N-core fibers or other types of N-core fibers, while the second N-core fiber can be a weakly coupled N-core fiber or another type of N-core fiber. When the first and third N-core fibers are randomly coupled N-core fibers, the inter-core spacing of the randomly coupled N-core fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber can be a weakly coupled N-core fiber, and the inter-core spacing of the weakly coupled N-core fiber can be greater than 40 μm.

[0216] In one feasible implementation, the core spacing of the first N-core fiber is greater than that of the second N-core fiber, while the core spacing of the N-core gain fiber is less than that of the third N-core fiber. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter decreases, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter increases.

[0217] In this configuration, the first and third N-core fibers can be randomly coupled N-core fibers or other types of N-core fibers, while the second N-core fiber can be a randomly coupled N-core fiber with a smaller core pitch or another type of N-core fiber. When the first and third N-core fibers are randomly coupled N-core fibers, the core pitch range can be 17-25 μm or other ranges. In this case, the second N-core fiber can be a randomly coupled fiber with a core pitch range of 8-16 μm.

[0218] The method for amplifying optical signals provided in this application embodiment changes the inter-core spacing of a multi-core optical fiber by deploying a pair of inter-core pitch converters, so that the optical signal forms a weakly coupled amplifier or is sufficiently randomly coupled and amplified during transmission, which helps to reduce the damage to transmission performance caused by differential mode gain or mode-dependent gain.

[0219] Figure 16 A schematic block diagram of a method 1600 for amplifying optical signals according to an embodiment of this application is shown, such as... Figure 16 As shown, the method specifically includes:

[0220] S1601 receives the first optical signal transmitted from the first N-core optical fiber.

[0221] Specifically, the first core pitch converter receives the first optical signal from the first N-core optical fiber.

[0222] S1602 converts the first optical signal into a second optical signal from the second N-core optical fiber.

[0223] Specifically, the first core-pitch converter converts the first optical signal into a second optical signal from the second N-core optical fiber.

[0224] S1603 generates N channels of second pump light.

[0225] Specifically, N lasers can be used to generate N second pump beams.

[0226] S1604 couples N second pump lights into the fourth N-core optical fiber to generate the first pump light.

[0227] Specifically, the pump light fan-in receives N second pump lights output from N lasers through N single-core optical fibers, and couples the N second pump lights into a fourth N-core optical fiber to generate the first pump light.

[0228] S1605, the second optical signal is coupled with the first pump light to obtain the first coupled optical signal.

[0229] Specifically, after the first module acquires the first pump light and receives the second optical signal, it couples the second optical signal with the first pump light to obtain the first coupled optical signal.

[0230] S1606, the second optical signal in the first coupled optical signal is amplified by the first pump light in the first coupled optical signal to obtain the third optical signal output by the N-core gain optical fiber.

[0231] Specifically, after receiving the first coupled optical signal output from the output end of the first module, the N-core gain optical fiber amplifies the second optical signal in the first coupled optical signal using the first pump light in the first coupled optical signal to obtain the third optical signal output by the N-core gain optical fiber.

[0232] S1607 converts the third optical signal into a fourth optical signal transmitted through the third N-core optical fiber.

[0233] Specifically, the second core-pitch converter receives the third signal output from the N-core gain fiber and converts the third optical signal into a fourth optical signal transmitted through the third N-core fiber.

[0234] In this configuration, the first N-core fiber and the third N-core fiber have the same core spacing, the second N-core fiber and the N-core gain fiber have the same core spacing, and the first N-core fiber and the second N-core fiber have different core spacings, where N is an integer greater than 1.

[0235] It should be noted that this N-core gain fiber can be a rare-earth-doped fiber, such as erbium-doped fiber, or other types of fiber. The principle of this doped optical signal can be simply understood as follows: when the signal light and pump light are simultaneously injected into the erbium fiber, the erbium ions are excited to a high energy level under the action of the pump light and quickly decay to a metastable energy level. When they return to the ground state under the action of the incident signal light, they emit photons corresponding to the signal light, thus amplifying the signal.

[0236] In one feasible implementation, the core spacing of the first N-core fiber is smaller than that of the second N-core fiber, while the core spacing of the N-core gain fiber is larger than that of the third N-core fiber. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter increases from small to large, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter decreases from large to large.

[0237] In this configuration, the first and third N-core fibers can be randomly coupled N-core fibers or other types of N-core fibers, while the second N-core fiber can be a weakly coupled N-core fiber or another type of N-core fiber. When the first and third N-core fibers are randomly coupled N-core fibers, the inter-core spacing of the randomly coupled N-core fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber can be a weakly coupled N-core fiber, and the inter-core spacing of the weakly coupled N-core fiber can be greater than 40 μm.

[0238] In one feasible implementation, the core spacing of the first N-core fiber is greater than that of the second N-core fiber, while the core spacing of the N-core gain fiber is less than that of the third N-core fiber. That is, the core spacing of the fibers connected to the input and output ends of the first core spacing converter decreases, and correspondingly, the core spacing of the fibers connected to the input and output ends of the second core spacing converter increases.

[0239] In this configuration, the first and third N-core fibers can be randomly coupled N-core fibers or other types of N-core fibers, while the second N-core fiber can be a randomly coupled N-core fiber with a smaller core pitch or another type of N-core fiber. When the first and third N-core fibers are randomly coupled N-core fibers, the core pitch range of these fibers can be 17-25 μm or other ranges. In this case, the second N-core fiber can be a multi-core fiber with a core pitch range of 8-16 μm.

[0240] The method for amplifying optical signals provided in this application embodiment can ensure that the optical layers of the core signal paths in multi-core optical fibers are consistent, thus preventing the accumulation of delay differences. This resolves many limitations imposed by delay difference accumulation, such as increased complexity in received signal processing, power consumption, switching delay, and maintenance. Furthermore, the use of a core-pumped approach allows for individual control of the amplification performance of each core, ensuring consistency in amplification performance between cores and improving practicality.

[0241] This application also provides an apparatus, including a processor and an interface. The processor can be used to perform the methods described in the above method embodiments.

[0242] It should be understood that the aforementioned processing device can be a chip. For example, the processing device can be a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a system-on-chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), or other integrated chips.

[0243] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware processor, or by a combination of hardware and software modules in the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0244] It should be noted that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuitry in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above methods.

[0245] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0246] According to the method provided in the embodiments of this application, this application also provides a computer program product, which includes: computer program code, which, when run on a computer, causes the computer to execute... Figures 15 to 16 The method of any one of the embodiments shown.

[0247] According to the method provided in the embodiments of this application, this application also provides a computer-readable medium storing program code, which, when run on a computer, causes the computer to perform... Figures 15 to 16 The method of any one of the embodiments shown.

[0248] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0249] The terms “component,” “module,” “system,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. As illustrated, applications running on computing devices and computing devices can both be components. One or more components may reside in a process and / or an execution thread, and components may be located on a single computer and / or distributed among two or more computers. Furthermore, these components can be executed from various computer-readable media on which various data structures are stored. Components can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system, and / or a network, such as the Internet interacting with other systems via signals).

[0250] Those skilled in the art will recognize that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0251] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0252] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0253] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0254] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0255] In the above embodiments, the functions of each functional unit can be implemented entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions (programs). When the computer program instructions (programs) are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks, SSDs), etc.

[0256] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0257] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An optical fiber amplifier, characterized in that, include: A first core-pitch converter is used to convert the first optical signal transmitted through the first N-core optical fiber into the second optical signal transmitted through the second N-core optical fiber. A gain module is used to amplify the second optical signal based on the first pump light to obtain a third optical signal; The second core-pitch converter is used to convert the third optical signal into a fourth optical signal for transmission through the third N-core optical fiber. Wherein, the first N-core optical fiber and the third N-core optical fiber have the same core spacing, and the first N-core optical fiber and the second N-core optical fiber have different core spacing, where N is an integer greater than 1.

2. The fiber optic amplifier according to claim 1, characterized in that, The gain module includes: The first module is used to couple the second optical signal with the first pump light to obtain a first coupled optical signal; An N-core gain fiber is used to amplify the second optical signal in the first coupled optical signal to obtain the third optical signal. The second N-core fiber has the same core spacing as the N-core gain fiber.

3. The fiber optic amplifier according to claim 1 or 2, characterized in that, The inter-core spacing of the first N-core optical fiber is smaller than the inter-core spacing of the second N-core optical fiber.

4. The fiber optic amplifier according to claim 3, characterized in that, The intercore spacing of the first N-core optical fiber ranges from 17 to 25. The intercore spacing of the second N-core optical fiber is greater than 40. .

5. The fiber optic amplifier according to claim 1 or 2, characterized in that, The inter-core spacing of the first N-core optical fiber is greater than the inter-core spacing of the second N-core optical fiber.

6. The fiber optic amplifier according to claim 5, characterized in that, The intercore spacing of the first N-core optical fiber ranges from 17 to 25. The intercore spacing of the second N-core optical fiber ranges from 8 to 16. .

7. The fiber optic amplifier according to claim 2, characterized in that, The first module includes: The first laser group includes N pump lasers for generating N second pump beams; A first pump light fan-in is used to couple the N second pump lights to generate the first pump light; A first combiner is used to couple the second optical signal with the first pump light to generate the first coupled optical signal.

8. The fiber optic amplifier according to claim 2, characterized in that, The first module includes: A first laser is used to generate the first pump light; A second combiner is used to couple the second optical signal with the first pump light to generate the first coupled optical signal.

9. A method for amplifying optical signals, characterized in that, include: The first optical signal transmitted through the first N-core optical fiber is converted into a second optical signal transmitted through the second N-core optical fiber; The second optical signal is amplified by the first pump light to obtain the third optical signal; The third optical signal is converted into a fourth optical signal for transmission through the third N-core optical fiber. Wherein, the first N-core optical fiber and the third N-core optical fiber have the same core spacing, and the first N-core optical fiber and the second N-core optical fiber have different core spacing, where N is an integer greater than 1.

10. The method according to claim 9, characterized in that, The third optical signal is obtained by amplifying the second optical signal based on the first pump light, including: The second optical signal is coupled to the first pump light to obtain a first coupled optical signal; The second optical signal in the first coupled optical signal is amplified using an N-core high-gain fiber to obtain the third optical signal. The second N-core fiber has the same core spacing as the N-core gain fiber.

11. The method according to claim 9 or 10, characterized in that, The inter-core spacing of the first N-core optical fiber is smaller than the inter-core spacing of the second N-core optical fiber.

12. The method according to claim 11, characterized in that, The intercore spacing of the first N-core optical fiber ranges from 17 to 25. The intercore spacing of the second N-core optical fiber is greater than 40. .

13. The method according to claim 9 or 10, characterized in that, The inter-core spacing of the first N-core optical fiber is greater than the inter-core spacing of the second N-core optical fiber.

14. The method according to claim 13, characterized in that, The intercore spacing of the first N-core optical fiber ranges from 17 to 25. The intercore spacing of the second N-core optical fiber ranges from 8 to 16. .

15. The method according to claim 10, characterized in that, The step of coupling the second optical signal with the first pump light to obtain a first coupled optical signal includes: Generate N channels of second pump light; The N-channel second pump light is coupled to generate the first pump light; The second optical signal is coupled to the first pump light to generate the first coupled optical signal.

16. The method according to claim 10, characterized in that, The step of coupling the second optical signal with the first pump light to obtain a first coupled optical signal includes: Generate the first pump light; The second optical signal is coupled to the first pump light to generate the first coupled optical signal. The N-core gain fiber includes a double-clad N-core gain fiber.

17. An optical fiber communication system, characterized in that, include: A multi-core transmission optical fiber, wherein the multi-core transmission optical fiber is used to transmit optical signals; An optical amplifier station, the optical amplifier station including an optical fiber amplifier as described in any one of claims 1-8, the optical fiber amplifier being used to amplify the optical signal.

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