Multi-core few-mode optical fiber multiplexer based on multi-plane light conversion and application method

Abstract

The invention relates to a multi-core few-mode optical fiber multiplexer based on multi-plane light conversion and an application method. The multiplexer comprises a laser light source 1, a single-mode optical fiber array 2, a collimator 3, a multi-plane light converter 4, a beam expander 5 and a multi-core few-mode optical fiber 6. The input end of the single-mode fiber array 2 is connected with the laser light source 1; the input end of the collimator 3 is connected with the output end of the single-mode fiber array 2; the multi-plane light converter 4 is used for receiving the collimated light beam, performing phase conversion and optical conversion, and outputting an output light field with specific intensity and phase distribution; the beam expander 5 is used for adjusting the diameter of the light beam processed by the planar light converter 4; and the input end of the multi-core few-mode optical fiber 6 is used for coupling an output light field of the beam expander 5.

Description

Technical Field

[0001] This application relates to the field of optical fiber communication technology, and in particular, to a multi-core few-mode fiber multiplexer based on multi-plane optical conversion and an application method thereof. Background Art

[0002] With the rapid development of communication technology, the transmission capacity of traditional single-mode optical fibers has approached its physical limit. Space-division multiplexing technology has become a key direction to break through the capacity bottleneck by using spatially orthogonal channels for parallel transmission. For example, multi-core optical fibers significantly improve capacity through multi-core independent transmission, while few-mode optical fibers achieve single-fiber multi-channel transmission through mode multiplexing. However, there are still significant challenges in multi-dimensional multiplexing and the design of efficient multiplexing / demultiplexing devices in the prior art.

[0003] Although the multi-core fiber connector technology is mature, its multiplexing scheme usually only targets a single spatial dimension and does not combine the mode dimension, resulting in limited capacity improvement; the mode multiplexing of few-mode optical fibers requires complex devices and has problems such as mode crosstalk, differential group delay, and mode-related loss, and relies on high-complexity MIMO algorithms for equalization, with poor compatibility with existing optical communication systems. Multi-core few-mode optical fibers can theoretically increase the capacity by dozens of times that of traditional single-mode optical fibers by combining the space-division and mode-division dimensions.

[0004] As an emerging optical technology, multi-plane optical conversion has the characteristics of low loss, efficient mode conversion, and high flexibility. It consists of multiple phase plates or spatial light modulators, and through continuous phase transformation and optical transformation, precise phase control is achieved.

[0005] In the patent with the patent number CN116203681A, a metasurface multi-core fiber fan-in / fan-out device is proposed, which includes a metasurface unit, an optical fiber array, a substrate, and a multi-core optical fiber. The metasurface unit is connected to the substrate, one side of the substrate is connected to the optical fiber array, and the other side of the substrate is connected to the multi-core optical fiber: the optical fiber array or the multi-core optical fiber emits light, and the light propagates through the metasurface unit to the multi-core optical fiber or the optical fiber array for coupling. In the patent with the patent number CN116224475A, a device for processing optical radiation is proposed, including: an optical input end for receiving an input light beam from a light source and for transmitting the input radiation in the device; an optical output end for emitting an output light beam with predetermined spatial parameters; an MPLC conversion device arranged between the optical input end and the optical output end and configured to spatially separate the input radiation into useful radiation and interference radiation in a separation plane, and the useful radiation is the target mode and is transmitted to the optical output end. The prior art can achieve space-division multiplexing of multi-core optical fibers or mode-division multiplexing of few-mode optical fibers through multi-plane optical conversion technology, but has not yet realized the combination of multi-plane optical conversion technology with space-division and mode-division multiplexing of multi-core few-mode optical fibers. Summary of the Invention

[0006] Based on this, it is necessary to provide a multi-core few-mode fiber multiplexer and application method based on multi-plane optical conversion for the technical problems existing in the background technology. The technical solution adopted by the present invention is as follows:

[0007] In the first aspect of the present invention, a multi-core few-mode fiber multiplexer based on multi-plane optical conversion is provided. The multiplexer includes a laser light source, a single-mode fiber array, a collimator, a multi-plane optical converter, a beam expander, and a multi-core few-mode fiber;

[0008] The input end of the single-mode fiber array is connected to the laser light source; the input end of the collimator is connected to the output end of the single-mode fiber array; the multi-plane optical converter is used to receive the collimated light beam and perform phase transformation and optical conversion, and output an output light field with a specific intensity and phase distribution; the beam expander is used to adjust the beam diameter of the light beam processed by the plane optical converter; the input end of the multi-core few-mode fiber is used to couple the output light field of the beam expander.

[0009] As a preferred solution, the single-mode fiber array is arranged in a two-dimensional array.

[0010] As a preferred solution, the collimator includes a microlens array, and each microlens corresponds to one fiber channel in the single-mode fiber array.

[0011] As a preferred solution, the multi-plane optical converter includes a phase plate and a mirror placed in parallel; the phase plate is used to perform phase transformation on the light beam, and the mirror is used to perform optical conversion on the light beam.

[0012] As a preferred solution, the multi-core few-mode fiber is configured with seven cores, and the multi-core few-mode fiber includes a first core, a second core, a third core, a fourth core, a fifth core, a sixth core, and a seventh core, where the number of mode types supported by each core is the same.

[0013] As a preferred solution, the multi-core few-mode fiber is a seven-core three-mode configuration, and each core supports three modes of LP01, LP11a, and LP11b.

[0014] As a preferred solution, the multi-core few-mode fiber is a seven-core six-mode fiber, and each core supports six modes of LP01, LP11a, LP11b, LP02, LP21a, and LP21b.

[0015] As a preferred solution, the number of fibers in the single-mode fiber array is three times the number of cores in the multi-core few-mode fiber.

[0016] As a preferred solution, the number of fibers in the single-mode fiber array is six times the number of cores in the multi-core few-mode fiber.

[0017] The second aspect of the present invention provides a method for applying a multi-core few-mode fiber multiplexer based on multi-plane optical conversion, including the following steps:

[0018] S1: Split and input the optical signal output by the laser light source through a single-mode fiber array, and only select a single single-mode fiber for light passing each time;

[0019] S2: Collimate the light beam output by the single-mode fiber through a collimator to form a parallel light beam;

[0020] S3: Input the collimated light beam into the multi-plane optical converter at a preset incident angle to form an optical field matching the target core and mode;

[0021] S4: Adjust the beam diameter of the optical field through a beam expander to adapt it to the core pitch and mode field distribution of the multi-core few-mode fiber;

[0022] S5: Couple the adjusted optical field into the specified core of the multi-core few-mode fiber, where the input serial number of the single-mode fiber array corresponds one-to-one with the core serial number and mode type of the multi-core few-mode fiber through a predefined mapping relationship.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The present invention adopts a space-division-mode-division multiplexing / demultiplexer of a multi-core few-mode fiber based on multi-plane optical conversion, replacing the traditional space-division-mode-division multiplexing / demultiplexer, and improving the multiplexing rate of the optical fiber communication system; the present invention designs the single-mode fiber array into a special two-dimensional arrangement, improving the mode purity and coupling efficiency. Description of the Drawings

[0025] Figure 1 Schematic structural diagram of a multi-core few-mode fiber multiplexer based on multi-plane optical conversion provided by this embodiment;

[0026] Figure 2 Schematic cross-sectional diagram of a multi-core few-mode fiber provided by this embodiment;

[0027] Figure 3 Schematic diagram of the mode of a multi-core few-mode fiber provided by this embodiment;

[0028] Figure 4 Schematic arrangement diagram of the single-mode fiber array corresponding to the seven-core three-mode fiber provided by this embodiment;

[0029] Figure 5 Schematic arrangement diagram of the single-mode fiber array corresponding to the seven-core six-mode fiber provided by this embodiment;

[0030] Figure 6An application method of a multi-core few-mode fiber multiplexer based on multi-plane optical conversion provided by this embodiment;

[0031] Description of reference numerals: 1. Laser light source; 2. Single-mode fiber array; 3. Collimator; 4. Multi-plane optical converter; 41. Phase plate; 42. Reflector; 5. Beam expander; 6. Multi-core few-mode fiber; 61. First core; 62. Second core; 63. Third core; 64. Fourth core; 65. Fifth core; 66. Sixth core; 67. Seventh core. Specific implementation manner

[0032] In order to make the objectives, technical solutions and advantages of this application clearer, the following further elaborates on this application in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0033] Embodiment 1

[0034] Please refer to Figure 1 , this embodiment provides a multi-core few-mode fiber multiplexer based on multi-plane optical conversion. The multiplexer includes a laser light source 1, a single-mode fiber array 2, a collimator 3, a multi-plane optical converter 4, a beam expander 5, and a multi-core few-mode fiber 6;

[0035] The input end of the single-mode fiber array 2 is connected to the laser light source 1; the input end of the collimator 3 is connected to the output end of the single-mode fiber array 2; the multi-plane optical converter 4 is used to receive the collimated light beam and perform phase transformation and optical conversion, and output an output light field with a specific intensity and phase distribution; the beam expander 5 is used to adjust the beam diameter of the light beam processed by the plane optical converter 4; the input end of the multi-core few-mode fiber 6 is used to couple the output light field of the beam expander 5.

[0036] In a specific embodiment, the single-mode fiber array 2 is arranged in a two-dimensional array.

[0037] In a specific embodiment, the collimator 3 includes a microlens array, and each microlens corresponds to a fiber channel in the single-mode fiber array 2.

[0038] In a specific embodiment, the multi-plane optical converter 4 includes a phase plate 41 and a reflector 42 placed in parallel; the phase plate 41 is used to perform phase transformation on the light beam, and the reflector 42 is used to perform optical conversion on the light beam.

[0039] In a specific embodiment, please refer to Figure 2, the multi-core few-mode fiber 6 is configured with seven cores, and the multi-core few-mode fiber includes a first core 61, a second core 62, a third core 63, a fourth core 64, a fifth core 65, a sixth core 66, and a seventh core 67, where the number of mode types supported by each core is the same.

[0040] In a specific embodiment, please refer to Figure 3 , the multi-core few-mode fiber 6 is configured with seven cores and three modes, and each core supports three modes: LP01, LP11a, and LP11b.

[0041] In a specific embodiment, the number of optical fibers in the single-mode fiber array 2 is three times the number of cores of the multi-core few-mode fiber 6.

[0042] Specifically, the two-dimensional arrangement adopted by the single-mode fiber array is as Figure 4 shown. The laser light source 1 is connected to the single-mode fiber array 2, and only a single single-mode fiber is optically conductive each time. Finally, the coupling of a specific mode optical field and a specific core is achieved at the output end. The mapping relationship between the input optical fiber numbers of the single-mode fiber array and the output optical fiber numbers of the seven-core three-mode fiber is shown in Table 1.

[0043] Table 1: Seven-core three-mode fiber

[0044] Single-mode fiber array serial number Core serial number, mode 01 61, LP01 02 61, LP11a 03 61, LP11b 04 62, LP01 05 62, LP11a 06 62, LP11b 07 63, LP01 08 63, LP11a 09 63, LP11b 10 64, LP01 11 64, LP11a 12 64, LP11b 13 65, LP01 14 65, LP11a 15 65, LP11b 16 66, LP01 17 66, LP11a 18 66, LP11b 19 67, LP01 20 67, LP11a 21 67, LP11b

[0045] Embodiment 2

[0046] Please refer to Figure 1 , this embodiment provides a multi-core few-mode fiber multiplexer based on multi-plane light conversion. The multiplexer includes a laser light source 1, a single-mode fiber array 2, a collimator 3, a multi-plane light converter 4, a beam expander 5, and a multi-core few-mode fiber 6;

[0047] The input end of the single-mode fiber array 2 is connected to the laser light source 1; the input end of the collimator 3 is connected to the output end of the single-mode fiber array 2; the multi-plane light converter 4 is used to receive the collimated light beam and perform phase transformation and optical conversion, and output an output light field with a specific intensity and phase distribution; the beam expander 5 is used to adjust the beam diameter of the light beam processed by the plane light converter 4; the input end of the multi-core few-mode fiber 6 is used to couple the output light field of the beam expander 5.

[0048] In a specific embodiment, the single-mode fiber array 2 is arranged in a two-dimensional array.

[0049] In a specific embodiment, the collimator 3 includes a microlens array, and each microlens corresponds to an optical fiber channel in the single-mode fiber array 2.

[0050] In a specific embodiment, the multi-plane optical converter 4 includes a phase plate 41 and a mirror 42 arranged in parallel; the phase plate 41 is used for performing phase transformation on the light beam, and the mirror 42 is used for performing optical conversion on the light beam.

[0051] In a specific embodiment, please refer to Figure 2 , the multi-core few-mode fiber 6 is configured with seven cores, and the multi-core few-mode fiber includes a first core 61, a second core 62, a third core 63, a fourth core 64, a fifth core 65, a sixth core 66, and a seventh core 67, where the number of mode types supported by each core is the same.

[0052] In a specific embodiment, please refer to Figure 3 , the multi-core few-mode fiber 6 is a seven-core six-mode fiber, and each core supports six modes: LP01, LP11a, LP11b, LP02, LP21a, and LP21b.

[0053] In a specific embodiment, the number of optical fibers in the single-mode fiber array 2 is six times the number of cores of the multi-core few-mode fiber 6.

[0054] Specifically, the two-dimensional arrangement adopted by the single-mode fiber array 2 is as Figure 5 shown. The laser light source 1 is connected to the single-mode fiber array 2, and only a single single-mode fiber is optically conductive each time. Finally, the coupling of a specific mode optical field and a specific core is achieved at the output end. The mapping relationship between the input optical numbers of the single-mode fiber array and the output optical numbers of the seven-core six-mode fiber is shown in Table 2.

[0055] Table 2: Seven-core six-mode fiber

[0056] Single-mode fiber array serial number Core serial number, mode 01 61, LP01 02 61, LP11a 03 61, LP11b 04 61, LP02 05 61, LP21a 06 61, LP21b 07 62, LP01 08 62, LP11a 09 62, LP11b 10 62, LP02 11 62, LP21a 12 62, LP21b 13 63, LP01 14 63, LP11a 15 63, LP11b 16 63, LP02 17 63, LP21a 18 63, LP21b 19 64, LP01 20 64, LP11a 21 64, LP11b 22 64, LP02 23 64, LP21a 24 64, LP21b 25 65, LP01 26 65, LP11a 27 65, LP11b 28 65, LP02 29 65, LP21a 30 65, LP21b 31 66, LP01 32 66, LP11a 33 66, LP11b 34 66, LP02 35 66, LP21a 36 66, LP21b 37 67, LP01 38 67, LP11a 39 67, LP11b 40 67, LP02 41 67, LP21a 42 67, LP21b

[0057] Embodiment 3

[0058] Please refer to Figure 6 , this embodiment provides a method for applying a multi-core few-mode fiber multiplexer based on multi-plane optical conversion, including the following steps:

[0059] S1: Split and input the optical signal output by the laser light source 1 through the single-mode fiber array 2, and only select a single single-mode fiber for optical conduction each time;

[0060] S2: Collimate the light beam output from the single-mode fiber through the collimator 3 to form a parallel light beam;

[0061] S3: Input the collimated light beam into the multi-plane optical converter 4 at a preset incident angle to form an optical field matching the target core and mode;

[0062] S4: Adjust the beam diameter of the optical field through the beam expander 5 to make it adapt to the core pitch and mode field distribution of the multi-core few-mode fiber 6;

[0063] S5: Couple the adjusted optical field into the specified core of the multi-core few-mode fiber 6, where the input sequence number of the single-mode fiber array corresponds one-to-one with the core sequence number and mode type of the multi-core few-mode fiber through a predefined mapping relationship.

[0064] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A multi-core few-mode fiber multiplexer based on multi-plane light conversion, characterized in that The multiplexer includes a laser light source (1), a single-mode fiber array (2), a collimator (3), a multi-planar light converter (4), a beam expander (5), and a multi-core few-mode fiber (6); The input end of the single-mode fiber array (2) is connected to the laser light source (1); the input end of the collimator (3) is connected to the output end of the single-mode fiber array (2); the multi-planar light converter (4) is configured to receive the collimated light beam, perform phase transformation and optical conversion, and output an output optical field with a specific intensity and phase distribution; the beam expander (5) is used to adjust the beam diameter of the light beam processed by the planar light converter (4); the input end of the multi-core few-mode fiber (6) is used to couple the output optical field of the beam expander (5).

2. The multi-core few-mode fiber multiplexer based on multi-plane optical conversion according to claim 1, characterized in that The single-mode fiber array (2) is arranged in a two-dimensional array.

3. The multi-core few-mode fiber multiplexer based on multi-plane optical conversion according to claim 1, wherein The collimator (3) includes a microlens array, and each microlens corresponds to one fiber channel in the single-mode fiber array (2).

4. The multi-core few-mode fiber multiplexer based on multi-plane optical conversion according to claim 1, wherein The multi-planar light converter (4) includes a phase plate (41) and a mirror (42) arranged in parallel; the phase plate (41) is used to perform phase transformation on the light beam, and the mirror (42) is used to perform optical conversion on the light beam.

5. A multi-core few-mode fiber multiplexer based on multi-plane optical conversion according to claim 1, characterized in that The multi-core few-mode fiber (6) has a seven-core configuration, and the multi-core few-mode fiber includes a first core (61), a second core (62), a third core (63), a fourth core (64), a fifth core (65), a sixth core (66), and a seventh core (67), where the number of mode types supported by each core is the same.

6. The multi-core few-mode fiber multiplexer based on multi-plane optical conversion according to claim 5, wherein The multi-core few-mode fiber (6) has a seven-core three-mode configuration, and each core supports three modes: LP01, LP11a, and LP11b.

7. A multi-core few-mode fiber multiplexer based on multi-plane optical conversion according to claim 5, characterized in that, The multi-core few-mode fiber (6) is a seven-core six-mode fiber, and each core supports six modes: LP01, LP11a, LP11b, LP02, LP21a, and LP21b.

8. The multi-core few-mode fiber multiplexer based on multi-plane optical conversion according to claim 6, wherein The number of optical fibers in the single-mode fiber array (2) is three times the number of cores in the multi-core few-mode fiber (6).

9. The multi-core few-mode fiber multiplexer based on multi-plane optical conversion according to claim 7, wherein, The number of optical fibers in the single-mode fiber array (2) is six times the number of cores in the multi-core few-mode fiber (6).

10. A method for applying a multi-core few-mode fiber multiplexer based on multi-plane light conversion, characterized in that, It includes the following steps: S1: The optical signal output by the laser light source (1) is split and input through the single-mode fiber array (2), and only a single single-mode fiber is selected for light transmission each time; S2: The light beam output from the single-mode fiber is collimated by the collimator (3) to form a parallel light beam; S3: The collimated light beam is input into the multi-planar light converter (4) at a preset incident angle to form an optical field matching the target core and mode; S4: The beam diameter of the optical field is adjusted by the beam expander (5) to adapt it to the core pitch and mode field distribution of the multi-core few-mode fiber (6); S5: The adjusted optical field is coupled into the specified core of the multi-core few-mode fiber (6), where the input serial number of the single-mode fiber array corresponds one-to-one with the core serial number and mode type of the multi-core few-mode fiber through a predefined mapping relationship.

Images