Multi-wavelength dispersion compensation device and system based on fiber bragg grating

Abstract

The invention provides a multi-wavelength dispersion compensation device and system based on a fiber bragg grating, and relates to the field of multi-wavelength dispersion compensation, and the device comprises an input optical unit with a plurality of optical ports, a polarization beam splitting rotation unit, a polarization-maintaining transmission unit arranged on a common optical path, the fiber bragg grating, and an isolation output unit. According to the invention, multi-wavelength dispersion compensation can be realized at the same time, the difficulty of an assembly technology is reduced, multiple coupling is reduced, the loss is optimized, and the module is miniaturized; multiple wavelengths are realized in one assembly at the same time, and are assembled into the module in a free space form; multiple ports are located on the same side, multi-channel and multi-wavelength dispersion compensation is achieved, and placement and design of other elements in the module are facilitated; multi-channel parallel arrangement can be realized, and small-size and high-precision multi-wavelength dispersion compensation is realized; the light path insertion loss is low, the light emitting angle is small, the system performance can be improved, and module assembly and production are facilitated; the packaging form can be adjusted according to actual application, and different application scenes in the market are met.

Description

Technical Field

[0001] This invention relates to the field of multi-wavelength dispersion compensation technology, and in particular to a multi-wavelength dispersion compensation device and system based on fiber Bragg gratings. Background Technology

[0002] In high-speed optical communication systems (such as 100G, 400G, 1.6T and higher speeds), especially in long-distance or metropolitan area backbone transmissions, dispersion is one of the key factors limiting transmission distance and signal quality. Dispersion causes optical pulses to broaden as they propagate in optical fibers, leading to inter-symbol interference and thus reducing the system's signal-to-noise ratio and bit error rate performance. Therefore, effective dispersion compensation techniques are essential for achieving high-speed, high-capacity optical communication.

[0003] Currently, common dispersion compensation schemes mainly include dispersion-compensating fibers and dispersion compensators based on fiber gratings. Among them, Dispersion-compensating fiber compensates for the positive dispersion of the transmission fiber by cascading a special fiber with negative dispersion characteristics in the link. This approach is technically mature, but it suffers from problems such as high insertion loss, strong nonlinear effects, and large and bulky module size, making it difficult to meet the urgent needs of modern optical modules (especially pluggable optical modules) for miniaturization, low power consumption, and integration.

[0004] Fiber Bragg grating dispersion compensators (FBG-DCMs) utilize the wavelength selectivity and dispersion characteristics of fiber Bragg gratings to reflect optical signals of specific wavelengths and introduce a controllable group delay, thereby achieving precise dispersion compensation. Compared to DCFs, FBG-DCMs offer advantages such as lower insertion loss, smaller nonlinear effects, and higher compensation accuracy. However, traditional fiber Bragg grating-based dispersion compensation modules are typically constructed using discrete component combinations. For example, multiple circulators or optical switches are used to separate the input / output optical paths and connect to the fiber Bragg grating to achieve single-channel or multi-channel operation.

[0005] This traditional discrete structure has the following inherent drawbacks: Large size and complex structure: Each channel requires independent circulators and other components, making it difficult to reduce the size of the entire module and failing to meet the extremely limited physical space requirements inside high-speed optical modules (such as QSFP-DD, OSFP).

[0006] High cost: The use of multiple precision optical components (such as circulators, isolators, and collimators), as well as complex alignment and packaging processes, significantly increases manufacturing costs.

[0007] Reliability challenges: The large number of discrete components and connection points (such as fiber optic splices and adhesive bonding points) reduces the overall mechanical stability and long-term reliability of the module.

[0008] Low integration: It is difficult to achieve efficient multiplexing and unified management of multiple wavelength channels on the same compact physical platform, which limits its high-density application in wavelength division multiplexing systems.

[0009] As data center interconnects and telecommunications networks evolve towards 800G, 1.6T, and even 3.2T speeds, optical modules need to handle multiple wavelength channels, placing higher demands on dispersion compensation devices: miniaturization, high integration, low cost, and high reliability.

[0010] Therefore, there is an urgent need for an innovative dispersion compensation device structure that can highly integrate the input, polarization control, grating coupling and output functions of multiple wavelength channels onto a miniaturized and stable platform, thereby meeting the packaging requirements of next-generation high-speed optical modules. Summary of the Invention

[0011] To achieve the above-mentioned objectives and other advantages of the present invention, a first objective of the present invention is to provide a multi-wavelength dispersion compensation device based on a fiber Bragg grating, comprising: An input optical unit with multiple optical ports is used to receive linearly polarized light of different wavelengths from different ports; A polarization beam splitting and rotating unit is used to guide linearly polarized light from the input optical unit to a common optical path and rotate the polarization direction of the linearly polarized light returning from the common optical path by 90 degrees. The polarization-maintaining transmission unit disposed on the common optical path is used to maintain the polarization state of light and transmit it to the fiber grating. A fiber grating, connected to the polarization-maintaining transmission unit, is used to reflect light from at least one optical port to achieve dispersion compensation and to transmit light from other optical ports. An isolation output unit is used to receive reflected light from the fiber grating reflected by the polarization beam splitter rotation unit, isolate it, and then couple it out. The input optical unit, the polarization beam splitting and rotating unit, and the isolation output unit are fixedly connected by an optical adhesive layer and integrated on the same optical substrate.

[0012] Furthermore, the input optical unit includes: An optical glass block, with four optical ports on one side; A bandpass filter film is disposed at each optical port of the optical glass block; A reflective film layer disposed inside the optical glass block is used to guide light that has entered from the optical port and been filtered by the corresponding bandpass filter to the common exit surface. The common emission surface is located on the optical glass block, and an anti-reflection coating is disposed thereon.

[0013] Furthermore, for the Nth optical port, the incident light is reflected 4-N times in sequence through the Nth bandpass filter and the reflective film layer inside the optical glass block before reaching the common exit surface, where N is a positive integer not greater than the total number of optical ports.

[0014] Furthermore, the four optical ports of the input optical unit are respectively the first port, the second port, the third port and the fourth port; the bandpass filter films at each port are respectively the first bandpass filter film, the second bandpass filter film, the third bandpass filter film and the fourth bandpass filter film; Light from the first port passes through the first bandpass filter film in sequence, and is reflected three times by the reflective film layer inside the optical glass block before reaching the common emission surface; The light from the second port passes through the second bandpass filter film in sequence, and is reflected twice by the reflective film layer inside the optical glass block before reaching the common emission surface; Light from the third port passes through the third bandpass filter in sequence, and is reflected once by the reflective film inside the optical glass block before reaching the common exit surface; Light from the fourth port passes through the fourth bandpass filter and then directly reaches the common emission surface.

[0015] Furthermore, the polarization beam splitting rotation unit includes: A polarizing beam splitter is used to transmit linearly polarized light having a first polarization direction and reflect linearly polarized light having a second polarization direction orthogonal to the first polarization direction. A Faraday rotator is disposed in the transmission light path of the polarizing beam splitter and is used to rotate the polarization direction of the passing linearly polarized light by 45 degrees.

[0016] Furthermore, the polarization-maintaining transmission unit is a polarization-maintaining collimator, whose input end is aligned with the optical path of the Faraday rotator, and whose output end is connected to the fiber grating through a polarization-maintaining optical fiber.

[0017] Furthermore, the linearly polarized light from the input optical unit, having a first polarization direction, passes sequentially through the polarization beam splitter, is rotated 45 degrees by the Faraday rotator, and is then polarized by the polarization-maintaining collimator and transmitted to the fiber grating. The light reflected back by the fiber grating passes through the polarization-maintaining collimator again, and is then rotated by the Faraday rotator by 45 degrees, so that its polarization direction becomes a second polarization direction orthogonal to the first polarization direction. When light with the second polarization direction returns to the polarizing beam splitter, it is reflected by it and thus guided to the isolation output unit.

[0018] Furthermore, the isolation output unit includes an isolator and an output collimator arranged in sequence. The isolator allows light from the polarization beam splitting rotation unit to pass through the output collimator and suppresses backlight.

[0019] Furthermore, the fiber grating is configured to reflect light from the first port and the second port to achieve dispersion compensation; and to transmit light from the third port and the fourth port.

[0020] A second objective of the present invention is to provide a multi-wavelength dispersion compensation system, comprising at least two of the above-mentioned fiber Bragg grating-based multi-wavelength dispersion compensation devices, wherein the at least two devices are arranged in parallel or cascaded to achieve dispersion compensation for more wavelength channels.

[0021] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a multi-wavelength dispersion compensation device and system based on fiber Bragg gratings, which can simultaneously perform dispersion compensation on multiple wavelengths and multiple channels, reducing assembly technical difficulty, reducing multiple couplings, optimizing loss, and achieving module miniaturization. Multiple wavelengths are implemented in a single component and assembled into the module in a free-space manner. All ports are located on the same side, realizing multi-channel, multi-wavelength dispersion compensation, which facilitates the placement and design of other components inside the module. The product can be arranged in parallel with multiple channels to achieve small size and high-precision multi-wavelength dispersion compensation. The optical path has low insertion loss and a small output angle, which is beneficial to improving system performance and facilitates module assembly and production. The packaging form can be adjusted according to actual applications to meet different application scenarios in the market.

[0022] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a structural diagram of a multi-wavelength dispersion compensation device based on a fiber Bragg grating; Figure 2 This is a schematic diagram of a multi-wavelength dispersion compensation system.

[0024] In the figure: 101, first bandpass filter film; 102, second bandpass filter film; 103, third bandpass filter film; 104, fourth bandpass filter film; 105, optical glass block; 106, polarization beam splitter prism; 107, Faraday rotator; 108, polarization-maintaining collimator; 109, fiber optic grating; 110, isolator; 111, output collimator. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the accompanying drawings, shapes and dimensions may be enlarged for clarity, and the same reference numerals will be used in all figures to indicate the same or similar parts.

[0027] In the following description, terms such as center, thickness, height, length, front, back, rear, left, right, top, bottom, upper, and lower are defined relative to the structure shown in the accompanying drawings. In particular, "height" corresponds to the dimension from top to bottom, "width" corresponds to the dimension from left to right, and "depth" corresponds to the dimension from front to back. These are relative concepts and may vary depending on their location and usage. Therefore, these or other orientations should not be interpreted as restrictive terms.

[0028] Terms involving attachment, connection, etc. (e.g., “connection” and “attachment”) refer to the relationship in which these structures are directly or indirectly fixed or attached to each other through an intermediate structure, as well as movable or rigid attachments or relationships, unless otherwise explicitly stated.

[0029] Example 1 A multi-wavelength dispersion compensation device based on fiber Bragg grating, such as Figure 1 As shown, it includes: An input optical unit with multiple optical ports is used to receive linearly polarized light with different specified wavelengths from different ports; A polarization beam splitting and rotating unit is used to guide linearly polarized light from the input optical unit to a common optical path and rotate the polarization direction of the linearly polarized light returning from the common optical path by 90 degrees. The polarization-maintaining transmission unit disposed on the common optical path is used to maintain the polarization state of light and transmit it to the fiber grating. A fiber grating, connected to the polarization-maintaining transmission unit, is used to reflect light of a first wavelength specified from at least one optical port to achieve dispersion compensation, and to transmit light of a second wavelength specified from other optical ports. An isolation output unit is used to receive reflected light from the fiber grating reflected by the polarization beam splitter rotation unit, isolate it, and then couple it out. The input optical unit, the polarization beam splitting and rotating unit, and the isolation output unit are fixedly connected by an optical adhesive layer and integrated on the same optical substrate.

[0030] In some embodiments, a highly integrated optical design enables efficient and stable merging and output of multiple optical paths, providing a compact and reliable solution for multispectral systems and optical communication systems. Specifically, the input optical unit includes: An optical glass block (105) has four optical ports on one of its sides; A bandpass filter film is disposed at each optical port of the optical glass block; A reflective film layer disposed inside the optical glass block is used to guide light that has entered from the optical port and been filtered by the corresponding bandpass filter to the common exit surface. The common emission surface is located on the optical glass block, and an anti-reflection coating is disposed thereon.

[0031] For the Nth optical port, the incident light is reflected 4-N times in sequence through the Nth bandpass filter and the reflective film inside the optical glass block before reaching the common exit surface, where N is a positive integer not greater than the total number of optical ports.

[0032] In some embodiments, time-domain or phase management of optical signals from different channels is achieved through precisely designed physical optical path differences, ensuring efficient signal combining and isolation. Specifically, the four optical ports of the input optical unit are a first port (port 1), a second port (port 2), a third port (port 3), and a fourth port (port 4); the bandpass filter films at each port are a first bandpass filter film (101), a second bandpass filter film (102), a third bandpass filter film (103), and a fourth bandpass filter film (104), respectively. Light of a specified wavelength from the first port passes through the first bandpass filter in sequence, and is reflected three times by the reflective film layer inside the optical glass block before reaching the common emission surface. Light of a specified wavelength from the second port passes sequentially through the second bandpass filter film and is reflected twice by the reflective film layer inside the optical glass block before reaching the common emission surface; Light of a specified wavelength from the third port passes sequentially through the third bandpass filter and is reflected once by the reflective film inside the optical glass block before reaching the common exit surface. Light of a specified wavelength from the fourth port passes through the fourth bandpass filter and directly reaches the common emission surface.

[0033] In some embodiments, by combining the reciprocal beam-splitting function of a polarizing beam-splitting prism with the non-reciprocal rotation function of a Faraday rotator, the system gains the crucial ability to control the directionality of light propagation. Specifically, the polarizing beam-splitting rotation unit includes: A polarizing beam splitter prism (106) is used to transmit linearly polarized light having a first polarization direction and reflect linearly polarized light having a second polarization direction orthogonal to the first polarization direction. A Faraday rotator (107) is disposed on the transmission light path of the polarizing beam splitter and is used to rotate the polarization direction of the passing linearly polarized light by 45 degrees.

[0034] In some embodiments, a deterministic polarization state transmission link is established and maintained between the free-space optical path and the fiber optic device, thereby ensuring the final realization of the entire system function and performance stability. Specifically, the polarization-maintaining transmission unit is a polarization-maintaining collimator (108), whose input end is aligned with the optical path of the Faraday rotator, and whose output end is connected to the fiber grating (109) through a polarization-maintaining fiber.

[0035] In some embodiments, to achieve multi-wavelength signal input, a complete, non-reciprocal optical path function is provided, with unidirectional filtering / reflection through a fiber optic grating and directional isolation output. Specifically, linearly polarized light with a first polarization direction from the input optical unit passes sequentially through the polarization beam splitter, is rotated 45 degrees by the Faraday rotator, has its polarization state maintained by the polarization-maintaining collimator, and is transmitted to the fiber optic grating. The light reflected back by the fiber grating passes through the polarization-maintaining collimator again, and is then rotated by the Faraday rotator by 45 degrees, so that its polarization direction becomes a second polarization direction orthogonal to the first polarization direction. When light with the second polarization direction returns to the polarizing beam splitter, it is reflected by it and thus guided to the isolation output unit.

[0036] In some embodiments, to ensure that the processed signal light is output purely and stably, and to absolutely prevent any external light signal from backtracking into the system core, thereby achieving the ultimate unidirectionality and stability of the system, the isolation output unit specifically includes an isolator (110) and an output collimator (111) arranged sequentially. The isolator allows light from the polarization beam splitting rotation unit toward the output collimator to pass through, while suppressing backlight.

[0037] In some embodiments, to make the device a four-channel dual-function optical processing core, it can simultaneously perform dispersion compensation (reflection processing) on ​​two light sources and transmit the other two light sources, achieving parallel signal processing and routing within a compact physical unit. Specifically, the fiber grating is configured to reflect light of a specified wavelength from the first and second ports to achieve dispersion compensation; and to transmit light of a specified wavelength from the third and fourth ports.

[0038] In summary, different wavelengths of polarized light are input to ports 1, 2, 3, and 4. Ports 1 and 2 undergo dispersion compensation through fiber optic gratings, and are combined with ports 2 and 3. After being protected by an isolator, the light is coupled into a collimator to achieve dispersion compensation for multi-wavelength light paths.

[0039] Grating fiber can simultaneously achieve dispersion compensation in two different port bands, enabling smaller, multi-level, and multi-channel compensation, making the module more compact and miniaturized.

[0040] Continue to refer to Figure 1 Port 1 optical path: When P-polarized light of a specified wavelength is transmitted from right to left through port 1, the P-polarized light is incident on the first bandpass filter film (101). After the film filters this wavelength, the light passes through the first bandpass filter film (101) to the right side of the optical glass block (105), and then is incident on the left side of the optical glass block (105) and reflected by the reflective film to the left side of the second bandpass filter film (102). It is then totally reflected by the total internal reflection film to the left side of the optical glass block (105) and reflected by the third bandpass filter film (102). 03) On the left, the light is reflected to the left side of the optical glass block (105). The light is reflected to the left side of the fourth bandpass filter film (104). The light of the specified wavelength is reflected to the left side of the antireflection film of the optical glass block (105). After passing through the polarization beam splitter (106), under the action of the transmitted P light and reflected S light in the dielectric beam splitter film of the polarization beam splitter, the P-polarized light passes through the first dielectric beam splitter film layer of the polarization beam splitter to the Faraday rotator (107). The polarized P light is rotated by 45 degrees and is still polarized light. Polarized light maintains its polarization state after passing through the polarization-maintaining collimator (108). It then passes through the polarization-maintaining fiber to the fiber grating (109). The fiber grating (109) provides dispersion compensation for a specific wavelength at port 1. This wavelength of light is reflected back to the polarization-maintaining collimator (108) by the fiber grating. After passing through the Faraday rotator (107), the polarized light is rotated by 45 degrees again. This beam is S-polarized light. When incident on the dielectric beam-splitting film of the polarization beam-splitting prism (106), the S-polarized light is reflected to the second dielectric beam-splitting film layer of the polarization beam-splitting prism (106), and similarly reflected to the isolator (110). The isolator... Figure 1From right to left, the light passes through the isolator and enters the collimator (111) and is transmitted out in the form of optical fiber.

[0041] Continue to refer to Figure 1 Port 2 optical path: When P-polarized light of a specified wavelength is transmitted from right to left through port 2, the P-polarized light is incident on the second bandpass filter film (102). After the film filters the light of this wavelength, the light passes through the second bandpass filter film (102) to the right side of the optical glass block (105), and is incident on the left side of the optical glass block (105). It is reflected by the reflective film layer to the left side of the third bandpass filter film (103), and is totally reflected by the total reflection film layer to the left side of the optical glass block (105). It is reflected by the total reflection film layer to the left side of the fourth bandpass filter film (104). The light of the specified wavelength is reflected to the antireflection film position on the left side of the optical glass block (105). After passing through the polarization beam splitter prism (106), under the action of the transmitted P light and reflected S light of the dielectric beam splitter film, the P-polarized light passes through the first dielectric beam splitter film layer of the polarization beam splitter prism (106) to the Faraday rotator (107). The polarized P light is rotated by 45 degrees and is still polarized light. Polarized light, after passing through the polarization-maintaining collimator (108), can maintain its polarization state. It then passes through the polarization-maintaining fiber to the fiber grating (109). The fiber grating (109) provides dispersion compensation for a specific wavelength at port 2. This wavelength of light is reflected back to the polarization-maintaining collimator (108) by the fiber grating. Passing again through the Faraday rotator (107), the polarized light is rotated by 45 degrees. This beam is S-polarized light. When incident on the dielectric beam-splitting layer of the polarization beam-splitting prism (106), the S-polarized light is reflected to the second dielectric beam-splitting layer of the polarization beam-splitting prism (106), and similarly reflected to the isolator (110). The isolator... Figure 1 From right to left, the light passes through the isolator and enters the output collimator (111) and is transmitted out in the form of optical fiber.

[0042] Continue to refer to Figure 1Port 3 optical path: When P-polarized light of a specified wavelength is transmitted from right to left through port 3, the P-polarized light is incident on the third bandpass filter film (103). The light passes through the filter and passes through the third bandpass filter film (103) to the right side of the optical glass block (105). It is incident on the left side of the optical glass block (105) and reflected by the reflective film layer to the left side of the fourth bandpass filter film (104). The light of the specified wavelength is reflected to the left side of the antireflective film position of the optical glass block (105). After passing through the polarization beam splitter prism (106), under the action of the transmitted P light and reflected S light of the dielectric beam splitter film, the P-polarized light passes through the first dielectric beam splitter film layer of the polarization beam splitter prism to the Faraday rotator (107). The polarized P light is rotated by 45 degrees and is still polarized light. Polarized light can maintain its polarization state after passing through the polarization-maintaining collimator (108) and then through the polarization-maintaining fiber to the fiber grating (109). The fiber grating (109) does not produce dispersion compensation for a specific wavelength at port 3. When this wavelength passes through the fiber grating (109), it is transmitted through the fiber and then exits. Light of different wavelengths passes through the fiber grating (109) for dispersion compensation.

[0043] Continue to refer to Figure 1 Port 4 optical path: When P-polarized light of a specified wavelength is transmitted from right to left through port 4, the P-polarized light is incident on the fourth bandpass filter film (104). After the film filters the light of this band, the light of the specified wavelength is reflected to the anti-reflection film position on the left side of the optical glass block (105). After passing through the polarization beam splitter prism (106), under the action of the transmitted P light and reflected S light in the dielectric beam splitter film, the P light passes through the first dielectric beam splitter film layer of the polarization beam splitter prism to the Faraday rotator (107). The polarized P light is rotated by 45 degrees and is still polarized. The polarized light passes through the polarization-maintaining collimator (108) to maintain its polarization state. It passes through the polarization-maintaining fiber to the fiber grating (109). The fiber grating (109) does not produce dispersion compensation for a specific wavelength of port 3. When this wavelength passes through the fiber grating (109), it is transmitted through the fiber and exits. Light of different wavelengths passes through the fiber grating (109) for dispersion compensation.

[0044] In this embodiment, the first bandpass filter (101), the second bandpass filter (102), the third bandpass filter (103), the fourth bandpass filter (104), the optical glass block (105), the polarization beam splitter prism (106), the Faraday rotator (107), the polarization-maintaining collimator (108), the fiber grating (109), the isolator (110), and the output collimator (111) are combined into a structural component. The components are bonded together with ultraviolet adhesive, making assembly convenient and the structure simple. The overall structure can be used as a single-fiber multidirectional structure in 1.6T, 3.2T, and other high-speed optical modules. It can also be packaged into a box structure for fiber input and output to be spliced ​​with other module structures. That is, this product can be arranged in parallel with multiple channels to achieve small size, high precision multi-wavelength dispersion compensation.

[0045] This invention provides a multi-wavelength dispersion compensation device based on fiber Bragg gratings, applicable to scenarios requiring multi-wavelength dispersion compensation such as data centers and communications. It enables simultaneous dispersion compensation across multiple wavelengths and channels, reducing assembly complexity, minimizing coupling, optimizing losses, and achieving module miniaturization. Multiple wavelengths are implemented within a single component, assembled into the module in a free-space configuration. Multiple ports are located on the same side, facilitating multi-channel, multi-wavelength dispersion compensation and simplifying the placement and design of other components within the module. The product can be arranged in parallel across multiple channels, achieving small-size, high-precision multi-wavelength dispersion compensation. Low optical path insertion loss and a small output angle improve system performance and facilitate module assembly and production. The packaging can be adjusted according to actual applications to meet different market demands.

[0046] Example 2 A multi-wavelength dispersion compensation system, such as Figure 2 As shown, it includes at least two of the above-mentioned fiber Bragg grating-based multi-wavelength dispersion compensation devices, with the at least two devices arranged in parallel or cascaded to achieve dispersion compensation for more wavelength channels.

[0047] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A multi-wavelength dispersion compensation device based on fiber Bragg gratings, characterized in that, include: An input optical unit with multiple optical ports is used to receive linearly polarized light of different wavelengths from different ports; A polarization beam splitting and rotating unit is used to guide linearly polarized light from the input optical unit to a common optical path and rotate the polarization direction of the linearly polarized light returning from the common optical path by 90 degrees. The polarization-maintaining transmission unit disposed on the common optical path is used to maintain the polarization state of light and transmit it to the fiber grating. A fiber grating, connected to the polarization-maintaining transmission unit, is used to reflect light from at least one optical port to achieve dispersion compensation and to transmit light from other optical ports. An isolation output unit is used to receive reflected light from the fiber grating reflected by the polarization beam splitter rotation unit, isolate it, and then couple it out. The input optical unit, the polarization beam splitting and rotating unit, and the isolation output unit are fixedly connected by an optical adhesive layer and integrated on the same optical substrate.

2. The multi-wavelength dispersion compensation device based on fiber Bragg grating as described in claim 1, characterized in that, The input optical unit includes: An optical glass block, with four optical ports on one side; A bandpass filter film is disposed at each optical port of the optical glass block; A reflective film layer disposed inside the optical glass block is used to guide light that has entered from the optical port and been filtered by the corresponding bandpass filter to the common exit surface. The common emission surface is located on the optical glass block, and an anti-reflection coating is disposed thereon.

3. The multi-wavelength dispersion compensation device based on fiber Bragg grating as described in claim 2, characterized in that, For the Nth optical port, the incident light is reflected 4-N times in sequence through the Nth bandpass filter and the reflective film inside the optical glass block before reaching the common exit surface, where N is a positive integer not greater than the total number of optical ports.

4. The multi-wavelength dispersion compensation device based on fiber Bragg grating as described in claim 3, characterized in that, The four optical ports of the input optical unit are the first port, the second port, the third port, and the fourth port, respectively; the bandpass filter films at each port are the first bandpass filter film, the second bandpass filter film, the third bandpass filter film, and the fourth bandpass filter film, respectively. Light from the first port passes through the first bandpass filter film in sequence, and is reflected three times by the reflective film layer inside the optical glass block before reaching the common emission surface; The light from the second port passes through the second bandpass filter film in sequence, and is reflected twice by the reflective film layer inside the optical glass block before reaching the common emission surface; Light from the third port passes through the third bandpass filter in sequence, and is reflected once by the reflective film inside the optical glass block before reaching the common exit surface; Light from the fourth port passes through the fourth bandpass filter and then directly reaches the common emission surface.

5. The multi-wavelength dispersion compensation device based on fiber Bragg grating as described in claim 1, characterized in that, The polarization beam splitting rotation unit includes: A polarizing beam splitter is used to transmit linearly polarized light having a first polarization direction and reflect linearly polarized light having a second polarization direction orthogonal to the first polarization direction. A Faraday rotator is disposed in the transmission light path of the polarizing beam splitter and is used to rotate the polarization direction of the passing linearly polarized light by 45 degrees.

6. The multi-wavelength dispersion compensation device based on fiber Bragg grating as described in claim 5, characterized in that, The polarization-maintaining transmission unit is a polarization-maintaining collimator, whose input end is aligned with the optical path of the Faraday rotator, and whose output end is connected to the fiber grating through a polarization-maintaining optical fiber.

7. A multi-wavelength dispersion compensation device based on a fiber Bragg grating as described in claim 6, characterized in that, Linearly polarized light with a first polarization direction from the input optical unit passes through the polarization beam splitter in sequence, is rotated 45 degrees by the Faraday rotator, and is then polarized by the polarization-maintaining collimator and transmitted to the fiber grating. The light reflected back by the fiber grating passes through the polarization-maintaining collimator again, and is then rotated by the Faraday rotator by 45 degrees, so that its polarization direction becomes a second polarization direction orthogonal to the first polarization direction. When light with the second polarization direction returns to the polarizing beam splitter, it is reflected by it and thus guided to the isolation output unit.

8. A multi-wavelength dispersion compensation device based on a fiber Bragg grating as described in claim 1 or 7, characterized in that, The isolation output unit includes an isolator and an output collimator arranged in sequence. The isolator allows light from the polarization beam splitting rotation unit to pass in the direction of the output collimator and suppresses backlight.

9. A multi-wavelength dispersion compensation device based on a fiber Bragg grating as described in claim 4, characterized in that, The fiber grating is configured to reflect light from the first and second ports to achieve dispersion compensation, and to transmit light from the third and fourth ports.

10. A multi-wavelength dispersion compensation system, characterized in that, It includes at least two fiber optic grating-based multi-wavelength dispersion compensation devices as described in any one of claims 1 to 9, wherein the at least two devices are arranged in parallel or cascaded to achieve dispersion compensation for more wavelength channels.

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