Optical buffer based on optical fiber array

Abstract

The invention relates to an optical buffer based on an optical fiber array. The optical buffer comprises an optical circulator, a two-dimensional optical fiber array, a collimating lens and a micro electro mechanical system (MEMS) which are arranged along the direction of an optical path, the travel of signal light in the delay optical fiber is doubled, the delay amount is doubled, and high-speed switching change among large-range multi-channel delay amounts can be realized in a small angle range by utilizing a single MEMS reflecting surface of a micro electro mechanical system (MEMS). The structure of the optical buffer is effectively simplified by using the MEMS, the usage amount of optical switches and optical circulators is reduced, and the cost is saved; due to the fact that the optical signals are transmitted back and forth twice through the delay optical fibers, time delay is doubled, that is, the needed length of each delay optical fiber is half of the length of the delay optical fiber used in a traditional structure, and space and the usage amount of the delay optical fibers can be saved. Furthermore, the cascade structure meets the requirements of wide-range and small-resolution application.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to an optical buffer based on an optical fiber array. Background Art

[0002] Optical buffers are used to store signals in optical information processing and are key components for high-performance packetized optical switching nodes. In packetized optical networks, all-optical buffers are not only the most effective means to solve the problem of optical packet congestion, implement traffic engineering and ensure QoS, but are also essential components for node tag extraction and routing selection, line-speed reading and variable-speed reading, and optical packet synchronization. The capacity, access speed and other characteristics of optical buffers directly determine the capacity, throughput, packet loss rate and other characteristics of switching nodes.

[0003] The existing technical data at home and abroad provide a lot of designs for realizing all-optical caching. It can be mainly divided into two categories: optical caching based on optical fiber delay lines and optical caching based on slow light effect. The optical caching technology based on optical fiber delay lines mainly realizes optical caching by changing the length of the optical fiber in combination with the use of optical switching, which can be divided into positive feedback optical caching and negative feedback optical caching. The positive feedback optical caching technology allows the same light packet to pass through the delay optical fiber only once, while the negative feedback optical caching technology can realize the circulation of light in the delay optical fiber. The optical caching technology based on the slow light effect achieves the effect of ultimately changing the group velocity of light transmission through different methods, thereby realizing the slow light effect and realizing optical caching. There are schemes that change the group refractive index and thus the group velocity by stimulated Brillouin scattering effect and stimulated Raman scattering effect; there are also schemes that realize optical caching by electromagnetically induced transparency technology; there are also schemes that realize optical caching by reducing the group velocity through special coupled resonance structures, etc. Among the above schemes, the optical buffering technology based on the optical fiber delay line uses a large number of optical switches, and the delay is limited by the length of the optical fiber. Although there is a design of optical buffering based on negative feedback, this scheme uses a large number of wavelength division multiplexers, semiconductor optical amplifiers, polarization controllers and other devices, with complex structure and complex control operation; for example, the tunable multi-loop multi-level optical buffer based on the N×N optical switch matrix disclosed in the Chinese invention patent with patent publication number CN101621718A has a complex structure and includes many optical switches and other structures.

[0004] In intersatellite communication applications, since the distance between satellites varies greatly but not rapidly, the intersatellite routing system requires a perfect combination of long range and small resolution. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides an optical buffer based on an optical fiber array.

[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0007] An optical buffer based on an optical fiber array, characterized in that:

[0008] Collimating lens;

[0009] A two-dimensional optical fiber array, the two-dimensional optical fiber array comprising a transmission optical fiber and a plurality of delay optical fibers with different lengths; one end of the delay optical fiber is coupled with a collimating lens, and the other end is provided with a high reflection structure;

[0010] An optical circulator, wherein the first port of the optical circulator is an input port; the second port of the optical circulator is connected to a transmission optical fiber; the third port of the optical circulator is an output port; signal light enters the transmission optical fiber from the second port after entering the first port, and output signal light enters the transmission optical fiber from the second port after entering the second port;

[0011] The micro-electromechanical system MEMS couples the signal light input from the transmission optical fiber into each delay optical fiber or couples the delayed optical signal reflected back from the delay optical fiber into the transmission channel for output.

[0012] Furthermore, the high-reflection structure is a high-reflection film arranged at the end of the delay optical fiber.

[0013] Furthermore, the high-reflection structure is a high-reflection collimator arranged at the end of the delay optical fiber.

[0014] Furthermore, a cascade structure is formed by connecting several optical buffers in series; the third port of one optical buffer is connected to the first port of another optical buffer to form a series connection.

[0015] Furthermore, the projection angle of the rotatable light reflecting part of the micro-electromechanical system MEMS is adjustable.

[0016] Furthermore, the micro-electromechanical system MEMS is an electrostatic MEMS, and includes a driving voltage adjustment unit for adjusting the projection angle of the rotatable light reflecting part.

[0017] Furthermore, the micro-electromechanical system MEMS is an electromagnetic MEMS, comprising a driving current adjustment unit for adjusting the projection angle of the rotatable light reflecting part.

[0018] Furthermore, in the cascade structure, one stage is a light buffer for large gradient changes, and another stage of the light buffer is a light buffer for subdividing the large gradient changes into small gradient changes.

[0019] The beneficial effects of the present invention are: the travel of the signal light in the delay optical fiber is doubled, the delay amount is doubled, and the single MEMS reflection surface of the micro-electromechanical system MEMS can realize high-speed switching changes between large-range multi-channel delay amounts in a small angle range. The use of the micro-electromechanical system MEMS effectively simplifies the structure of the optical buffer, reduces the use of optical switches and optical circulators, and saves costs; because the optical signal propagates back and forth twice through the delay optical fiber, the delay is doubled, that is, the required length of each delay optical fiber is half the length of the delay optical fiber used in the traditional structure, which can save space and the use of delay optical fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the structure of the present invention;

[0022] Figure 2 It is a schematic diagram of the cascade structure of the present invention;

[0023] Explanation of the reference numerals: 10, optical circulator; 11, first port; 12, second port; 13, third port; 20, two-dimensional optical fiber array; 21, transmission optical fiber; 22, delay optical fiber; 23, high-reflection structure; 30, collimating lens; 40, micro-electromechanical system MEMS. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] like Figure 1 As shown, an optical buffer based on an optical fiber array includes an optical circulator 10, a two-dimensional optical fiber array 20, a collimating lens 30, and a micro-electromechanical system MEMS 40 arranged along the optical path direction; the optical buffer of the present invention has a simple structure and only needs to use an optical circulator 10 structure; the first port 11 of the optical circulator 10 is an input end for receiving signal light; the second port 12 of the optical circulator 10 is connected to a transmission optical fiber 21; the third port 13 of the optical circulator 10 is an output end; the signal light enters from the first port 11 and then enters the transmission optical fiber 21 from the second port 12, and the output signal light enters from the second port 12 and then outputs from the third port 13;

[0028] The two-dimensional optical fiber array 20 includes a transmission optical fiber 21 and n delay optical fibers 22 with different lengths; one end of the delay optical fiber 22 is coupled to a collimating lens 30, and the other end is provided with a high-reflection structure 23; the high-reflection structure 23 is used to reflect the signal light in the delay optical fiber 22; in one embodiment, the high-reflection structure 23 is a high-reflection film arranged at the end of the delay optical fiber 22; in one embodiment, the high-reflection structure 23 is a high-reflection collimator arranged at the end of the delay optical fiber 22; in one embodiment, the high-reflection structure 23 is a Faraday reflector arranged at the end of the delay optical fiber 22; the length of the delay optical fiber 22 corresponds to different optical path differences, so that light caching can be achieved; the collimating lens 30 is used to collimate the light;

[0029] The micro-electro-mechanical system MEMS40 (Micro-Electro-Mechanical System) includes a rotatable light reflecting part, which couples the signal light input from the transmission optical fiber 21 into each delay optical fiber 22 or couples the delayed light signal reflected back from the delay optical fiber 22 into the transmission channel for output; there are tiny reflective lenses in the MEMS, and the reflective mirror surface can rotate in two dimensions under the control of the driving circuit; different voltages can obtain different scanning angles (rotation angles), and the signal light reflection is coupled into the delay optical fiber 22 or the transmission optical fiber 21 within the scanning range; in one embodiment, the projection angle of the rotatable light reflecting part of the micro-electro-mechanical system MEMS40 is adjustable; in one embodiment, the micro-electro-mechanical system MEMS40 is an electrostatic MEMS, including a driving voltage adjustment unit for adjusting the projection angle of the rotatable light reflecting part; in one embodiment, the micro-electro-mechanical system MEMS40 is an electromagnetic MEMS, including a driving current adjustment unit for adjusting the projection angle of the rotatable light reflecting part;

[0030] Working principle: signal light is input from the first port 11 of the optical circulator 10, output from the second port 12 and enters the transmission optical fiber 21, and is further collimated by the collimating lens 30 and irradiated onto the reflection surface of the micro-electromechanical system MEMS40. According to the angle corresponding to the MEMS, the signal light is reflected into different channels of the two-dimensional optical fiber array 20, that is, into different delay optical fibers 22. The reflectors at the ends of the delay optical fibers 22 in different channels reflect the light back to the micro-electromechanical system MEMS40, and the micro-electromechanical system MEMS40 then reflects and couples the delayed optical signal into the transmission channel for output. The output signal light enters from the second port 12 and is output from the third port 13. In this process, the travel distance of the signal light in the delay optical fiber 22 is doubled, and the delay amount is doubled. By utilizing the single MEMS reflection surface of the micro-electromechanical system MEMS40, high-speed switching between a large range of multi-channel delay amounts can be achieved within a small angle range.

[0031] like Figure 1 As shown, the lengths of the delay optical fibers 22 are L1, L2, ..., Ln, respectively, and the optical path lengths of different channels are 2Ln. Delay optical fibers 22 of different lengths correspond to different optical path length differences. It is defined that the lengths L1, L2, ..., Ln of n delay optical fibers 22 increase in sequence and form an arithmetic progression, the tolerance is d, the optical path length difference ΔL between adjacent delay optical fibers 22 is ΔL=2d, and the time delay S=iΔL / C, where C is the speed of light, and i=n-1;

[0032] like Figure 2As shown, a cascade structure is formed by two optical buffers connected in series; the third port 13 of one of the optical buffers is connected to the first port 11 of the other optical buffer to form a series connection; the length of the delay optical fiber 22 of the optical buffer located at the top increases successively and forms an arithmetic progression, and the optical path difference between adjacent delay optical fibers 22 is ΔL1; the length of the delay optical fiber 22 of the optical buffer located at the bottom increases successively and forms an arithmetic progression, and the optical path difference between adjacent delay optical fibers 22 is ΔL2; then the optical path variable range of the cascade array fiber optical buffer Δ=iΔL1+jΔL2; in one embodiment, the optical path variable range can be subdivided within ΔL1, that is, ΔL1=nΔL2; in one embodiment, the optical path variable range can be subdivided within ΔL2, that is, nΔL1=ΔL2;

[0033] In one embodiment, two optical buffers are set to form a cascade structure; the first-level optical buffer includes 10 delay optical fibers 22, forming 10 optical channels, and the delay variation between the delay optical fibers 22 is the same. The first-level optical buffer can achieve a delay of 1T, 2T, 3T...10T, where T is the delay time; the second-level optical buffer also includes 10 delay optical fibers 22, forming 10 optical channels, and the delay variation between the delay optical fibers 22 is the same, but the delay variation of the second-level optical buffer is set to 0.1T, then the second-level optical buffer can achieve a delay of 0.1T, 0.2T, 0.3T...1.0T, and after forming a cascade structure, the variation range can be between 0.1T and 10.9T, taking into account a resolution as small as 0.1T; further, a three-level cascade can be set to further reduce the resolution, for example, the delay variation of the third-level optical buffer is set to 0.01T;

[0034] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An optical buffer based on an optical fiber array, characterized in that: include A collimating lens (30); A two-dimensional optical fiber array (20), the two-dimensional optical fiber array (20) comprising a transmission optical fiber (21) and a plurality of delay optical fibers (22) with different lengths; one end of the delay optical fiber (22) is coupled to a collimating lens (30), and the other end is provided with a high reflection structure (23); An optical circulator (10), wherein a first port (11) of the optical circulator (10) is an input port; a second port (12) of the optical circulator (10) is connected to a transmission optical fiber (21); a third port (13) of the optical circulator (10) is an output port; signal light enters the transmission optical fiber (21) from the second port (12) after entering the first port (11); and output signal light enters the transmission optical fiber (21) from the second port (12) and is output from the third port (13); The micro-electromechanical system MEMS (40) couples the signal light input from the transmission optical fiber (21) into each delay optical fiber (22) or couples the delayed optical signal reflected back from the delay optical fiber (22) into the transmission channel for output.

2. The optical buffer based on the optical fiber array according to claim 1, characterized in that: The high-reflection structure (23) is a high-reflection film arranged at the end of the delay optical fiber (22).

3. The optical buffer based on the optical fiber array according to claim 1, characterized in that: The high-reflection structure (23) is a high-reflection collimator arranged at the end of the delay optical fiber (22).

4. The optical buffer based on the optical fiber array according to claim 1, characterized in that: A cascade structure is formed by connecting several optical buffers in series; the third port (13) of one optical buffer is connected to the first port (11) of another optical buffer to form a series connection.

5. The optical buffer based on the optical fiber array according to claim 1, characterized in that: The projection angle of the rotatable light reflecting part of the micro-electromechanical system MEMS (40) is adjustable.

6. The optical buffer based on the optical fiber array according to claim 1, characterized in that: The micro-electromechanical system (MEMS) (40) is an electrostatic MEMS, and comprises a driving voltage adjustment unit for adjusting the projection angle of the rotatable light reflecting part.

7. The optical buffer based on the optical fiber array according to claim 1, characterized in that: The micro-electromechanical system (MEMS) (40) is an electromagnetic MEMS, and comprises a driving current adjustment unit for adjusting the projection angle of the rotatable light reflecting part.

8. The optical buffer based on the optical fiber array according to claim 4, characterized in that: In the cascade structure, one stage is a light buffer for large gradient changes, and another stage is a light buffer for subdividing the large gradient changes into small gradient changes.

Images