Long and short parallel optical buffer based on multi-core optical fiber

Abstract

The invention provides a long and short parallel optical buffer based on a multi-core optical fiber, and belongs to the technical field of optical communication buffer. The long-short parallel optical buffer is composed of a multi-core optical fiber, an optical circulator, a multi-core optical fiber fan-in and fan-out device, an erbium-doped amplifier and an optical switch, the optical circulator, an optical path switch and a fiber core of the same multi-core optical fiber are utilized to construct two optical signal circulation loops suitable for different delay demand characteristics, and the long-short parallel optical buffer is formed. According to the invention, the long and short parallel optical buffers are constructed by using the fiber cores in the multi-core optical fiber, and the optical path circulation loss characteristic is considered based on the characteristics of small spacing and low crosstalk between the fiber cores of the multi-core optical fiber; a plurality of fiber cores in the same multi-core optical fiber are creatively utilized to construct an optical signal circulation loop with adjustable time delay as a long cache loop, and a single fiber core is utilized to construct an optical signal circulation loop with adjustable time delay as a short cache loop, so that adjustable time delay and efficient cache of optical signals are realized.

Description

Technical Field

[0001] This invention relates to the field of optical communication buffering technology, and in particular to a long and short parallel optical buffer based on multi-core optical fiber. Background Technology

[0002] With the rapid development of data centers and high-speed optical communication networks, the demand for optical signal buffering technology is increasing. In optical communication networks, optical buffering technology is key to achieving signal synchronization, traffic management, and conflict resolution. Traditional fiber-based optical buffers typically employ fiber loops or single-core fiber structures, which have significant limitations. For example, in dual-loop coupled all-optical buffers, the delay adjustment range is limited, making it difficult to simultaneously meet the application requirements of short latency (e.g., nanoseconds) and long latency (e.g., microseconds). Single-core fiber delay lines use a single single-mode fiber wound with a fixed-length delay coil, resulting in insufficient delay flexibility, a fixed buffering time, and an inability to dynamically adapt to varying network traffic. Furthermore, these devices are relatively large. In addition, traditional solutions also have shortcomings in signal loss and resource utilization, making them difficult to adapt to the high-capacity, low-latency requirements of modern optical communication.

[0003] The rise of multi-core fiber technology offers a new approach to solving the aforementioned problems. Compared to traditional single-core fiber, multi-core fiber possesses unique spatial multiplexing characteristics. Its core array can achieve parallel transmission of multiple cores within a standard cladding, and a single multi-core fiber can provide several times the physical channel capacity of a traditional single-core fiber. The parallel transmission characteristic of multi-core fibers can significantly improve buffer capacity and flexibility, and reduce equipment size; however, current technologies have not fully explored its potential in the field of optical buffering. How to utilize multi-core fibers to achieve tunable, low-loss long and short parallel buffering and simplify system architecture remains an unresolved issue. Summary of the Invention

[0004] In view of this, the present invention provides a long-short parallel optical buffer structure based on multi-core optical fibers to achieve adjustable delay and efficient buffering of optical signals. The structure is simple and solves the problems of poor delay flexibility and limited delay adjustment range of traditional optical buffers. It can effectively meet the dynamic traffic scheduling requirements in data centers and optical switching networks, providing an efficient signal buffering solution for high-speed optical communication systems.

[0005] The technical solution adopted by the embodiments of the present invention to solve its technical problem is as follows:

[0006] A long-short parallel optical buffer based on multi-core optical fiber includes: a multi-core optical fiber, an optical circulator, a multi-core optical fiber fan-in / fan-out unit, an erbium-doped amplifier, and an optical switch. The long-short parallel buffer structure is constructed using the cores of the multi-core optical fiber, wherein:

[0007] The two ends of the multi-core optical fiber are respectively connected to the first multi-core optical fiber fan-in fan-out device (21) and the second multi-core optical fiber fan-in fan-out device (22). Each switch and circulator establishes a connection relationship with the fiber core in the multi-core optical fiber through the first multi-core optical fiber fan-in fan-out device (21) and the second multi-core optical fiber fan-in fan-out device (22). Each switch guides the optical signal transmission path by changing the on / off relationship between the internal ports.

[0008] In the short buffer structure, a first optical circulator (11), a first erbium-doped amplifier (41), a second optical switch (52), a first optical switch (51), and the first fiber core (31) of the multi-core optical fiber are connected sequentially from end to end along the transmission direction of the short buffer loop optical path. The fiber tail of the first optical circulator (11) is connected to the first optical switch (51). The optical signal that needs to be short buffered enters the short buffer structure from the first optical circulator (11), and then enters the short buffer loop optical path through the first optical switch (51). The first optical switch (51) and the second optical switch (52) conduct the short buffer loop optical path during the required loop time period. The second optical switch (52) cuts off the loop and guides the optical signal output at the end of the required loop time.

[0009] In the long buffer structure, a second optical circulator (12), an alternating connection structure consisting of N optical switches providing output ends and N-1 multi-core optical fiber cores, an optical switch without output ends, and the Nth multi-core optical fiber core are connected sequentially along the transmission direction of the long buffer loop optical path. The fiber tail of the second optical circulator (12) is connected to the optical switch without output ends. The alternating connection structure adopts a Z-type connection, with a second erbium-doped amplifier (42) connected in the middle. The optical signal that needs to be buffered enters the long buffer structure from the second optical circulator (12), enters the long buffer loop optical path through the optical switch without output ends, and each optical switch conducts the long buffer loop optical path together during the required loop time period. Each optical switch providing output ends cuts off the loop and guides the optical signal output at the end of the required loop time.

[0010] Preferably, the unit delay t corresponding to a single fiber core is expressed as:

[0011] t = Ln g / c

[0012] Where L is the fiber length; n g is the mode group index of the optical fiber, and c is the speed of light in a vacuum;

[0013] The delay T1 of the optical signal in the short buffer structure is expressed as:

[0014] T1=N1t

[0015] In the formula, N1 is the number of loops within the closed loop.

[0016] Preferably, the delay T2 of the optical signal in the long buffer structure is expressed as:

[0017] T2 = N2 × Nt + nt, N2 ≥ 0, n ≥ 0

[0018] In the formula, N2 is the number of cycles, n is the number of fiber cores passed through after N2 cycles, and N represents the number of multi-fiber cores occupied by the long buffer cycle optical path.

[0019] Preferably, in the short cache structure:

[0020] The first optical circulator (11) has port A11A for input signal, port B11B connected to port b51b of the first optical switch (51), port C11C connected to port A1 of the first multi-core fiber fan-in / fan-out unit (21), and port D11D connected to the input of the first erbium-doped amplifier (41); port a51a of the first optical switch (51) is connected to port A2 of the second multi-core fiber fan-in / fan-out unit (22), and port c51c connected to port b52b of the second optical switch (52); port a52a of the second optical switch (52) is connected to the output of the first erbium-doped amplifier (41), and port c52c is used as the signal output; the first fiber core (31) is connected between port A1 and port A2.

[0021] When the first optical switch (51) is connected between port a and port b, it supports the initial entry of optical signals into the short buffer loop optical path; when the first optical switch (51) is adjusted to be connected between port a and port c, and the second optical switch (52) is connected between port a and port b, the short buffer loop optical path is a pass; when the second optical switch (52) is adjusted to be connected between port a and port c, it supports the output of optical signals.

[0022] Preferably, in the short buffer structure, after the optical signal is input from port A 11A and output from port B 11B of the first optical circulator (11), ports a and b of the first optical switch are turned on. After passing through the first fiber core (31), the optical signal enters from port C 11C of the first optical circulator (11) and is output from port D 11D. After passing through the first erbium-doped amplifier (41), it reaches the second optical switch (52). If the buffer requirement is met, the second optical switch (52) outputs a and c signals. The delay at this time is t.

[0023] If the buffering requirement is not met, ports a and b of the second optical switch (52) are turned on, ports a and c of the first optical switch (51) are turned on, and the optical signal passes through the first fiber core (31) again and enters port C 11C of the first optical circulator (11) before being output from port D 11D. The signal circulates within the closed loop. If the buffering requirement is met after N1 cycles, ports a and c of the second optical switch (52) are turned on, and the signal is output. The delay is T1.

[0024] Preferably, in the long cache structure, let N = 6:

[0025] The second optical circulator (12) has its A port 12A used for input signals, its B port 12B connected to the b port 53b of the third optical switch (53), its C port 12C connected to the B1 port of the first multi-core fiber fan-in / fan-out unit (21), and its D port 12D connected to the a port 54a of the fourth optical switch (54). The a port 53a of the third optical switch (53) is connected to the B2 port of the second multi-core fiber fan-in / fan-out unit (22), and its c port 53c is connected to the b port 59b of the ninth optical switch (59). The b port 54b of the fourth optical switch (54) is connected to the first... The G1 port and c port 54c of the multi-core fiber fan-in fan-out unit (21) are signal output terminals; the a port 55a of the fifth optical switch (55) is connected to the G2 port of the second multi-core fiber fan-in fan-out unit (22), the b port 55b is connected to the F2 port of the second multi-core fiber fan-in fan-out unit (22), and the c port 55c is a signal output terminal; the a port 56a of the sixth optical switch (56) is connected to the F1 port of the first multi-core fiber fan-in fan-out unit (21), the b port 56b is connected to the input terminal of the second erbium-doped amplifier (42), and the c port 56c is a signal output terminal; The output of the second erbium-doped amplifier (42) is connected to the E1 port of the first multi-core fiber fan-in / fan-out amplifier (21); the a port 57a of the seventh optical switch (57) is connected to the E2 port of the second multi-core fiber fan-in / fan-out amplifier (22), the b port 57b is connected to the D2 port of the second multi-core fiber fan-in / fan-out amplifier (22), and the c port 57c is the signal output terminal; the a port 58a of the eighth optical switch (58) is connected to the D1 port of the first multi-core fiber fan-in / fan-out amplifier (21), the b port 58b is connected to the C1 port of the first multi-core fiber fan-in / fan-out amplifier (21), and the c port 57c is the signal output terminal. Port 58c is the signal output terminal; port 59a of the ninth optical switch (59) is connected to the C2 terminal of the second multi-core fiber fan-in fan-out unit (22), and port 59c is the signal output terminal; the second fiber core (32) is connected between port B1 and port B2; the third fiber core (33) is connected between port C1 and port C2; the fourth fiber core (34) is connected between port D1 and port D2; the fifth fiber core (35) is connected between port E1 and port E2; the sixth fiber core (36) is connected between port F1 and port F2; and the seventh fiber core (37) is connected between port G1 and port G2.

[0026] When the third optical switch (53) is connected between ports a and b, it supports the initial entry of optical signals into the long buffer loop optical path; when the third optical switch (53) is adjusted to be connected between ports a and c, and ports a and b are connected in the other optical switches, the long buffer loop optical path is a pass; when any optical switch providing an output end is adjusted to be connected between ports a and c, it supports optical signal output.

[0027] Preferably, in the long cache structure:

[0028] After the optical signal is input from port A 12A and output from port B 12B of the second optical circulator (12), ports a and b of the third optical switch (53) are turned on. After passing through the second fiber core (32), the optical signal enters from port C 12C of the second optical circulator (12) and is output from port D 12D. According to the buffering requirements, when the optical signal reaches the ninth optical switch (59) for the N2nd time and is output, the corresponding time delay is T2 = N2 × 6t. When the optical signal passes through the ninth optical switch (59) for the N2nd time and is output at the fourth optical switch (54), the fifth optical switch (55), the sixth optical switch (56), the seventh optical switch (57), and the eighth optical switch (58), the corresponding time delays T2 are N2 × 6t + t, N2 × 6t + 2t, N2 × 6t + 3t, ​​N2 × 6t + 4t, and N2 × 6t + 5t, respectively, and N2 ≥ 0.

[0029] Preferably, the optical circulator is a four-port circulator.

[0030] Preferably, the number of fiber cores in the multi-core optical fiber is not less than N+1.

[0031] As described above, this invention provides a parallel optical buffer based on multi-core optical fiber, used to achieve adjustable delay and efficient buffering of optical signals. It is constructed from an optical circulator, multi-core optical fiber fan-in / fan-out units, multi-core optical fiber, erbium-doped amplifier, and optical switches. According to the buffer length requirements, the buffered signals are fed into the multi-core optical fiber through the fan-in / fan-out units. Short buffer requirements are fed into the short buffer structure, where a single fiber core and the optical switch control the number of cycles and signal output in the short buffer loop. Long buffer requirements are fed into the long buffer structure, where N fiber cores and the optical switch control the number of cycles and the signal output position corresponding to the buffer duration. This invention achieves adjustable delay and efficient buffering of parallel optical signals. It has a simple structure and solves problems such as poor delay flexibility and limited delay adjustment range in some traditional optical buffers. It can effectively meet the dynamic traffic scheduling requirements in data centers and optical switching networks, providing an efficient signal buffering solution for high-speed optical communication systems. Attached Figure Description

[0032] Figure 1 The present invention provides a long-short parallel optical buffer structure based on multi-core optical fiber;

[0033] Figure 2 An end-face view of the multi-core optical fiber provided by this invention;

[0034] In the figure: First optical circulator 11, Second optical circulator 12, First multi-core fiber fan-in fan-out 21, Second multi-core fiber fan-in fan-out 22, Seven fiber cores of multi-core fiber (31, 32, 33, 34, 35, 36, 37), Multi-core fiber cladding 38, Multi-core fiber coating 39, Multi-core fiber protective shell 30, First erbium-doped amplifier 41, Second erbium-doped amplifier 42, First optical switch 51, Second optical switch 52, Third optical switch 53, Fourth optical switch 54, Fifth optical switch 55, Sixth optical switch 56, Seventh optical switch 57, Eighth optical switch 58, Ninth optical switch 59. Detailed Implementation

[0035] The technical solution and effects of the present invention will be further described in detail below with reference to the accompanying drawings.

[0036] Multi-core optical fibers, as a novel type of microstructured optical fiber, offer several advantages, such as transmission capacity several times that of traditional single-core optical fibers, higher device integration density, and smaller size. Therefore, utilizing multi-core optical fibers as buffers can potentially significantly reduce the structural complexity and size of optical buffers while improving integration density and reliability. This invention also leverages the fast unidirectional transmission characteristics of multi-core optical fibers, constructing a loop using the fiber cores and applying it to the optical buffer structure. Buffer requirements are typically categorized as long buffers and short buffers. This invention utilizes the same multi-core optical fiber to construct a parallel long and short buffer structure, achieving comprehensive functionality while effectively reducing device size. The signal transmission method employed in the long buffer loop optical path constructed in this invention maintains a relatively consistent level of fiber core loss, effectively avoiding device replacement frequency caused by excessive loss in a single fiber core.

[0037] refer to Figure 1 As shown, this invention provides a long-short parallel optical buffer based on multi-core optical fiber, comprising a multi-core optical fiber, an optical circulator, a multi-core optical fiber fan-in / fan-out unit, an erbium-doped amplifier, and an optical switch. The long-short parallel buffer structure is constructed using the cores of the multi-core optical fiber, wherein:

[0038] The first multi-core fiber fan-in fan-out device (21) and the second multi-core fiber fan-in fan-out device (22) are connected to the two ends of the multi-core fiber respectively. Each switch and circulator establishes a connection relationship with the fiber core in the multi-core fiber through the first multi-core fiber fan-in fan-out device (21) and the second multi-core fiber fan-in fan-out device (22). Each switch guides the optical signal transmission path by changing the on / off relationship between the internal ports.

[0039] In the short buffer structure, a first optical circulator (11), a first erbium-doped amplifier (41), a second optical switch (52), a first optical switch (51), and the first fiber core (31) in the multi-core fiber are connected sequentially from end to end along the transmission direction of the short buffer loop optical path. The fiber tail of the first optical circulator (11) is connected to the first optical switch (51). The optical signal that needs to be short buffered enters the short buffer structure from the first optical circulator (11), and then enters the short buffer loop optical path through the first optical switch (51). The first optical switch (51) and the second optical switch (52) conduct the short buffer loop optical path during the required loop time period. The second optical switch (52) cuts off the loop and guides the optical signal output at the end of the required loop time.

[0040] In the long buffer structure, along the transmission direction of the long buffer loop optical path, there are a second optical circulator (12), an alternating connection structure consisting of N optical switches providing output ends and N-1 multi-core optical fiber cores, an optical switch without output ends, and the Nth multi-core optical fiber core; the fiber tail of the second optical circulator (12) is connected to an optical switch without output ends; the alternating connection structure adopts a Z-type connection, and the middle part is connected to a second erbium-doped amplifier (42); the optical signal that needs to be buffered enters the long buffer structure from the second optical circulator (12), enters the long buffer loop optical path through the optical switch without output ends, and each optical switch conducts the long buffer loop optical path together during the required loop time period. Each optical switch providing output ends cuts off the loop and guides the optical signal output at the end of the required loop time.

[0041] Accordingly, the unit delay t for a single fiber core is expressed as:

[0042] t = Ln g / c (1)

[0043] Where L is the fiber length; n g is the mode group index of the optical fiber, and c is the speed of light in a vacuum;

[0044] The expression for the delay T1 of the optical signal in the short buffer structure is:

[0045] T1=N1t (2)

[0046] In the formula, N1 is the number of loops within the closed loop. (Since both the four-port optical circulator and the optical switch have direct fiber tail connections, it is not necessary to calculate the time taken for the optical signal to travel in the circulator and the optical switch; only the transmission time in the multi-core optical fiber needs to be considered.)

[0047] The delay T2 of the optical signal in the long buffer structure is expressed as:

[0048] T2=N2×Nt+nt, N2≥0,n≥0 (3)

[0049] In the formula, N2 is the number of cycles, n is the number of fiber cores passed through after N2 cycles, and N represents the number of multi-fiber cores occupied by the long buffer cycle optical path.

[0050] This invention does not impose any restrictions on the number of short buffer structures and long buffer structures to be constructed for a single multi-core optical fiber. It is assumed that there is at least one short buffer structure and one long buffer structure in the optical buffer. In the actual design process, it is necessary to make specific adjustments based on the number of fiber cores of the multi-core optical fiber and the number of fiber cores N occupied by the long buffer structure, so as to flexibly support the implementation of long and short parallel buffers.

[0051] The following is a specific embodiment, for reference. Figure 2 As shown, a multi-core optical fiber with a 7-core structure is used to construct a parallel optical buffer of short and long lengths. The first core (31) is used to construct the short buffer structure, while the remaining cores (31, 32, 33, 34, 35, 36, 37) are used to construct the long buffer structure. All optical switches are 1*2 optical switches, and each optical circulator is a four-port circulator. The specific connection method is as follows:

[0052] Figure 1 The equipment includes: a first optical circulator (11), a second circulator (12), a first multi-core fiber fan-in fan-out unit (21), a second multi-core fiber fan-in fan-out unit (22), seven multi-core fiber cores (31, 32, 33, 34, 35, 36, 37), a first erbium-doped amplifier (41), a second erbium-doped amplifier (42), a first optical switch (51), a second optical switch (52), a third optical switch (53), a fourth optical switch (54), a fifth optical switch (55), a sixth optical switch (56), a seventh optical switch (57), an eighth optical switch (58), and a ninth optical switch (59).

[0053] Circulators are used to guide optical signals into multi-core optical fibers and realize signal buffering and circulation; multi-core optical fiber fan-in and fan-out devices are used to realize high-efficiency coupling between each core of a multi-core optical fiber and several single-mode optical fibers; multi-core optical fibers are used to realize buffered signal transmission; erbium-doped fiber amplifiers are used to amplify signals to compensate for transmission loss; optical switches are used to control signal paths and delay adjustment.

[0054] The first four-port optical circulator (11) has port A as port 1, port B as port 2, port C as port 3, and port D as port 4; the second four-port optical circulator (12) is the same as the first four-port optical circulator (11), with port A as port 1, port B as port 2, port C as port 3, and port D as port 4.

[0055] The seven ports of the first multi-core fiber fan-in fan-out (21) are A1, B1, C1, D1, E1, F1, and G1 as shown in the figure; the seven ports of the second multi-core fiber fan-in fan-out (22) are A2, B2, C2, D2, E2, F2, and G2 as shown in the figure; wherein, A1 of the first multi-core fiber fan-in fan-out (21) and A2 of the second multi-core fiber fan-in fan-out (22) are connected to the first fiber core (31); B1 of the first multi-core fiber fan-in fan-out (21) and B2 of the second multi-core fiber fan-in fan-out (22) are connected to the second fiber core (32); C1 of the first multi-core fiber fan-in fan-out (21) and the second multi-core fiber fan-in fan-out (22) are connected to the second multi-core fiber fan-out (22). The third fiber core (33) is connected between C2 of the first multi-core fiber fan-in fan-out (21); the fourth fiber core (34) is connected between D1 of the first multi-core fiber fan-in fan-out (21) and D2 of the second multi-core fiber fan-in fan-out (22); the fifth fiber core (35) is connected between E1 of the first multi-core fiber fan-in fan-out (21) and E2 of the second multi-core fiber fan-in fan-out (22); the sixth fiber core (36) is connected between F1 of the first multi-core fiber fan-in fan-out (21) and F2 of the second multi-core fiber fan-in fan-out (22); the seventh fiber core (37) is connected between G1 of the first multi-core fiber fan-in fan-out (21) and G2 of the second multi-core fiber fan-in fan-out (22).

[0056] All optical switches are 1*2 optical switches, with three ports a, b, and c respectively.

[0057] The specific connection method in the short cache structure is as follows:

[0058] The first optical circulator (11) has port A11A for input signals, port B11B connected to port b51b of the first optical switch (51) (connected by the circulator's fiber tail), port C11C connected to port A1 of the first multi-core fiber fan-in / fan-out unit (21), and port D11D connected to the input of the first erbium-doped amplifier (41) (connected by the circulator's fiber tail); port a51a of the first optical switch (51) is connected to port A2 of the second multi-core fiber fan-in / fan-out unit (22), and port c51c connected to port b52b of the second optical switch (52); port a52a of the second optical switch (52) is connected to the output of the first erbium-doped amplifier (41), and port c52c is used as the signal output; the first fiber core (31) is connected between port A1 and port A2;

[0059] When the first optical switch (51) is connected between ports a and b, it supports the initial entry of optical signals into the short buffer loop optical path; when the first optical switch (51) is adjusted to be connected between ports a and c, and the second optical switch (52) is connected between ports a and b, the short buffer loop optical path is open; when the second optical switch (52) is adjusted to be connected between ports a and c, it supports the output of optical signals.

[0060] In the short buffer structure, after the optical signal is input from port A11A and output from port B11B of the first optical circulator (11), ports a and b of the first optical switch are turned on. After passing through the first fiber core (31), the optical signal enters from port C11C of the first optical circulator (11) and is output from port D11D. After passing through the first erbium-doped amplifier (41), it reaches the second optical switch (52). If the buffer requirement is met, the second optical switch (52) outputs a signal from ports a and c. The buffer path is: 11(A)-11(B)-51(b)-51(a)-22(A2)-21(A1)-11(C)-11(D)-41-52(a)-52(c). The delay at this time is t, which is the minimum delay of this path.

[0061] If the buffering requirement is not met, ports a and b of the second optical switch (52) are turned on, and ports a and c of the first optical switch (51) are turned on. The optical signal passes through the first fiber core (31) again and enters port C 11C of the first optical circulator (11), and is output from port D 11D. It circulates within the closed loop. If the buffering requirement is met after N1 cycles, ports a and c of the second optical switch (52) are turned on, and the signal is output. The buffering path is 11(A)-11(B). -51(b)-51(a)-22(A2)-21(A1)-11(C)-11(D)-41-52(a)-52(b)-51(c)-51(a)-22(A2) is a loop; one loop is completed by passing through the first fiber core (31), the loop path is 51(a)-22(A2)-21(A1)-11(C)-11(D)-41-52(a), and the delay is T1=N1t.

[0062] In the long cache structure, let N=6, and the specific connection method is as follows:

[0063] The second optical circulator (12) has its A port 12A used for input signals, its B port 12B connected to the b port 53b of the third optical switch (53) (connected by the circulator's fiber tail), its C port 12C connected to the B1 port of the first multi-core fiber fan-in / fan-out unit (21), and its D port 12D connected to the a port 54a of the fourth optical switch (54) (connected by the circulator's fiber tail); the third optical switch (53) has its a port 53a connected to the B2 port of the second multi-core fiber fan-in / fan-out unit (22), and its c port 53c connected to the b port 59b of the ninth optical switch (59); the fourth optical switch... The first optical switch (54) has port 54b connected to port G1 of the first multi-core fiber fan-in / fan-out unit (21), and port 54c is the signal output terminal; the fifth optical switch (55) has port a 55a connected to port G2 of the second multi-core fiber fan-in / fan-out unit (22), port b 55b connected to port F2 of the second multi-core fiber fan-in / fan-out unit (22), and port c 55c is the signal output terminal; the sixth optical switch (56) has port a 56a connected to port F1 of the first multi-core fiber fan-in / fan-out unit (21), port b 56b connected to the input terminal of the second erbium-doped amplifier (42), and port c 56... c is the signal output terminal; the output terminal of the second erbium-doped amplifier (42) is connected to the E1 port of the first multi-core fiber fan-in fan-out (21); the a port 57a of the seventh optical switch (57) is connected to the E2 port of the second multi-core fiber fan-in fan-out (22), the b port 57b is connected to the D2 port of the second multi-core fiber fan-in fan-out (22), and the c port 57c is the signal output terminal; the a port 58a of the eighth optical switch (58) is connected to the D1 port of the first multi-core fiber fan-in fan-out (21), the b port 58b is connected to the C1 port of the first multi-core fiber fan-in fan-out (21), and the c port 57c is the signal output terminal. Port 58c is the signal output terminal; port 59a of the ninth optical switch (59) is connected to the C2 terminal of the second multi-core fiber fan-in fan-out unit (22), and port 59c is the signal output terminal; the second fiber core (32) is connected between port B1 and port B2; the third fiber core (33) is connected between port C1 and port C2; the fourth fiber core (34) is connected between port D1 and port D2; the fifth fiber core (35) is connected between port E1 and port E2; the sixth fiber core (36) is connected between port F1 and port F2; and the seventh fiber core (37) is connected between port G1 and port G2.

[0064] When the third optical switch (53) is connected between ports a and b, it supports the initial entry of optical signals into the long buffer loop optical path; when the third optical switch (53) is adjusted to be connected between ports a and c, and the long buffer loop optical path is open when ports a and b are connected in the other optical switches; when any optical switch that provides an output is adjusted to be connected between ports a and c, it supports the output of optical signals.

[0065] The optical signal is input from port A 12A and output from port B 12B of the second optical circulator (12), and then output from port B to port B 53b of the third optical switch (53). With ports a and b of the third optical switch (53) turned on, the optical signal passes through the second fiber core (32), enters from port C 12C of the second optical circulator (12), and outputs from port D 12D. The fourth optical switch (54) controls the signal to select output or entry into the next stage of buffering, i.e., into the next fiber core, sequentially passing through the seventh fiber core (37), the sixth fiber core (36), etc., with a fixed delay t added at each stage. When a longer buffering time is required, the ninth optical switch (59) re-introduces the signal into the second fiber core (32) to form a large loop.

[0066] Specifically, case 1: If the buffering requirement is met at the fourth optical switch (54) after passing through the second fiber core (32), then the conduction signal is output from ports a and c of the fourth optical switch (54), and the time delay at this time is t; that is, from Figure 1 Its buffer path is: 12(A)-12(B)-53(b)-53(a)-22(B2)-21(B1)-12(C)-12(D)-54(a)-54(c); if the buffer requirement is not met, the fourth optical switch (54) a and b ports are turned on to enter the seventh fiber core (37);

[0067] Case 2: After the signal passes through the seventh fiber core (37), if the buffering requirement is met, the a and c ports of the fifth optical switch (55) are turned on, and the signal is output. The time delay at this time is 2t; that is, from Figure 1 Its buffer path is: 12(A)-12(B)-53(b)-53(a)-22(B2)-21(B1)-12(C)-12(D)-54(a)-54(b)-21(G1)-22(G2)-55(a)-55(c); if the buffer requirement is not met, the fifth optical switch (55) a and b ports are turned on to enter the sixth fiber core (36);

[0068] Case 3: After the signal passes through the sixth fiber core (36), if the buffering requirement is met, the sixth optical switch (56) will output a signal through ports a and c, with a time delay of 3t; that is, from Figure 1 Its buffer path is: 12(A)-12(B)-53(b)-53(a)-22(B2)-21(B1)-12(C)-12(D)-54(a)-54(b)-21(G1)-22(G2)-55(a)-55(b)-22(F2)-21(F1)-56(a)-56(c); if the buffer requirement is not met, the a and b ports of the sixth optical switch (56) are turned on, and the signal passes through the second erbium-doped amplifier (42) and then through the fifth fiber core (35);

[0069] Case 4: After the signal passes through the fifth fiber core (35), if the buffering requirement is met, the seventh optical switch (57) will output signals through ports a and c, with a delay of 4t. Figure 1 Its buffer path is: 12(A)-12(B)-53(b)-53(a)-22(B2)-21(B1)-12(C)-12(D)-54(a)-54(b)-21(G1)-22(G2)-55(a)-55(b)-22(F2)-21(F1)-56(a)-56(b)-42-21(E1)-22(E2)-57(a)-57(c); if the buffer requirement is not met, the seventh optical switch (57) a and b ports are turned on, and the signal enters the fourth fiber core (34);

[0070] Case 5: After the signal passes through the fourth fiber core (34), if the buffering requirement is met, the a and c ports of the eighth optical switch (58) will be turned on to output the signal. The time delay at this time is 5t; that is, from Figure 1 Its buffer path is: 12(A)-12(B)-53(b)-53(a)-22(B2)-21(B1)-12(C)-12(D)-54(a)-54(b)-21(G1)-22(G2)-55(a)-55(b)-22(F2)-21(F1)-56(a)-56(b)-42-21(E1)-22(E2)-57(a)-57(b)-22(D2)-21(D1)-58(a)-58(c); if the buffer requirement is not met, the eighth optical switch (58) a and b ports are turned on, and the signal enters the third fiber core (33);

[0071] Case 6: After the signal passes through the third fiber core (33), if the buffering requirement is met, the a and c ports of the ninth optical switch (59) are connected to output the signal. The time delay at this time is 6t; that is, from Figure 1 Its buffer path is: 12(A)-12(B)-53(b)-53(a)-22(B2)-21(B1)-12(C)-12(D)-54(a)-54(b)-21(G1)-22(G2)-55(a)-55(b)-22(F2)-21(F1)-56(a)-56(b)-42-21(E1)-22(E2)-57(a)-57(b)-22(D2)-21(D1)-58(a)-58(b)-21(C1)-22(C2)-59(a)-59(c); if the buffer requirement is not met, the ninth optical switch (59) a and b ports are turned on, and the third optical switch (53) a and c ports are turned on to re-enter the second fiber core (32);

[0072] Case 7: The eighth optical switch (58) is turned on at ports a and b, and the third optical switch (53) is turned on at ports a and c. The light then enters the second fiber core (32) and then the second four-port optical circulator (12) at port C (12C). After entering, the light is output from port D (12D). Figure 1 Its cache path is: 12(A)-12(B)-53(b)-53(a)-22(B2)-21(B1)-12(C)-12(D)-54(a)-54(b)-21(G1)-22(G2)-55(a)-55(b)-22(F2)-21(F1)-56(a)-56(b)-42-21(E1)-22(E2)-57( a)-57(b)-22(D2)-21(D1)-58(a)-58(b)-21(C1)-22(C2)-59(a)-59(b)-53(c)-53(a)-22(B1); The loop is performed within the above closed loop. If the buffer requirement is reached after N2 loops, the ninth optical switch (59) a and c ports are turned on and the delay is T2=N2×Nt;

[0073] Therefore, in the long buffer structure, according to the buffer requirements, when the optical signal arrives at the ninth optical switch (59) for the N2th time and is output, the corresponding delay is N2×6t. When the optical signal passes through the ninth optical switch (59) for the N2th time and is output at the fourth optical switch (54), the fifth optical switch (55), the sixth optical switch (56), the seventh optical switch (57), and the eighth optical switch (58), the corresponding delays T2 are N2×6t+t, N2×6t+2t, N2×6t+3t, N2×6t+4t, and N2×6t+5t, respectively, with N2≥0. If the buffer requirements are met after N2 cycles and the signal is output at the output port of the optical switch after passing through n fiber cores of the multi-core optical fiber, the delay is T3=N2×Nt+nt, where n is the number of fiber cores used after N2 cycles.

[0074] In summary, this invention provides a long-short parallel optical buffer based on multi-core optical fiber for achieving adjustable delay and efficient buffering of optical signals. Through an innovative multi-core optical fiber architecture and intelligent optical switch control, a breakthrough improvement in optical buffering performance is achieved. Compared with traditional single-core optical fiber buffering solutions, this design has the following significant advantages: (1) It flexibly achieves an ultra-wide delay range through a multi-core parallel architecture, and the innovative dual-path design can simultaneously meet both short and long delay requirements; (2) The use of a dynamically adjustable optical switch makes the buffering time controllable; (3) Through the parallel transmission characteristics of multi-core optical fiber, the device size is reduced, making it suitable for space-constrained data center deployment environments. This solution can be widely applied to latency-sensitive application scenarios such as data center optical switching, 5G fronthaul networks, and future 6G networks.

[0075] The embodiments disclosed in this specification are merely illustrative of one aspect of the invention, and the scope of protection of the invention is not limited to these embodiments. Any other functionally equivalent embodiments fall within the scope of protection of the invention. Those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the scope of protection of the claims of this invention.

Claims

1. A long-short parallel optical buffer based on multi-core optical fiber, characterized in that, include: Multi-core optical fibers, optical circulators, multi-core optical fiber fan-in / fan-out devices, erbium-doped amplifiers, and optical switches utilize the cores of the multi-core optical fiber to construct parallel buffer structures of varying lengths. The two ends of the multi-core optical fiber are respectively connected to the first multi-core optical fiber fan-in fan-out device (21) and the second multi-core optical fiber fan-in fan-out device (22). Each switch and circulator establishes a connection relationship with the fiber core in the multi-core optical fiber through the first multi-core optical fiber fan-in fan-out device (21) and the second multi-core optical fiber fan-in fan-out device (22). Each switch guides the optical signal transmission path by changing the on / off relationship between the internal ports. In the short buffer structure, a first optical circulator (11), a first erbium-doped amplifier (41), a second optical switch (52), a first optical switch (51), and the first fiber core (31) in the multi-core optical fiber are connected sequentially from end to end along the transmission direction of the short buffer loop optical path. The fiber tail of the first optical circulator (11) is connected to the first optical switch (51). The optical signal that needs to be buffered enters the short buffer structure from the first optical circulator (11), and then enters the short buffer loop optical path through the first optical switch (51). The first optical switch (51) and the second optical switch (52) conduct the short buffer loop optical path during the required loop time period. The second optical switch (52) cuts off the loop and guides the optical signal output when the required loop time ends. In the long buffer structure, a second optical circulator (12), an alternating connection structure consisting of N optical switches providing output ends and N-1 multi-core optical fiber cores, an optical switch without output ends, and the Nth multi-core optical fiber core are connected sequentially along the transmission direction of the long buffer loop optical path. The fiber tail of the second optical circulator (12) is connected to the optical switch without output ends. The alternating connection structure adopts a Z-type connection, with a second erbium-doped amplifier (42) connected in the middle. The optical signal that needs to be buffered enters the long buffer structure from the second optical circulator (12), enters the long buffer loop optical path through the optical switch without output ends, and each optical switch conducts the long buffer loop optical path together during the required loop time period. Each optical switch providing output ends cuts off the loop and guides the optical signal output at the end of the required loop time.

2. The long and short parallel optical buffer based on multi-core optical fiber as described in claim 1, characterized in that, The unit delay t corresponding to a single fiber core is expressed as: t=Ln g / c Where L is the fiber length; n g is the mode group index of the optical fiber, and c is the speed of light in a vacuum; The delay T1 of the optical signal in the short buffer structure is expressed as: T1=N1t In the formula, N1 is the number of loops within the closed loop.

3. The long and short parallel optical buffer based on multi-core optical fiber as described in claim 2, characterized in that, The delay T2 of the optical signal in the long buffer structure is expressed as: T2 = N2 × Nt + nt, N2 ≥ 0, n ≥ 0 In the formula, N2 is the number of cycles, n is the number of fiber cores passed through after N2 cycles, and N represents the number of multi-fiber cores occupied by the long buffer cycle optical path.

4. The long and short parallel optical buffer based on multi-core optical fiber as described in claim 2, characterized in that, In the short cache structure: The first optical circulator (11) has port A11A for input signal, port B11B connected to port b51b of the first optical switch (51), port C11C connected to port A1 of the first multi-core fiber fan-in / fan-out unit (21), and port D11D connected to the input of the first erbium-doped amplifier (41); port a51a of the first optical switch (51) is connected to port A2 of the second multi-core fiber fan-in / fan-out unit (22), and port c51c connected to port b52b of the second optical switch (52); port a52a of the second optical switch (52) is connected to the output of the first erbium-doped amplifier (41), and port c52c is used as the signal output; the first fiber core (31) is connected between port A1 and port A2. When the first optical switch (51) is connected between port a and port b, it supports the initial entry of optical signals into the short buffer loop optical path; when the first optical switch (51) is adjusted to be connected between port a and port c, and the second optical switch (52) is connected between port a and port b, the short buffer loop optical path is a pass; when the second optical switch (52) is adjusted to be connected between port a and port c, it supports the output of optical signals.

5. The long and short parallel optical buffer based on multi-core optical fiber as described in claim 4, characterized in that, In the short buffer structure, after the optical signal is input from port A 11A and output from port B 11B of the first optical circulator (11), ports a and b of the first optical switch are turned on. After passing through the first fiber core (31), the optical signal enters from port C 11C of the first optical circulator (11) and is output from port D 11D. After passing through the first erbium-doped amplifier (41), it reaches the second optical switch (52). If the buffer requirement is met, the second optical switch (52) outputs a and c signals. The delay at this time is t. If the buffering requirement is not met, ports a and b of the second optical switch (52) are turned on, ports a and c of the first optical switch (51) are turned on, and the optical signal passes through the first fiber core (31) again and enters port C 11C of the first optical circulator (11) before being output from port D 11D. The signal circulates within the closed loop. If the buffering requirement is met after N1 cycles, ports a and c of the second optical switch (52) are turned on, and the signal is output. The delay is T1.

6. The long and short parallel optical buffer based on multi-core optical fiber as described in claim 3, characterized in that, In the long cache structure, let N = 6: The second optical circulator (12) has its A port 12A used for input signals, its B port 12B connected to the b port 53b of the third optical switch (53), its C port 12C connected to the B1 port of the first multi-core fiber fan-in / fan-out unit (21), and its D port 12D connected to the a port 54a of the fourth optical switch (54). The a port 53a of the third optical switch (53) is connected to the B2 port of the second multi-core fiber fan-in / fan-out unit (22), and its c port 53c is connected to the b port 59b of the ninth optical switch (59). The b port 54b of the fourth optical switch (54) is connected to the first... The G1 port and c port 54c of the multi-core fiber fan-in fan-out unit (21) are signal output terminals; the a port 55a of the fifth optical switch (55) is connected to the G2 port of the second multi-core fiber fan-in fan-out unit (22), the b port 55b is connected to the F2 port of the second multi-core fiber fan-in fan-out unit (22), and the c port 55c is a signal output terminal; the a port 56a of the sixth optical switch (56) is connected to the F1 port of the first multi-core fiber fan-in fan-out unit (21), the b port 56b is connected to the input terminal of the second erbium-doped amplifier (42), and the c port 56c is a signal output terminal; The output of the second erbium-doped amplifier (42) is connected to the E1 port of the first multi-core fiber fan-in / fan-out amplifier (21); the a port 57a of the seventh optical switch (57) is connected to the E2 port of the second multi-core fiber fan-in / fan-out amplifier (22), the b port 57b is connected to the D2 port of the second multi-core fiber fan-in / fan-out amplifier (22), and the c port 57c is the signal output terminal; the a port 58a of the eighth optical switch (58) is connected to the D1 port of the first multi-core fiber fan-in / fan-out amplifier (21), the b port 58b is connected to the C1 port of the first multi-core fiber fan-in / fan-out amplifier (21), and the c port 57c is the signal output terminal. Port 58c is the signal output terminal; port 59a of the ninth optical switch (59) is connected to the C2 terminal of the second multi-core fiber fan-in fan-out unit (22), and port 59c is the signal output terminal; the second fiber core (32) is connected between port B1 and port B2; the third fiber core (33) is connected between port C1 and port C2; the fourth fiber core (34) is connected between port D1 and port D2; the fifth fiber core (35) is connected between port E1 and port E2; the sixth fiber core (36) is connected between port F1 and port F2; and the seventh fiber core (37) is connected between port G1 and port G2. When the third optical switch (53) is connected between ports a and b, it supports the initial entry of optical signals into the long buffer loop optical path; when the third optical switch (53) is adjusted to be connected between ports a and c, and ports a and b are connected in the other optical switches, the long buffer loop optical path is a pass; when any optical switch providing an output end is adjusted to be connected between ports a and c, it supports optical signal output.

7. The long and short parallel optical buffer based on multi-core optical fiber as described in claim 6, characterized in that, In the long cache structure: After the optical signal is input from port A 12A and output from port B 12B of the second optical circulator (12), ports a and b of the third optical switch (53) are turned on. After passing through the second fiber core (32), the optical signal enters from port C 12C of the second optical circulator (12) and is output from port D 12D. According to the buffering requirements, when the optical signal reaches the ninth optical switch (59) for the N2nd time and is output, the corresponding time delay is T2 = N2 × 6t. When the optical signal passes through the ninth optical switch (59) for the N2nd time and is output at the fourth optical switch (54), the fifth optical switch (55), the sixth optical switch (56), the seventh optical switch (57), and the eighth optical switch (58), the corresponding time delays T2 are N2 × 6t + t, N2 × 6t + 2t, N2 × 6t + 3t, ​​N2 × 6t + 4t, and N2 × 6t + 5t, respectively, and N2 ≥ 0.

8. The long and short parallel optical buffer based on multi-core optical fiber as described in claim 1, characterized in that, The optical circulator is a four-port circulator.

9. The long and short parallel optical buffer based on multi-core optical fiber as described in claim 1, characterized in that, The number of fiber cores in the multi-core optical fiber is not less than N+1.

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