A low-loss and low-crosstalk graded-index distribution three-mode mode division multiplexer

Abstract

The present invention proposes a three-mode mode division multiplexer with low loss, low crosstalk and graded refractive index distribution, which consists of three identical transmission channels, one of which is the main transmission channel; the radius of the transmission channel is 20 μm, and the core and cladding of the transmission channel The refractive index difference is 0.0015, and the cladding refractive index is 1.442524; the refractive index from the center of the channel core to the cladding changes gradually; the mode LP01 is directly input into the main transmission channel; the mode LP11a and LP11b channels are respectively placed in the main transmission channel cross section x and y In the direction, the channel length is 33mm, and the distance from the main channel is 6μm; in the 1400nm‑1700nm band, the coupling efficiency of the multiplexer is better than ‑0.479dB; the three modes of refractive index gradient distribution, low loss and low crosstalk are realized Modulus multiplexing.

Description

technical field [0001] The invention relates to a mode division multiplexing structure, in particular to a three-mode mode division multiplexer with low-loss and low-crosstalk graded refractive index distribution, which can be applied to new-generation information technology fields such as optical fiber communication and optical information processing. Background technique [0002] In recent years, the field of optical fiber communication based on mode division multiplexing has been one of the frontier research hotspots; as one of its key technologies, mode division multiplexing devices have received extensive attention [1 Guifang Li, Neng Bai, and Ningbo Zhao and Cen Xia, Space -division multiplexing: the next frontier in opticalcommunication. Advances in Optics & Photonics, 2014, 6(4):5041 – 5046; 2 HeWen, Hongjun Zheng, et al. Few-Mode Fiber-Optic Microwave Photonic Links,Light: Science & Applications, 2017.8, 6, e17021, 1-8]; As a key technical link of the mode division ...

AI Technical Summary

Problems solved by technology

Although the structural complexity of the "photonic lantern" is lower than that of the space coupler, its manufacturing process is precise and complex. It is very difficult to accurately control the position of the optical fiber when it is melted, the thickness and length of the tapered body, and it is difficult to mass produce; The output port formed by the taper does not exactly match the transmission channel, resulting in high loss

Literature [7 Shi Jian. Research on mode-division multiplexing communication technology based on few-mode fiber [D]. Jilin University, 2013] designed a mode-division multiplexer / demultiplexer based on asymmetric planar waveguide to realize mode multiplexing However, the planar multiplexer has the problems of narrow working band, difficult integration, and difficult fusion with optical fiber

Literature [8 HuangB, Xia C, Matz G, et al. Structured directional coupler pair for multiplexing of degenerate modes[C]. Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference (OFC / NFOEC), 2013: 1-3; 9Xie Y, Fu S, Liu H, et al. Design and numerical optimization of a modemultiplexer based on few-mode fiber couplers [J]. Journal of Optics, 2013, 15(12): 3901-3901; 10 Tsekrekos C P, Syvridis D. Symmetric Few-Mode FiberCouplers as the Key Component for Broadband Mode Multiplexing [J]. Journal of Lightwave Technology, 2014, 32(14): 2461-2467; 11 Simon Gross, Nicolas Riesen, John D. Love and Michael J. Withford, Mode-Division Multiplexingusing Femtosecond Laser Written 3-Dimensional Tapered Couplers, OECC / ACOFT2014.7, 156-158] designed a multiplexer with direct directional coupling of modes; the multiplexer has a simple manufacturing process and can be formed by using a three-dimensional waveguide or optical fiber Multiplexer; it can be directly fused with optical fiber and has a wide operating band; however, the transmission channel of this type of multiplexer has large nonlinearity and attenuation, and its design does not consider the high differential mode group delay of step-type optical fiber ; These problems and the mode crosstalk problem caused by the low effective refractive index difference will make the system signal recovery more difficult

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