Low-loss and low-crosstalk gradient refractive index distribution three-mode modulus division multiplexer

Abstract

The invention provides a low-loss and low-crosstalk gradient refractive index distribution three-mode modulus division multiplexer. The low-loss and low-crosstalk gradient refractive index distribution three-mode modulus division multiplexer is composed of three same transmission channels, wherein one transmission channel is a main transmission channel; the radius of each transmission channel is 20mu m; the refractive index difference between a fiber core and a cladding layer of each transmission channel is 0.0015 and the refractive index of the cladding layer is 1.442524; the refractive indexfrom the central of each channel core to the corresponding cladding layer is changed in a gradient manner; a mode LP01 is directly input into the main transmission channel; mode LP11a and LP11b channels are arranged in x and y directions of the cross section of the main transmission channel; the length of each channel is 33mm and the distance between each channel and the main channel is 6mu m; the coupling efficiency of the multiplexer is better than -0.479dB in a wave range of 1400nm to 1700nm; the refractive index gradient change type distribution, low-loss and low-crosstalk three-mode modulus division multiplexing is realized.

Description

Technical field [0001] The invention relates to a mode division multiplexing structure, in particular to a low-loss and low-crosstalk graded refractive index distribution three-mode mode division multiplexer, which can be applied to the new generation of 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 Fibre-Optic Microwave Photonic Links,Light: Science & Applications, 2017.8, 6, e17021, 1-8]; As a key technical link of the Modular 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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