CN206788408U - A kind of large effective area mode division multiplexing device - Google Patents

Abstract

It is one of to be used as main transmission channel the utility model proposes a kind of large effective area mode division multiplexing device, including 6 identical transmission channels；The cross section of these transmission channels is made up of pure silicon dioxide matrix blanket and doping silicon dioxide core on the whole；Core external diameter, the cladding outer diameter of the channel are corresponding in turn to 38 μm and 100 μm；Core centre and fibre cladding refractive index are respectively 1.444874 and 1.444024；Channel core center is distributed to the refractive index of covering in gradation type.The utility model realizes graded refractive index distribution, the few mould multiplexing of large effective module scene product, 6 patterns of low nonlinearity coefficient, high coupling efficiency, wide service band, has broad prospect of application in fields such as the few mould transmission of fiber optic communication, the few mould transmission of Front haul.

Description

A kind of large effective area mode division multiplexing device

Technical field

Present patent application is related to a kind of mode division multiplexing structure, and in particular to a kind of large effective area mode division multiplexing device, can answer For fields such as fiber optic communication, optical Information Processings.

Background technology

In recent years, the fiber optic communication research field based on mode division multiplexing is one of forward position focus；As its key technology it One mode division multiplexing device gets the attention [1 Guifang Li, Neng Bai, and Ningbo Zhao and Cen Xia,Space- division multiplexing:the next frontier in optical communication.Advances in Optics&Photonics, 2014,6(4):5041-5046]；Document [2RolRyf,Bolle C A,Hoyningenhuene J V.Optical Coupling Components for Spatial Multiplexing in Multi-Mode[C].European Conference and Exhibition on Optical Communication.2011:1-3；3Li A,Chen X,Alamin A,et al.Space-Division Multiplexed High-Speed Superchannel Transmission Over Few-Mode Fiber[J].Journal of Lightwave Technology,2012,30(24):3953-3964] a kind of mode division multiplexing device based on phase-plate is proposed, Realize three kinds of mode changeover signals and be multiplexed into same channel, but this mode division multiplexing device needs the space of pinpoint accuracy Coupling calibration, and be difficult to integrate, the insertion loss of free space coupling is big, and cost is high.Document [4 Fontaine N K, Ryf R,Leonsaval S G,et al. Evaluation of Photonic Lanterns for Lossless Mode- Multiplexing[C].Optical Communications (ECOC),2012 38th European Conference and Exhibition on.IEEE,2012:1-3；5Ryf R,Fontaine N K,Montoliu M,et al.Photonic-lantern-based mode multiplexers for few-mode-fiber transmission [C].Optical Fiber Communications Conference and Exhibition.IEEE,2014:1-3；6 Leonsaval S G,Fontaine N K,Salazargil J R,et al.Mode-selective photonic lanterns for space- division multiplexing[J].Optics Express,2014,22(1):1036- 44.] a kind of " photon lantern " mode division multiplexing device for drawing cone-shaped is proposed, realize 12 road mode changeover signals and be multiplexed into same One channel." photon lantern " although complex degree of structure it is lower than space coupler, its manufacturing process is accurate, complicated, Position, drawing cone thickness and length when accurately controlling fiber fuse have great difficulty；By draw taper into output end Mouth and transmission channel Incomplete matching, can cause high loss.[7 stones are good for the mode division multiplexing communication technologys of the based on less fundamental mode optical fibre to document Research [D] Jilin University, 2013] mode division multiplexing/demultiplexer based on asymmetric slab guide is devised, realize pattern Multiplexing, demultiplexing, also achieve the conversion of pattern；But service band to be present narrow for the plane multiplexer, it is difficult to it is integrated, with The problem of fused fiber splice difficulty.Document [8 Huang B, 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.IEEE,2013:1-3；9Xie Y,Fu S,Liu H,et al.Design and numerical optimization of a mode multiplexer based on few-mode fiber couplers [J].Journal of Optics,2013, 15(12):3901-3901；10Tsekrekos C P,Syvridis D.Symmetric Few-Mode Fiber Couplers as the Key Component for Broadband Mode Multiplexing[J].Journal of Lightwave Technology,2014, 32(14):2461-2467.] in set The direct-coupled multiplexer of pattern is counted；The multiplexer manufacturing process is simple, directly and fused fiber splice can have wider work Wave band；But the multiplexer is designed without consideration transmission channel nonlinear problem；As the mode division multiplexing device of less fundamental mode optical fibre, The problems such as needing to consider large effective area, the low nonlinearity coefficient of its transmission channel.

Utility model content

In state natural sciences fund (numbering 61671227 and 61431009), Shandong Province's Natural Science Fund In The Light (ZR2011FM015) under, " Mount Taishan scholar " construction project specific project expenditure is supported, this patent proposes a kind of large effective area mould point Multiplexer, realize graded refractive index distribution, large effective module scene product, low nonlinearity coefficient, high coupling efficiency, wide operating wave The few mould multiplexing of 6 patterns of section；For the few mould transmission of fiber optic communication, the few mould transmission of Front-haul is practical provides support.

The technical scheme of the present utility model that specifically uses is as follows：

A kind of large effective area mode division multiplexing device that this patent proposes, including 6 identical transmission channels, it is one of to make For main transmission channel；The cross section of these transmission channels is by pure silicon dioxide matrix blanket and doping silicon dioxide core on the whole Composition；Core external diameter, the cladding outer diameter of the channel are corresponding in turn to 38 μm and 100 μm；Fiber core radius is balanced with index distribution to be set Meter；Core centre and fibre cladding refractive index are respectively 1.444874 and 1.444024；Refractive index of the channel core center to covering It is distributed in gradation type；Refractive index is according to equation

Set, n in formula₁Represent core centre refractive index, n₂Cladding index is represented, r represents fiber radius, a=R1=38 μm it is fiber core external diameter,The position of each channel of multiplexer and length aspect, Pattern LP₀₂Main transmission channel is directly inputted, to avoid pattern LP₀₂Coupling process caused by channel couples efficiency is too low was lost Greatly；Pattern LP_11bAnd LP_21bChannel is placed on main transmission channel cross section x directions, channel length be respectively 362mm and 325mm, the spacing with main channel are 5 μm；Pattern LP₀₁、LP_11aAnd LP_21aChannel is placed in y-direction, channel length difference For 5651mm, 362mm and 1882mm, the spacing with main channel is respectively 5 μm, 5 μm and 32 μm, ensures to be multiplexed by arrangement above The superperformance of device.Few mould multiplexer characteristic is studied using full-vector finite element method and beam propagation method.

The beneficial effects of the utility model are as follows：

1. the mode division multiplexing device proposed realizes graded refractive index distribution, large effective module scene product, low nonlinearity system The few mould multiplexing of number, high coupling efficiency, 6 patterns of wide service band；

2. in C-band, the channel couples efficiency of multiplexer either mode is better than -0.112dB, and flat spy well is presented Property；

3. it is wide that the multiplexer characteristic makes it have in fields such as the few mould transmission of fiber optic communication, the few mould transmission of Front-haul Application prospect.

Brief description of the drawings

Fig. 1 is a kind of single channel cross-sectional view of large effective area mode division multiplexing device；R1 is core external diameter in figure, R2 For cladding outer diameter；

Fig. 2 is a kind of channel effective area of large effective area mode division multiplexing device and nonlinear factor with lambda1-wavelength Variation diagram；Solid line difference intermediate scheme LP with right triangle, asterisk, circle number and period in Fig. 2 (a)₀₁、LP₁₁、LP₂₁And LP₀₂'s Effective core area with lambda1-wavelength change；Solid line with right triangle, asterisk, circle number and period in Fig. 2 (b) represents respectively Pattern LP₀₁、LP₁₁、LP₂₁And LP₀₂Nonlinear factor with lambda1-wavelength change；

Fig. 3 is proposed mode division multiplexing device structural representation；Fig. 3 (a) is overall structure diagram, and Fig. 3 (b) is in master The schematic diagram in transmission channel cross section x directions, Fig. 3 (c) are the schematic diagrames in y directions；

Fig. 4 is variation diagram of the various mode channel coupling efficiencies of mode division multiplexing device with lambda1-wavelength, the band right side three in Fig. 4 Angle, asterisk, four square frames, circle and left triangle solid line difference intermediate scheme LP₀₁、LP_11a、LP_11b、LP_21aAnd LP_21bCoupling efficiency with The change of lambda1-wavelength.

Embodiment

The technical solution of the utility model, but protection domain not limited to this are described in detail with reference to embodiment and accompanying drawing.

The Fig. 1 of embodiment 1 is a kind of single channel cross-sectional view of large effective area mode division multiplexing device of this patent, the multiplexing Device single channel cross section is made up of pure silicon dioxide matrix blanket and doping silicon dioxide core on the whole；Each radius of circle in figure R1 and R2 are expressed as, is corresponding in turn to core external diameter, cladding outer diameter, wherein, R1=38 μm and R2=100 μm.Channel core radius With index distribution Equalization Design；Channel covering and core refractive index of the centre are respectively 1.444024 and 1.444874；In channel core The refractive index of the heart to covering changes in gradation type.Refractive index is according to equation

Set, n in formula₁Represent core centre refractive index, n₂Cladding index is represented, r represents fiber radius, a=R1=38 μm it is fiber core external diameter,Using full-vector finite element method and beam propagation Method have studied the characteristic of the mode division multiplexing device.

Fig. 2 is a kind of channel effective area of large effective area mode division multiplexing device of this patent and nonlinear factor with incident light The change of wavelength, the solid line difference intermediate scheme LP with right triangle, asterisk, circle number and period in Fig. 2 (a)₀₁、LP₁₁、LP₂₁With LP₀₂Effective core area with lambda1-wavelength change；Solid line point with right triangle, asterisk, circle number and period in Fig. 2 (b) Other intermediate scheme LP₀₁、LP₁₁、LP₂₁And LP₀₂Nonlinear factor with lambda1-wavelength change.Can be with by Fig. 2 (a) and 2 (b) To find out, corresponding 1450nm to 1650nm wave-length coverages, the effective area of four kinds of patterns increases with the increase of lambda1-wavelength, and four The effective area of kind pattern is all much larger than standard single-mode fiber；Corresponding given input wavelength, pattern LP₀₁、LP₁₁、 LP₂₁With LP₀₂Effective area increase successively；And the nonlinear factor of four kinds of patterns reduces with the increase of wavelength, nonlinear factor is all very It is small；Corresponding given input wavelength, pattern LP₀₁、LP₁₁、LP₂₁And LP₀₂Nonlinear factor be sequentially reduced；In 1550nm wave bands, The effective core area of each pattern is both greater than 80 μm of standard single-mode fiber²More than 15 times；Its nonlinear factor is much smaller than standard The nonlinear factor of single-mode fiber.No differentiation LP discussed above₁₁And LP₂₁Merger pattern, be because these merger patterns have It is consistent with Electric Field Distribution to imitate refractive index, causes merger pattern effective core area and nonlinear factor closely similar；But two letters When road carries out Mode Coupling, annexing modal phase difference causes coupled characteristic different, therefore merger pattern makes a distinction discussion below.

The relation of comprehensive study channel spacing, channel length and coupling efficiency, this patent propose multiplexer as shown in Figure 3 Structure, Fig. 3 are the structural representations in the overall structure (a) of multiplexer, main transmission channel cross section x directions (b) and y directions (c). The multiplexer is made up of 6 identical transmission channels, and one of them is main transmission channel.Consider mode channel coupling length Degree, channel separation and coupling efficiency situation of change, pattern LP₀₂Main transmission channel is directly inputted, to avoid pattern LP₀₂Channel Coupling process loss is excessive caused by coupling efficiency is too low；Pattern LP_11bAnd LP_21bChannel is placed on main transmission channel cross section x On direction, channel length is respectively 362mm and 325mm, and the spacing with main channel is 5 μm；Pattern LP₀₁、 LP_11aAnd LP_21aLetter Road is placed in y-direction, and channel length is respectively 5651mm, 362mm and 1882mm, and the spacing with main channel is respectively 5 μm, 5 μ M and 32 μm, the high coupling efficiency of multiplexer and reasonable coupling length are ensured by arrangement above.

Fig. 4 is change of the various mode channel coupling efficiencies of mode division multiplexing device with lambda1-wavelength, in Fig. 4 with right triangle, Asterisk, four square frames, circle and left triangle solid line difference intermediate scheme LP₀₁、LP_11a、LP_11b、LP_21aAnd LP_21bCoupling efficiency is with entering Penetrate the change (corresponding C-band situation) of optical wavelength.Pattern LP₀₂Main transmission channel is directly inputted, therefore only considers other 5 kinds of patterns Coupling efficiency.It can be obtained by Fig. 4, in C-band, for 5 kinds of all patterns, the maximum of any one mode coupling efficiency It is no more than 0.066dB with minimum value difference, coupling efficiency shows good flat characteristic；Pattern LP₀₁、 LP_11a、LP_11bAnd LP_21b Average coupling efficiency be 0dB, pattern LP_21aAverage coupling efficiency be -0.112dB, better than document [10] in C-band The pattern LP that horizontal and vertical polarization direction is realized₀₁、LP_11a、LP_11b、LP_21a、LP_21bAnd LP₀₂Average coupling efficiency- 0.4dB, -1.69dB, -0.82dB, -4.07dB, -1.99dB and -0.17.

In a word, this patent propose large effective area mode division multiplexing device realize mode channel graded refractive index distribution, Large effective area, small nonlinear factor, high coupling efficiency, wide service band characteristic；In C-band, multiplexer either mode Coupling efficiency is better than -0.112dB, and good flat characteristic is presented.This further research to mode division multiplexing device has important meaning Justice, which is the few mould transmission of fiber optic communication, the few mould transmission of Front-haul is practical provides support.

Claims (1)

1. a kind of large effective area mode division multiplexing device, it is characterized in that, including 6 identical transmission channels, it is one of as master Transmission channel；The position of each mode channel of multiplexer and length aspect, pattern LP₀₂Directly input main transmission channel；To avoid mould Formula LP₀₂Coupling process loss is excessive caused by channel couples efficiency is too low；Pattern LP_11bAnd LP_21bChannel is placed on main transmission letter On the x directions of road cross section, channel length is respectively 362mm and 325mm, and the spacing with main channel is 5 μm；Pattern LP₀₁、LP_11a And LP_21aChannel is placed in y-direction, and channel length is respectively 5651mm, 362mm and 1882mm, is distinguished with the spacing of main channel For 5 μm, 5 μm and 32 μm；The cross section of these transmission channels is by pure silicon dioxide matrix blanket and doping titanium dioxide on the whole Silicon core forms；Core external diameter, the cladding outer diameter of the channel are corresponding in turn to 38 μm and 100 μm；Core centre and fibre cladding refraction Rate is respectively 1.444874 and 1.444024；Channel core center is distributed to the refractive index of covering in gradation type；Refractive index is according to side Journey

Set, n in formula₁Represent core centre refractive index, n₂Cladding index is represented, r represents fiber radius, and a=R1=38 μm is Fiber core external diameter,