CN208015733U - A kind of optical fiber forward pass system based on modal sets multiplexing - Google Patents

Abstract

Present patent application proposes a kind of optical fiber forward pass system being multiplexed based on modal sets；The system can provide the quad capacity of single mode optical fiber Transmission system；Or the optical fiber forward pass transmission pressure on capacity or rate is reduced to a quarter of single mode optical fiber Transmission system；System poor, four modal sets less fundamental mode optical fibre of large effective area using big effective refractive index, effectively reduces nonlinear effect and pattern crosstalk；New approaches and guarantee are provided for mobile telecommunication optical fiber forward pass long span transmission under special applications scene.

Description

A kind of optical fiber forward pass system based on modal sets multiplexing

Technical field

Present patent application is related to a kind of optical fiber forward pass system being multiplexed based on modal sets, can be applied to fiber optic communication, optical fiber The fields such as wireless access, optical Information Processing and generation information technology.

Background technology

As data communication is continuously increased with multimedia service demand, mobile communication rapid development simultaneously constantly meets people Communication requirement；However, the front end delivery interface that existing mobile communications network uses is deposited in terms of data rate, bandwidth, time delay In significant limitation；For such case, the units such as China Mobile Communications Research Institute propose next-generation forward pass interface NGFI (Next Generation Front-haul Interface)[1China mobile research institute,et Al.White Paper of Next Generation Fronthaul Interface, v1.0 (2015) ]To meet the 5th The demand of third-generation mobile communication (5G) development；NGFI refers to Base-Band Processing function and far end radio frequency in next generation wireless network main equipment Front-haul forward pass interfaces between processing function, provide five kinds of interface splitting schemes, analogue transmission not only may be used, but also Digital transmission technology can be used to reduce to system parameter requirement, can flexibly accept or reject, be mobile communication Front-haul forward pass nets The further research of network provides important references.In recent years, wireless cloud center (RCC, the radio cloud in NGFI Center) the high speed of the Front-haul optical fiber transmission between far end radio frequency system (RRS, radio remote system) Rate, high power capacity, long span demand increasingly increase severely.Meanwhile as wireless multiple-input, multiple-output (MIMO) technology is wireless in 4G, 5G and future Application in communication has been further exacerbated by optical fiber forward pass transmission Ya Li [2X.Liu,H.Zeng,N.Chand,andF. Effenberger,"Bandwidth-Efficient Mobile Fronthaul Transmission for Future 5G Wireless Networks,"in Asia Communications and Photonics Conference 2015,C.Lu, J.Luo,Y.Ji,K.Kitayama,H.Tam,K.Xu,P.Ghiggino,and N.Wada,eds.,OSA Technical Digest(Optical Society of America,2015),paper ASu3E.4]；Certainly, current conventional radio MIMO Technical research outputs and inputs Shuo Mu &#91 also in less;3Chi-Hsiang Lin, Chun-Ting Lin,Hou-Tzu Huang,Wei-Siang Zeng,Shou-Chih Chiang,and Hsi-Yu Chang,"60-GHz optical/ wireless MIMO system integrated with optical subcarrier multiplexing and 2x2wireless communication,"Opt.Express 23,12111-12116 (2015)]；Extensive mimo antenna Research also also in strategic concept and preliminarily theoretical simulation stage, really deployment and realize that it is still necessary to want the long period [4E.Larsson,O.Edfors,F.Tufvesson,T. Marzetta,“Massive MIMO for next generation wireless systems,”IEEE Communications Magazine,52(2):186-195 (2014)；5L.Lu,G.Y.Li,A.L. Swindlehurst,A.Ashikhmin,R.Zhang,"AnOverview ofMassive MIMO:Benefits and Challenges,”IEEE Journal of Selected Topics in Signal Processing,8(5): 742-758(2014)；6J.Shen,S.Suyama,T.Obara,Y.Okumura, “Requirements of power amplifier on super high bit rate massive MIMO OFDM transmission using higher frequency bands,”Globecom Workshops(GC Wkshps), 2014:433-437].In this way, current urgent communication requirement and MIMO technology bring optical fiber forward pass on capacity and rate Immense pressure, although can exponentially reduce transmission rate by filtering and compressing, still to Front-haul optical transport networks Great pressure is caused, is a Ju great Tiao Zhan &#91 to the following optical fiber forward pass;1；7Yiran Ma, ZhiguangXu, Chengliang Zhang,Huafeng Lin,Qing Wang,Min Zhou,Heng Wang, Jingwen Yu,and Xiaomu Wang,"Demonstration of digital fronthaul over self-seeded WDM-PON in commercial LTE environment,"Opt.Express 23,11927-11935 (2015)；8Y.Ma,Z.Xu, H.Lin,M.Zhou,H.Wang,C.Zhang,J.Yu,andX.Wang, "Demonstration of CPRI over Self- seeded WDM-PON in Commercial LTE Environment,"in Optical Fiber Communication Conference,OSA Technical Digest(Optical Society of America,2015),paper M2J.6； 9M.Zhu,X.Liu,N. Chand,F.Effenberger,and G.Chang,"High-Capacity Mobile Fronthaul Supporting LTE-Advanced Carrier Aggregation and 8×8MIMO,"in Optical Fiber Communication Conference,OSA Technical Digest(Optical Society of America, 2015),paper M2J.3]。

Meanwhile mode multiplexing (MDM) technology is to regard each spatial model in less fundamental mode optical fibre (FMF) as parallel transmission Subchannel is exactly natural multiple-input and multiple-output (MIMO) system in the MDM system natures based on FMF；Based on FMF's MDM technologies have become the forward position research hotspot of optical communication field, are field ultrahigh speed, vast capacity, extra long distance, the Gao Pu Effect transmits most potential one of realization method, has extremely wide Ying Yongqianjinghefazhankongjian [10He Wen, Hongjun Zheng,Qi Mo, et al.Few-Mode Fibre-Optic Microwave Photonic Links, Light:Science& Applications,2017.8,6,e17021,1-8；11Bin Huang,Nicolas K.Fontaine,Roland Ryf, Binbin Guan,Sergio G.Leon-Saval,R.Shubochkin,Y.Sun, R.Lingle,and Guifang Li,"All-fiber mode-group-selective photonic lantern using graded-index multimode fibers,"Opt.Express 23,224-234(2015)].Normal conditions Under, intercoupling between degenerate mode in less fundamental mode optical fibre, slightly strong, pattern crosstalk is slightly larger, and receiving terminal degenerate mode data processing difficulty is slightly Greatly.

Utility model content

In view of the above-mentioned problems, in state natural sciences fund (number 61671227 and 61431009), nature section of Shandong Province Under NSF National Science Foundation (ZR2011FM015), " Mount Taishan scholar " construction project specific project expenditure are supported, present patent application proposes one kind and is based on The optical fiber forward pass system of modal sets multiplexing；Present patent application modal sets multiplexing method is that the degenerate mode in same modal sets is only adopted Signal is transmitted with one of pattern, and different degenerate modes transmits identical letter during another pattern is spare or same modal sets Number；In this way, effective refractive index difference reforms into the effective refractive index between larger modal sets between the corresponding pattern of difference transmission signal Difference, pattern crosstalk effectively reduce；The Transmission system that present patent application is proposed often increases one mode group signal, and optical fiber forward pass passes Defeated capacity is doubled than single-mode system；It is capable of providing more multiplication capacity of multiple identical as modal sets number；Effectively solve Optical fiber forward pass is mobile logical under special applications scene in facing challenges such as capacity, rate, spectrum efficiency, lower deployment cost demands Believe that the transmission of optical fiber forward pass long span provides new approaches and guarantee.

Technical solution is used by present patent application solves its technical problem：

For the active demand of mobile telecommunication optical fiber forward pass transmission capacity under special applications scene, present patent application proposes A kind of optical fiber forward pass system based on modal sets multiplexing；The system includes that wireless cloud center RRC, fiber transmission link and radio frequency are drawn Remote system RRS；Wherein, wireless cloud center RRC specifically includes RRC Base-Band Processings end and the ports NGFI, Polarization Controller and pattern The alternative photon lantern of group；Fiber transmission link is four modal sets less fundamental mode optical fibre transmission links；Radio frequency stretch system RRS includes Modal sets alternative photon lantern, four enter four and go out photodetection and data and radio frequency processing module, antenna transmitting module；RRC Base-Band Processing end is connected to four single mode ends of modal sets alternative photon lantern, mould with the ports NGFI through Polarization Controller Formula group alternative photon lantern taper lacks mould end and is fused to that one big effective refractive index is poor, four modal sets of large effective area lack mould Fiber transmission link；The taper that less fundamental mode optical fibre transmission link output end is connected to modal sets alternative photon lantern lacks mould end, Four single mode ends of modal sets alternative photon lantern, which are connected respectively to four and enter four, goes out photodetection and data and radio frequency processing Four input terminals of module；Four, which enter four, goes out photodetection and data and four output ends of radio frequency processing module are connected to four n × n radio MIMO antenna transmitting modules；RRC Base-Band Processings end and the ports NGFI export four phase co-wavelengths or close to wavelength Or the signal of different wave length is respectively through Polarization Controller single mode transport to four patterns of modal sets alternative photon lantern Group single mode end lacks the implementation pattern conversion of mould end and multiplexing in photon lantern, is multiplexed into four modal sets signal all the way；Four modal sets By one big effective refractive index, poor, four modal sets less fundamental mode optical fibre transmission link of large effective area transmits signal；And then enter In radio frequency stretch system RRS；Four modal sets signal modes are converted by modal sets alternative photon lantern and are demultiplexing as four Road single mode signal, each modal sets signal correspond to single mode signal all the way；Later, demultiplexing tetra- road single mode signals of Hou enter four through four Go out after photodetection and data and radio frequency processing module processing to be respectively outputted to four n × n radio MIMO antenna transmitting modules into Row transmitting；Each n × n radio MIMO antennas transmitting module (n=1,2,3,256), corresponding 1 wired input end and N transmitting antenna；Each n × n radio MIMO antenna transmitting modules have the function of independent transmission and joint emission function；Four n × n radio MIMO antenna transmitting modules may make up whole 4n × 4n radio MIMOs antenna emitting portion using joint emission function； If n=1, antenna can be integrally formed the emitting portion of 4 × 4 radio MIMO antennas；If n=2, it is wireless that antenna can be integrally formed 8 × 8 The emitting portion of mimo antenna.

The advantageous effect of present patent application is：

1. the system that present patent application is proposed often increases one mode group signal, optical fiber forward pass transmission capacity compares single-mode optics Fine Transmission system doubles, and can be increased to four times of transmission capacities；If each modal sets signal is kept to be passed with single mode optical fiber Defeated system equivalent data rates capacity can improve the diversity gain of radio MIMO antenna or spatial multiplexing gain or both EQ Gain To four times；Under identical antenna channel capacity situation, the optical fiber of system that present patent application is proposed on capacity or rate Forward pass transmission pressure is reduced to a quarter of single mode optical fiber Transmission system；

2. system poor, four modal sets less fundamental mode optical fibre of large effective area using big effective refractive index, effectively reduces non-linear effect It should be with pattern crosstalk；

3. correspondence system is transmitted using the close either phase co-wavelength of wavelength or different wave length, to swashing in system Light device, photoelectric detection module performance are not strict with, and system complexity and cost can be effectively reduced；

It is special 4. the Transmission system transmission capacity of present patent application proposition is big, rate and the availability of frequency spectrum are high, at low cost Mobile telecommunication optical fiber forward pass provides new approaches and guarantee under application scenarios.

Description of the drawings

Fig. 1 is a kind of optical fiber forward pass system schematic being multiplexed based on modal sets of present patent application.

Fig. 2 is modal sets alternative photon lantern schematic diagram；

Fig. 3 is less fundamental mode optical fibre cross-sectional view；

Wherein, the modal sets alternative photon lantern in present patent application Fig. 2, Fig. 3 and less fundamental mode optical fibre are using our classes Topic group Xiang Guanlunwen [10He Wen,Hongjun Zheng,Qi Mo,et al.Few-Mode Fibre-Optic Microwave Photonic Links,Light:Science&Applications,2017.8,6,e17021,1-8]In make Modal sets alternative photon lantern and less fundamental mode optical fibre.

Specific implementation mode

The technical solution of the utility model patent application is described in detail with reference to embodiment and attached drawing, but protection domain is not It is limited to this.

1 Fig. 1 of embodiment is a kind of optical fiber forward pass system schematic being multiplexed based on modal sets of present patent application.The system point For 3 function modules：1 is wireless cloud center RRC, and 2 be fiber transmission link, and 3 be radio frequency stretch system RRS；Wherein, wireless cloud Center RRC includes RRC Base-Band Processings end and the Polarization Controller 2,3,4,5 of the ports NGFI 1, four and modal sets alternative photon Lantern 6；Fiber transmission link is four modal sets less fundamental mode optical fibre transmission links 7；Radio frequency stretch system RRS includes that modal sets may be selected Property photon lantern 6, four enter four and go out photodetection and data and 9, four n × n radio MIMO antennas transmitting moulds of radio frequency processing module Block 10,11,12,13；RRC Base-Band Processings end is connected to modal sets through Polarization Controller 2,3,4,5 with the ports NGFI 1 and may be selected Property photon lantern 6 four single mode ends, 6 taper of modal sets alternative photon lantern lacks mould end and is fused to one big effectively folding Penetrate that rate is poor, four modal sets less fundamental mode optical fibre transmission link 7 of large effective area；7 output end of less fundamental mode optical fibre transmission link is connected to pattern The taper of group alternative photon lantern 6 lacks mould end, and four single mode ends of modal sets alternative photon lantern 6 are connected respectively to Four enter four four input terminals for going out photodetection and data and radio frequency processing module 9；Four, which enter four, goes out photodetection and data and penetrates Four output ends of frequency processing module 9 are connected to four n × n radio MIMO antennas transmitting modules 10,11,12,13；RRC bases Tape handling end exports four phase co-wavelengths with the ports NGFI 1 and is either controlled respectively through polarization close to the signal of wavelength or different wave length 2,3,4,5 single mode transport of device processed may be selected to four modal sets single mode ends of modal sets alternative photon lantern 6 in modal sets Property the few mould end implementation pattern conversion of photon lantern 6 and multiplexing, be multiplexed into four modal sets signal all the way；This four modal sets transmits signal It is LP01, LP11a (or LP11b), LP21a (or LP21b) and LP02 signals respectively；The four modal sets signal is big by one Effective refractive index is poor, four modal sets less fundamental mode optical fibre transmission link 7 of large effective area transmits；And then enter radio frequency stretch system In RRS；Four modal sets signal modes are converted by modal sets alternative photon lantern 6 and are demultiplexing as four road single mode signals, Each modal sets signal corresponds to single mode signal all the way；Later, demultiplexing tetra- road single mode signals of Hou enter four through four and go out photodetection And it is respectively outputted to four n × n radio MIMO antennas transmitting modules 10,11,12,13 after data and the processing of radio frequency processing module 9 Emitted；Each n × n radio MIMO antennas transmitting module (n=1,2,3,256) and, corresponding 1 wired input end With n transmitting antenna；Each n × n radio MIMO antenna transmitting modules have the function of independent transmission and joint emission function；Four A n × n radio MIMOs antenna transmitting module may make up whole 4n × 4n radio MIMOs antenna emission part using joint emission function Point；If n=1, antenna can be integrally formed the emitting portion of 4 × 4 radio MIMO antennas；If n=2, antenna can be integrally formed 8 × 8 The emitting portion of radio MIMO antenna.

Fig. 2 is modal sets alternative photon lantern schematic diagram；In figure, centre is one section of less fundamental mode optical fibre, the right and left point It is not photon lantern；The taper of photon lantern lacks the intermediate less fundamental mode optical fibre of mould end connection；The leftmost side and the rightmost side are photons in figure Lantern single mode end；Photon lantern pattern LP01 corresponds to the optical fiber that input terminal is 22 μm of core diameter, and LP11a and LP11b correspond to defeated Enter the optical fiber that end is 20 μm of core diameter, LP21a, LP21b and LP02 correspond to the optical fiber that input terminal is 15 μm of core diameter [11]；Routine is in application, six single mode optical fibers are fused to six single mode ends of modal sets alternative photon lantern, photon respectively Lantern lacks mould end and is fused to a less fundamental mode optical fibre；In this way, four single mode signals of input can be converted respectively by photon lantern It is multiplexed into less fundamental mode optical fibre, modal sets all the way is formed and transmits signal；Wen Xian [11]In these modal sets transmission signal be first respectively Modal sets LP01, second mode group LP11a and LP11b, the third mode group LP21a, LP21b and LP02.Wen Xian [10]Study table It is bright, although refringence is smaller between pattern LP21 and LP02, not degeneracy；And in the case of less fundamental mode optical fibre transmission perturbation；Pattern It is not coupled between LP21 and LP02.

In this way, present patent application application in, by the output mode group of the photon lantern be classified as first mode group LP01, Second mode group LP11a and LP11b, the third mode group LP21a and LP21b, fourth mode group LP02；The photon lantern is special at this Then it is known as modal sets alternative photon lantern in profit application；Degenerate mode in same modal sets is only with one of pattern Transmit signal, different degenerate modes transmits identical signal during another pattern is spare or same modal sets.Four single-mode optics Fibre is fused to four modal sets single mode ends of photon lantern respectively, and photon lantern, which lacks mould end and is fused to four modal sets, lacks mould light It is fine；Four single mode signals of input can be converted respectively by photon lantern and be multiplexed into less fundamental mode optical fibre, form four modal sets all the way Transmit signal；This four modal sets transmission signal is LP01, LP11a (or LP11b), LP21a (or LP21b) and LP02 letters respectively Number；If signal negative direction transmits, four modal sets all the way of input can be transmitted by photon lantern by signal conversion and be demultiplexed into four Single mode optical fiber forms four single mode transport signals.Modal sets alternative photon lantern 6 in the RRC of wireless cloud center is used as Modal sets are converted and multiplexing, and the modal sets alternative photon lantern 6 in radio frequency stretch system RRS is used as modal sets and converts and solve Multiplexing.It also can be Wen Xian [10]Middle pattern alternative photon lantern sorts out processing according to above-mentioned modal sets and is applied to this patent Shen Please in.

Fig. 3 is less fundamental mode optical fibre cross-sectional view；In Fig. 3, white portion is fibre core, and right tiltedly dash area is refractive index groove, Left tiltedly dash area is the protrusion in refractive index groove, and it is fibre core covering to erect oblique dash area.The less fundamental mode optical fibre is big effectively folding Penetrate that rate is poor, six pattern less fundamental mode optical fibre of large effective area；Sort out processing method according to above-mentioned photon lantern modal sets, six pattern is few The pattern transmission signal of mode fiber is first mode group LP01, second mode group LP11a and LP11b, the third mode group respectively LP21a and LP21b, fourth mode group LP02；In the present patent application, which is known as four modal sets and lacks mould light It is fine；It is LP01, LP11a (or LP11b), LP21a (or LP21b) and LP02 signals respectively that this four modal sets, which transmits signal,.This is few Effective refractive index difference reaches 10 between mode fiber modal sets^-3Magnitude, effective area are 1.6 times of standard single-mode fiber, 1550 waves Section minimal attenuation coefficient is the 0.227dB/km of LP01 patterns, and maximum attenuation coefficient is the 0.262dB/km of LP02 patterns；No Pattern crosstalk very little can be obtained with the response of modal sets signal pulse；Its multichannel nonlinear crosstalk also Hen little [10].

In short, present patent application proposes a kind of optical fiber forward pass system being multiplexed based on modal sets；System is connect using wavelength Closely either phase co-wavelength or different wave length are transmitted, not tight to the laser in system, photoelectric detection module performance The requirement of lattice can substantially reduce system complexity and cost；System poor, four modal sets of large effective area using big effective refractive index Less fundamental mode optical fibre effectively reduces nonlinear effect and pattern crosstalk；Use Polarization Controller to adjust signal state of polarization with into one simultaneously Walk reduction pattern crosstalk；Using photon lantern implementation pattern group conversion multiplexing and modal sets conversion demultiplexing, loss is effectively reduced, System power budget is improved, extend transmission distance and increases accessing user's quantity；The system that present patent application is proposed often increases Add one mode group signal, optical fiber forward pass transmission capacity to be doubled than single mode optical fiber Transmission system, four times can be increased to Transmission capacity；It, can be radio MIMO if keeping each modal sets signal and single mode optical fiber Transmission system equivalent data rates capacity The diversity gain or spatial multiplexing gain of antenna or both EQ Gain are increased to four times；Under identical antenna channel capacity situation, Optical fiber forward pass transmission pressure of the system that present patent application is proposed on capacity or rate is reduced to single mode optical fiber Transmission system A quarter；The availability of frequency spectrum improves；Cost-effective reduction；The system that present patent application proposes is that special applications scene moves down Dynamic telecommunication optical fiber forward pass provides new approaches and guarantee.

It should be pointed out that specific implementation mode is the more representational example of present patent application, it is clear that this patent The technical solution of application is not limited to the above embodiments, and can also have many variations.Those skilled in the art, with this patent The obtaining undoubtedly disclosed in application define or according to the written description of file, is considered as claimed by this patent Range.

Claims (1)

1. a kind of optical fiber forward pass system based on modal sets multiplexing, it is characterised in that：The system is divided into wireless cloud center RRC, light Fine transmission link and radio frequency stretch system RRS totally three function modules；Wireless cloud center RRC include RRC Base-Band Processings end with The ports NGFI (1), four Polarization Controllers (2) (3) (4) (5) and modal sets alternative photon lantern (6)；Optical fiber chain Road is four modal sets less fundamental mode optical fibre transmission links (7)；Radio frequency stretch system RRS include modal sets alternative photon lantern (6), Four, which enter four, goes out photodetection and data and radio frequency processing module (9), four n × n radio MIMO antenna transmitting modules (10) (11) (12)(13)；RRC Base-Band Processings end is connected to modal sets through Polarization Controller (2) (3) (4) (5) with the ports NGFI (1) and may be selected Property photon lantern (6) four single mode ends, modal sets alternative photon lantern (6) taper lack mould end be fused to it is one big effectively Refringence, four modal sets less fundamental mode optical fibre transmission link (7) of large effective area；Less fundamental mode optical fibre transmission link (7) output end connects Taper to modal sets alternative photon lantern (6) lacks mould end, four single mode ends of modal sets alternative photon lantern (6) It is connected respectively to four and enters four four input terminals for going out photodetection and data and radio frequency processing module (9)；Four enter four light extraction electrical resistivity surveys It surveys and four output ends of data and radio frequency processing module (9) is connected to four n × n radio MIMO antenna transmitting modules (10) (11)(12)(13)；RRC Base-Band Processings end exports four phase co-wavelengths either close to wavelength or different waves from the ports NGFI (1) Four respectively through Polarization Controller (2) (3) (4) (5) single mode transport to modal sets alternative photon lantern (6) of long signal The conversion of mould end implementation pattern and multiplexing are lacked in modal sets single mode end in modal sets alternative photon lantern (6), are multiplexed into all the way four Modal sets signal；By one big effective refractive index, poor, four modal sets less fundamental mode optical fibre of large effective area passes the four modal sets signal Transmission link (7) transmits；And then enter in radio frequency stretch system RRS；By modal sets alternative photon lantern (6) four moulds Formula group signal mode is converted and is demultiplexing as four road single mode signals, and each modal sets signal corresponds to single mode signal all the way；Later, it solves Multiplexed four road single mode signal through four enter four go out photodetection and data and radio frequency processing module (9) processing after be respectively outputted to Four n × n radio MIMO antenna transmitting modules (10) (11) (12) (13) are emitted；Each n × n radio MIMO antennas transmitting Module (n=1,2,3,256) and, corresponding 1 wired input end and n transmitting antenna；Each n × n radio MIMO antennas Transmitting module has the function of independent transmission and joint emission function；Four n × n radio MIMO antenna transmitting modules are sent out using joint It penetrates function and may make up whole 4n × 4n radio MIMOs antenna emitting portion；If n=1, antenna can be integrally formed 4 × 4 radio MIMOs The emitting portion of antenna；If n=2, antenna can be integrally formed the emitting portion of 8 × 8 radio MIMO antennas.