Incoherent chirp-encoding optical CDMA access system

A code division multiple access, coded optical technology, applied in transmission systems, electromagnetic wave transmission systems, optics, etc., can solve the problems of difficult system implementation, immature coherent optical signal processing and transmission technology, etc., and achieve a simple system structure. , low cost, easy to achieve effect

Inactive Publication Date: 2005-02-02
SHANGHAI JIAO TONG UNIV
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Problems solved by technology

At present, the research on bipolar OCDMA adopts the method of coherent coding, but the signal processing and transmission technology of coherent light is not very mature, and the realization of the system is relatively difficult

Method used

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  • Incoherent chirp-encoding optical CDMA access system
  • Incoherent chirp-encoding optical CDMA access system
  • Incoherent chirp-encoding optical CDMA access system

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Embodiment Construction

[0017] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings.

[0018] Such as figure 1As shown in (a), the chirp-coded optical encoder consists of an ultrashort pulse laser source 1, a 1:2 optical splitter 2, and a 1:ω 1 and 1:ω 2 Optical splitter 3, ω 1 +ω 2 a fiber delay line 4, ω 1 : 1 and ω 2 :1 optical combiner 5, two optical circulators 6, one linearly chirped fiber grating 7, and 2:1 optical combiner 8. Among them, ω 1 , ω 2 are the number of positive chirped pulses and negative chirped pulses in the encoding sequence, ω 1 +ω 2 =N, N is the code length. The relative length of the fiber delay line is cT c / n eff Multiples of , and the relative lengths of all fiber delay lines are different, and a continuous non-overlapping pulse sequence can be formed after the final combination. The ultrashort pulse light source 1 emits broadband ultrashort pulses in the form of On / Off keying (or pulse...

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Abstract

The present invention is one incoherent chirp-encoding optical CDMA access system. The optical encoder consists of linear chirp fiber grating, optical circulator, fiber delay line network and optical synthesizer. The data bit modulating ultrashort pulse laser outputs wideband ultrashort optical pulses, which are shunted in a shunt and passed through separate fiber delay line to form two ultrashort pulse sequences. After passing through two optical circulators and chirp fiber grating, two expanded pulse sequences are synthesized into one bipolar chirp-encoded frequency expanding signal. Via a similar process in the optical decoder, one decoded strong output pulse is formed. The present invention has complete fiber structure of coder, and is easy to be integrated, great in system capacity and low in code error rate.

Description

technical field [0001] The invention relates to a new type of non-coherent chirp coding optical code division multiple access system, which can realize multiple access by using bipolar coding in radio frequency CDMA system, and can be used in metropolitan area network, access network, local area network, etc. The system belongs to the technical field of optical fiber communication. Background technique [0002] With the rapid development of optical fiber communication technology, the backbone network has basically realized optical fiber, and the transmission capacity of the system has greatly increased. However, with the rapid growth of business volume and the development of new data services, the metropolitan area network and access network cannot meet The requirements of the development of communication technology have become the bottleneck of the network, and introducing optical fiber into the metropolitan area network and access network has become the best solution to th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02F2/00H04B10/25H04B10/516
Inventor 沈成彬范戈
Owner SHANGHAI JIAO TONG UNIV
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