Optical CDMA wavelength-time domain two-dimensional optical orthogonal code coder and decoder

A technology of optical code division multiple access and optical orthogonal code, which is applied in the structural field of encoders and decoders, can solve the problems of inability to realize point-to-multipoint or broadcast communication, large application limitations, and inability to realize networking, etc. problem, to achieve the effect of low cost, effective utilization and wide application value

Inactive Publication Date: 2005-01-26
PEKING UNIV
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AI Technical Summary

Problems solved by technology

As for the wavelength-time domain two-dimensional optical encoder / decoder, only fixed optical encoders / decoders and encoders / decoders with a very limited adjustable range are proposed in the current literature. Using fixed optical encoders / decoders can only achieve point-to-point Point-to-point communication, point-to-multipoint or broadcast communication, and multi-point-to-multipoint communication cannot be realized, and networking cannot be realized
Regarding the dimmable coder / decoder, there are only reports on the use of gratings to realize dimmable coder / decoders. It can only be adjusted in one dimension, and the adjustable range is narrow, and the grating is easily affected by environmental factors such as temperature. The stability of its performance is poor, and its application is very limited.

Method used

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  • Optical CDMA wavelength-time domain two-dimensional optical orthogonal code coder and decoder
  • Optical CDMA wavelength-time domain two-dimensional optical orthogonal code coder and decoder
  • Optical CDMA wavelength-time domain two-dimensional optical orthogonal code coder and decoder

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Embodiment Construction

[0058] Such as image 3 As shown, it is a structural schematic diagram of an example of the optical code division multiple access adjustable two-dimensional optical encoder structure of the present invention, and the encoder can realize a (5×28,4,0,1) optical orthogonal code encoding / decoding. The number of wavelengths of the code is N=5, the number of time cuts M=28, the code weight w=4, and the autocorrelation limit λ a = 0, cross-correlation limit λ c =1. The codeword blocks of this code are:

[0059] [(i 1 , j 1 ), (i 2 , j 2 ), (i 3 , j 3 ), (i 4 , j 4 )]={[(l, (l 7 i 2 )4), (l1, 1+((l1)□ 7 i 2 )4),

[0060] (l4, 2+((l4)□ 7 i 2 )4), (l3, 3+((l3)□ 7 i 2 )4)]: l ∈ [0, 4], i 2 ∈[0,6]}

[0061] Among them,  represents modulo 5 plus, □ 7 Indicates modulo 7 multiplication.

[0062] Described encoder is made up of optical encoding module, control circuit (comprising wavelength selection controller 20 and delay selection controller 21)...

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Abstract

The invention discloses a new structure of wavelength-time domain adjustable two- dimensional optical orthogonal coder / decoder applied to optical code division multiple access (OCDMA) communication network. The technical project: an OCDMA wavelength-time domain two-dimensional orthogonal coder / decoder, selects wave-time domain two-dimensional optical orthogonal code to make optical coding / decoding, and consists of optical coding / decoding module, control circuit and signalling agent; the optical coding / decoding module is controlled by the control circuit, which receives the instruction sent from the signalling agent to realize wavelength selection and delay selection; the signalling agent is connected with a signalling net; the optical coding / decoding module is composed of 1xN wave division demultiplexer, Nxw optical switch, w adjustable optical fiber delay line, wxN optical switch and Nx1 wave division multiplexer. The adjustable two-dimensional optical orthogonal coder / decoder of the invention can realize coding / decoding arbitrary two- dimensional wavelength-time domain optical orthogonal code and has a modularized structure, convenient to integrate.

Description

Technical field: [0001] The invention relates to the structure of an encoder and a decoder in an optical code division multiple access communication network system, and belongs to the technical fields of information network and optical fiber communication. Background technique: [0002] With the sharp increase in the types and volume of network services, especially the uncertainty and unpredictability of IP traffic, higher and higher requirements are placed on communication networks. In recent years, the use of DWDM technology to expand the backbone network and the research and development of automatic switching optical transmission network have made great progress in high speed, large capacity, long distance, etc., and are moving towards the direction of intelligence and efficiency. The metropolitan area network, especially the access network, has become the bottleneck of the communication network, which limits the development of the communication network. Therefore, it is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02F7/00H04J14/00
Inventor 殷洪玺徐安士吴德明
Owner PEKING UNIV
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