ROF (radio over fiber) system based on dual-modulator parallel structure

A dual modulator and modulator technology, applied in transmission systems, electromagnetic wave transmission systems, instruments, etc., can solve problems such as increasing system costs, and achieve the effects of improving utilization, easy engineering application, and simple structure

Inactive Publication Date: 2011-10-26
BEIJING JIAOTONG UNIV
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  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

In the ROF uplink, in order to reduce the frequency of the received signal and demodulate the baseband signal, a high-frequency local oscillator is often required

Method used

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  • ROF (radio over fiber) system based on dual-modulator parallel structure
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  • ROF (radio over fiber) system based on dual-modulator parallel structure

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Embodiment Construction

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] A ROF system based on a dual modulator parallel structure, as shown in the figure, the ROF system includes: first and second lasers 10, 11, 3dB coupler 20, sinusoidal signal generator 21, first and second dipoles Mach-Zehnder modulators 30, 31, first to fifth photodetectors 40, 41, 42, 43, 44, erbium-doped fiber amplifier 22, first and second fiber Bragg gratings 60, 61, first and second Two circulators 50, 51, first and second single-mode optical fibers 70, 71, transmitting antenna 23, receiving antenna 28, first and second mixers 80, 81, optical intensity modulator 24, demodulator 25, First and second phase shifters 26, 27, first and second low-pass filters 90, 91.

[0023] The connection and working principle between the above parts are as follows:

[0024] The output end of the first laser 10 is connected to the input end of the 3dB coupler 20, the first o...

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Abstract

The invention discloses an ROF (radio over fiber) system based on a dual-modulator parallel structure, and relates to the fields of microwave photons, fiber-optical communications and the like. In order to overcome the technical difficulties in generating downlink high-frequency doubling MMWs (millimeter waves) and underclocking the uplink high-frequency signals in an existing ROF system, a structure that a first dual-pole Mach- Zehnder modulator is connected with a second dual-pole Mach-Zehnder modulator (30 and 31) in parallel is adopted to generate multi-frequency harmonic components. A first OFBG (optical fiber Bragg gratings) (60) and a second OFBG (61) as well as a first circulator (50) and a second circulator (51) are utilized to select frequencies; and a first photoelectric detector (40), a second photoelectric detector (41), a third photoelectric detector (42), a fourth photoelectric detector (43) and a fifth photoelectric detector (44) are utilized to generate downlink quadruple-frequency MMWs and signals of after uplink signal underclocking. The frequency of the output signals of a sinusoidal signal generator (21) are within the range from 1GHz to 30GHz, MMW signals within the range from 4GHz to 120GHz can be generated, and the signals for the underclocking of the uplink signals can be provided. A first mixer (80) and a second mixer (81) are used for mixing the uplink high-frequency signals with the underclocked signals so as to reduce frequencies of uplink signals.

Description

technical field [0001] The invention relates to optical fiber wireless communication, microwave photon technology and frequency up-conversion technology, and is applicable to the fields of optical fiber-wireless communication system technology, microwave photon, optical fiber communication and radar. Background technique [0002] ROF (Radio Over Fiber) is a technology that combines optical fiber communication and wireless communication. Its characteristics of large capacity, low cost and low power consumption make it one of the most promising technologies for ultra-broadband wireless access. In the ROF system, optical fiber communication is used to replace a section of microwave transmission from the central station (CS, Central Station) to the base station (BS, Base Station) in traditional wireless communication. The central station is connected to multiple base stations with simple functions through optical fiber. Complex functions such as modulation and demodulation, enco...

Claims

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Application Information

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IPC IPC(8): H04B10/12G02F1/35H04B10/2575
Inventor 高嵩裴丽宁提纲祁春慧赵瑞峰李卓轩刘超
Owner BEIJING JIAOTONG UNIV
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