Method for generating down link structure and frequency-tunable millimeter wave of millimeter wave optical fiber transmission system

Abstract

The invention relates to the down-link structure of a millimeter-wave fibre-optic transmission system and a method for generating millimeter waves with tunable frequencies. In the down-link structure of the millimeter-wave fibre-optic transmission system, double lasing light emitters are arranged in a key station, a first light wave passes through a double electrode Mach-Zehnder modulator, and a light carrier which carries digital baseband signals and comb spectral components which are spaced by the frequency of radio-frequency signals are generated at the output end of the modulator. A second light wave which passes through a circulator is taken as pump light and is injected into a polarization-preserving fiber in a reverse direction, the frequency of the second light wave is changed so as to amplify the comb spectral components of corresponding frequency points in the first light wave through stimulated Brillouin effect, and millimeter-wave signals with the corresponding frequencies can be generated at a photodetector on a base station. As the millimeter-wave signals are modulated by the digital baseband signals, the down transmission of information needed from the key station to the base station is realized. The RoF down-link has simple structure and realizes the purpose of simultaneously transmitting the digital baseband signals and the radio-frequency signals by utilizing one double electrode Mach-Zehnder photomodulator.

Description

technical field [0001] The present invention relates to a downlink structure of a millimeter-wave optical fiber transmission system and a method for millimeter-wave generation and millimeter-wave frequency tuning therein. A new downlink structure of the millimeter-wave optical fiber transmission system is proposed here. Dual light sources are introduced into the central station, and one channel of light waves passes through a dual-electrode Mach-Jeandel optical modulator to generate modulation signals and comb-shaped optical signals, and the other channel The light wave is reversely injected into the polarization-maintaining fiber as the pump light, and stimulated Brillouin scattering is generated to amplify the light wave at a certain frequency point in the comb spectrum. After the light wave is transmitted to the base station through the optical fiber, the photoelectric conversion generates the required millimeter wave signal, and the millimeter wave signal contains modulate...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to solve the problem that the downlink structure of the existing millimeter-wave optical fiber transmission system is complicated, the cost is high, and it is difficult to generate a frequency-tunable millimeter-wave signal, and to provide a downlink structure of the millimeter-wave optical fiber transmission system and a frequency-tunable mm wave generation method, tuning is achieved by changing the wavelength of the laser

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