Dual-frequency-laser-based photoproduction tunable microwave source and frequency stabilization control method

Abstract

The invention discloses a dual-frequency-laser-based photoproduction tunable microwave source and a frequency stabilization control method for the same. A resonant cavity system of the photoproduction tunable microwave source comprises a semiconductor light amplifier chip, a collimating lens, a controlled half wave plate, a polarized beam splitter prism, a tunable filter and a reflector, which are sequentially arranged, wherein the reflector is formed by combining a tunable signal light vp reflection cavity mirror surface and a fixed frequency laser signal vs reflection cavity mirror surface into an L shape; the tunable signal light vp reflection cavity mirror surface and the fixed frequency laser signal vs reflection cavity mirror surface form resonant cavities with the output end face of the semiconductor light amplifier chip through corresponding beam split optical paths of the polarized beam splitter prism respectively; and a laser phase adjustment element capable of changing the optical cavity length of the resonant cavity formed by the tunable signal light vp reflection cavity mirror surface and the semiconductor light amplifier chip is arranged in the vp direction of the tunable signal light. By the microwave source and the method, a tunable microwave signal can be generated, and is large in tunable bandwidth and stable.

Description

technical field [0001] The present invention relates to an optically-generated tunable microwave source based on a dual-frequency laser and its frequency stabilization control method, in particular to an optically-generated microwave source for generating microwave signals at the beating frequency of a tunable dual-frequency laser and a method for stabilizing its frequency , the optically-generated tunable microwave source can be used in an optical-carrying radio frequency system, and the invention belongs to the field of communication. Background technique [0002] Microwave is regarded as a communication band in space communication and ground mobile communication. In addition, the wavelength of millimeter wave in microwave is very short compared with that of aircraft, ships and buildings. Strong reflection, which is widely used in military radar technology. Although microwave communication has been paid attention to, its own difficulties are becoming increasingly prominen...

AI Technical Summary

Problems solved by technology

Although microwave communication has been paid attention to, its own difficulties are becoming increasingly prominent: 1. Difficulties in the development of microwave to higher frequencies. Microwave signals exceeding 10 GHz are greatly attenuated in the atmosphere, and other microwave transmission media are transmitted over long distances. The loss of microwave signals is also very large, which limits the expansion of microwave signal transmission to high frequencies; 2. The research on the health effects of electromagnetic radiation brought by high-frequency radio frequency signals is still inconclusive, but the harm cannot be ruled out yet

3. The microwave wavelength is short, and the ability to avoid obstacles is poor, so microwave communication needs to build more base stations, resulting in double pressure

[0007] One is to use two independent lasers to beat frequency to generate microwave signals, one of which has a fixed frequency and the other has an adjustable frequency, and uses an optical phase-locked loop to lock the phases of the two lasers, such as the article "Johansson LA, Seeds A J.Millimeter-wave modulated optical signal generation with high spectral purity and wide-locking bandwidth using a fiber-integrated optical injection phase-lock loop.Photonics Technology Letters.2000,12:690-692”But this method is technically difficult not conducive to practical

[0008] The other is to use the same laser to generate lasers of two frequencies through related technical means, so that the microwave signal can be output directly, such as the US patent US7539221B1 "fiber-laser-based gigahertz sources through difference frequency generation by nonlinear optical materials" by changing the line shape The birefringence effect of the cavity fiber laser changes the frequency interval of the two lasers to realize the tuning of the microwave signal, but this method of applying stress to the laser fiber is random, which is not conducive to automatic control, and the entire laser is susceptible to environmental factors; US Patent US5497385 "optical microwave generator" uses two filters in the ring fiber laser, so that two lasers with unequal frequencies can simultaneously oscillate in the cavity to generate beat-frequency microwave signals, but this method based on fiber lasers is also susceptible to Due to the influence of environmental factors, the polarization states of the two frequency lasers cannot be well matched or difficult to stabilize, which ultimately affects the quality of the output microwave signal; the US patent "US7142570B2apparatus and method for generation optical carrier for microwave and millimeterwave photonics system" uses fundamental frequency light and optical fiber Stimulated Brillouin frequency-shifted light performs beat frequency to generate microwave signals, but this method is difficult to generate large-bandwidth tunable microwave signals; Chinese patent "CN100421318C Device for generating terahertz waves by dual-wavelength output photon mixing of semiconductor lasers" provides Up to the method of inserting an etalon and a spatial filter into the cavity of an external cavity semiconductor laser to generate a dual-wavelength output, the beat frequency signals of the two wavelength lasers enter the terahertz band, but this method is difficult to achieve the tuning of the beat frequency signals and the two The gain balance of wavelength laser in the cavity is not easy to guarantee

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