Broadband adjustable and low-phase noise microwave signal generating device

Abstract

The invention discloses a broadband adjustable and low-phase noise microwave signal generating device, and belongs to the technical field of photoelectric oscillators. The device comprises a broadbandtunable laser and a first polarization controller connected with the broadband tunable laser, a polarized light beam splitter; a polarized light beam splitter which is divided into two light paths, and one light path is sequentially connected with the first single-mode optical fiber and the second polarization controller; the other light path is sequentially connected with a second single-mode optical fiber and a third polarization controller; and the two optical paths are connected with a broadband photoelectric detector, an electric power beam splitter, an electric spectrum analyzer, an electric low-noise power amplifier, an electric band-pass filter and a blocking device in sequence after passing through a polarized light beam combiner. According to the device, a universal Mach-Zehndermodulator and an erbium-doped fiber amplifier are not adopted, and a double-loop oscillation form is adopted, so that the integration level of the system is improved, and a broadband adjustable microwave signal with a relatively high side mode rejection ratio and relatively low phase noise can be provided.

Description

technical field [0001] The invention relates to the field of optoelectronics, in particular to a microwave signal generating device with adjustable broadband and low phase noise. Background technique [0002] Optoelectronic Oscillator (OEO), as one of the technical means of optically generated microwaves, has the advantages of simple structure, stable output signal, low phase noise, etc., and is widely used in radar systems, optical fiber communication systems, microwave photonic systems, optical wireless And high-precision measurement and other fields. [0003] Traditional OEO consists of laser light source, electro-optic modulator, erbium-doped fiber amplifier (Erbium-Doped Fiber Amplifier, EDFA), long optical fiber, photodetector, microwave power splitter, microwave amplifier, microwave bandpass filter and other optoelectronic devices. In order to realize the oscillation, EDFA or microwave amplifier can be used to compensate the optical loss or electrical loss in the pho...

AI Technical Summary

Problems solved by technology

Generally speaking, the traditional OEO usually adopts continuous wave laser external modulation technology, and the use of external modulators often leads to a large optical link loss, which requires a high-gain electrical amplifier (~60dB) to provide gain; at the same time, to Obtaining microwave signals with high spectral purity and low phase noise requires a long single-mode fiber for signal delay and energy storage to improve the Q value of the photoelectric loop

The phase noise of the microwave signal generated by OEO decreases with the increase of the fiber length. Therefore, increasing the length of the single-mode fiber is one of the important ways to improve the quality of the output microwave signal. However, with the increase of the fiber length, the volume of the system will also increase. , in addition, the mode interval of multi-mode oscillation in the photoelectric loop becomes smaller. In order to achieve single longitudinal mode oscillation, the Q value of the microwave bandpass filter needs to be greatly improved, which puts forward very high requirements for the current device production.

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