An all-fiber optical frequency shifter based on acousto-optic effect and its frequency shifting method

Abstract

The invention discloses an all-optical-fiber optical frequency shifter based on acousto-optic interaction and a frequency shifting method thereof. Two sections of diameter-reduced acousto-optic interaction zones are made on a wrapping layer of a single mode fiber, a spacing zone is arranged between the two interaction zones, and a cone vertex of an ultrasonic pyramid is bonded to the spacing zone;a radio-frequency signal generator sends out an electrical signal, an ultrasonic transducer converts the electrical signal into an acoustical signal, and the acoustical signal is amplified by the ultrasonic pyramid and then is transmitted to the single mode fiber; when incident light meets phase matching conditions, frequency shifting light is produced with mode switching of the single mode fiber, and the frequency shifting frequency is two times of the exerted acoustical wave frequency. The requirements of an ultrasonic pyramid and single mode fiber bonding process are reduced in actual operation by adopting the all-optical-fiber optical frequency shifter. The cost is successively reduced by using the single ultrasonic pyramid. What's more important is that the single ultrasonic pyramidis adopted, insertion loss is reduced, package is facilitated, and application is promoted. In addition, the all-optical-fiber optical frequency shifter has the advantages of being adjustable in frequency shifting amount and signal-to-noise ratio and being directly applied to optical fiber pathways.

Description

technical field [0001] The invention belongs to the field of optical information processing, and in particular relates to an all-fiber optical frequency shifter based on acousto-optic effect and a frequency shifting method thereof. Background technique [0002] Optical heterodyne detection is an important method in optical coherent detection. It coherently superimposes different frequencies of laser light to form a beat frequency, and realizes the detection of the target by demodulating the phase of the beat frequency signal. The characteristic is to convert the extremely high-frequency light frequency into the intermediate frequency frequency that the detector can respond to. The key technologies in the application process include detection of weak signals, beat frequency demodulation technology, and laser light source frequency stabilization technology. Compared with homodyne detection, optical heterodyne detection has the advantages of higher sensitivity, accuracy and s...

AI Technical Summary

Problems solved by technology

This system can realize frequency shifting from 1Hz to 100Hz, and has the advantages of small size, low driving frequency and power, but the insertion loss of this set of devices is large, and it cannot be used in applications, and the driving process requires two cascaded pyramids , requires double the drive, increasing the cost of use

[0004] All in all, although the optical frequency shifter has important applications, the current all-fiber frequency shifter is still not practical

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