A Low Repetition Frequency Short Pulse Fiber Amplifier Based on Special Phase Shift Fiber Bragg Grating Control Loop

Abstract

The invention discloses a low repetition frequency short pulse optical fiber amplifier based on a special phase-shifting fiber Bragg grating control loop. The low repetition frequency short pulse optical fiber amplifier comprises a seed pulse, a first pumping source, a second pumping source, a first coupler, a first wavelength division multiplexer, a first erbium-doped optical fiber, a first filter, a second filter, and a laser control loop, and the laser control loop is formed by a circulator, a first fiber grating, a second fiber grating, an adjustable attenuator, a second coupler, a third wavelength division multiplexer, a second erbium-doped optical fiber, and a second wavelength division multiplexer connected in sequence. The low repetition frequency short pulse optical fiber amplifier is mainly used in pulse power amplification occasions of the 1550 nm waveband in the field of optical fiber sensing, such as OTDR (optical time domain reflectometer), DTS (distributed fiber temperature sensing system), and BOTDA (Brillouin optical time domain analyzer) etc.

Description

technical field [0001] The invention relates to a fiber amplifier device, in particular to a low repetition frequency short pulse fiber amplifier based on a special phase-shift fiber Bragg grating control loop. Background technique [0002] Under the background that optical fiber distributed sensing is becoming more and more mature and the market is more and more widely used, how to improve the measurement accuracy and measurement length of the sensing system is the focus of researchers. As one of the core components of the optical pulse amplifier, its technical indicators are directly related to whether the system performance can be improved. EDFA is a broadband amplifier with an all-fiber structure used in the 1550nm band. Due to its good coupling efficiency, high reliability and compact structure, it has been widely used in optical pulse amplification. At present, in the application of continuous light and low-speed light pulse amplification, the noise control technology...

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Problems solved by technology

[0003] People have also proposed a variety of solutions to solve the problems of noise, nonlinearity, and dispersion of ultra-narrow pulses in high-power amplification. For example, some people use synchronous pumping, and only output pumping when the seed pulse enters the amplifier. Laser can minimize the ASE noise when there is no seed pulse, but there are also problems such as complex circuit and limited gain multiple caused by the small accumulation of inversion particles in the gain medium; The pulse is amplified in stages, and an isolator is inserted between the stages to reduce the influence of reverse ASE noise. Although the pulse can be amplified with greater power, it does not fundamentally solve the noise problem; The polarization controller reduces ASE noise through polarization extinction, but the polarization device will also introduce certain noise, and the stability of the polarization control is still uncertain.

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