Low noise fiber femtosecond laser amplifier based on pre-chirp management

Abstract

Provided a pre-chirped management based low-noise fiber femtosecond laser amplifier. The amplifier comprises an ytterbium-doped fiber dispersion management mode-locked laser (1), a spectral interference filter (2), a grating negative dispersive delay line (3), an ytterbium-doped fiber amplifier (4), and a grating pulse compressor (5). The ytterbium-doped fiber dispersion management mode-locked laser (1) generates a breathing soliton pulse sequence; the spectral interference filter (2) adjusts a center wavelength of the breathing soliton pulse sequence and enables it in the gain spectrum center of the ytterbium-doped fiber amplifier (4); the grating negative dispersive delay line (3) introduces a negative chirp into the adjusted breathing soliton pulse sequence, thereby obtaining a seed pulse; the ytterbium-doped fiber amplifier carries out self-similar amplification on the seed pulse, thereby obtaining a parabolic pulse; and the grating pulse compressor (5) compresses the parabolic pulse and generates a femtosecond laser pulse. According to the high-frequency noise of a linear amplifier effectively inhibited by the pre-chirped management based low-noise fiber femtosecond laser amplifier disclosed by the present invention, a Fourier transform-limited femtosecond laser pulse with a narrow pulse width is obtained.

Description

technical field [0001] The invention relates to the field of ultrafast laser technology, in particular to a femtosecond laser amplifier. Background technique [0002] Based on the high time resolution, broadband frequency comb and low time jitter characteristics of femtosecond lasers, it is possible to obtain distance measurement and time synchronization accuracy, scale and speed that are difficult to achieve by traditional methods. It is used in deep space exploration, communication navigation, space remote sensing and other fields It has broad application prospects. Fiber femtosecond laser is most likely to take the lead due to its almost fully enclosed optical path, integrated optical fiber device and direct pumping method of semiconductor laser diode (LD), which has outstanding advantages such as good environmental stability, good beam quality and compact structure. A practical light source for femtosecond laser space applications. In order to improve the output index ...

AI Technical Summary

Problems solved by technology

However, the limited gain bandwidth of fiber amplifiers will seriously hinder the process of pulse self-similar evolution, deteriorating pulse shape and chirp

The existing femtosecond laser self-similar amplifiers mostly use long optical fibers (≥6m) to increase the gain bandwidth, but this increases stimulated Raman scattering and ASE noise, which limits the output power and signal-to-noise ratio

In addition, most of the existing low-noise fiber amplifiers use active feedback control loops to stabilize the LD current pumped by the amplifier, so as to effectively reduce the additional noise in the amplification process. The effective suppression of high-frequency noise limits the dynamic synchronization application of femtosecond lasers

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