Fiber femtosecond laser generating device and method based on triangular pulse passive forming

Abstract

The invention provides a fiber femtosecond laser generating device and method based on triangular pulse passive forming and belongs to the technical field of ultrafast laser. The device comprises a fiber passive mode-locked laser, a negative dispersion chirped fiber grating, a positive dispersion nonlinear passive fiber, a positive dispersion fiber amplifier, and a dispersion compensator. The fiber passive mode-locked laser produces an ultra-short laser pulse that passes through the negative dispersion chirped fiber grating to be converted into an ultra-short laser pulse with a negative chirp.The ultra-short laser pulse with the negative chirp is coupled into the positive dispersion nonlinear fiber to form a triangular narrow-band ultra-short laser pulse. The triangular narrow-band ultra-short laser pulse is coupled into the positive dispersion fiber amplifier to complete pulse self-similar amplification evolution and form a parabolic broadband linear chirped pulse. The broadband linear chirped pulse enters the dispersion compensator. The dispersion compensator compensates for the positive chirps accumulated by the broadband linear chirp pulse in the self-similar amplification process, to obtain the femtosecond laser with Fourier transform limit pulse quality.

Description

technical field [0001] The invention relates to an optical fiber femtosecond laser generating device and method based on triangular pulse passive shaping, and belongs to the technical field of ultrafast lasers. Background technique [0002] femtosecond(fs, 10 -15 s) Laser time resolution, coherent spectral width, peak power, time jitter and other performances are superior to traditional laser technology, which can bring breakthroughs in distance measurement, time-frequency transfer, precision machining, analog-to-digital conversion and other technologies. It has important application prospects in geophysical observation, communication, radar and navigation and other fields. Fiber femtosecond laser technology can overcome the inherent defects of Ti:Sapphire femtosecond laser system, such as expensive pump source, harsh environmental requirements, and thermal effects, and is an effective way for femtosecond lasers to achieve wide commercial applications. However, while the s...

AI Technical Summary

Problems solved by technology

In order to reduce the influence of gain shaping on the evolution process of self-similar amplification, there are usually two solutions: one is to use a longer gain fiber to improve the gain bandwidth of the fiber amplifier, but when the gain fiber is too long, the stimulated The Raman scattering effect will affect the chirp accumulation during the amplification process, thereby deteriorating the quality of the compressed femtosecond laser pulse, limiting the energy of the amplified output femtosecond laser pulse, and the longer the gain fiber, the greater the noise of spontaneous emission amplification; another The solution is to use a solid-state mode-locked laser oscillator with a smooth output pulse spectrum shape and a narrow spectral width as the seed pulse source, thereby indirectly reducing the limitation of the gain bandwidth on the evolution of pulse self-similar amplification, but this solution cannot achieve full fiber optics. Reduced compactness advantage of fiber optic systems

Images