Super Gaussian pulse generation method and device on basis of gain reshaping

Abstract

A super Gaussian pulse generation method on the basis of gain reshaping includes the following steps: firstly, a wideband linear chirp laser pulse is generated, and the central wavelength of the wideband linear chirp laser pulse is adjusted to be longer than the intrinsic emission line peak wavelength of the doped gain ion of an optical fiber amplifier; secondly, the gain-narrowed lower triangular chirp laser pulse is obtained after the linear chirp laser pulse is gain amplified by a pre-amplifier selected with the gain coefficient spectral lines all presenting triangular shapes; finally, the super Gaussian pulse is formed by injecting the lower triangular chirp pulse into a main amplifier selected with the gain optical fiber length being 1 to 3 times of that of the pre-amplifier and the central wavelength of the gain spectrum lines being longer than the pre-amplifier. The device capable of realizing the method comprises an optical fiber femtosecond laser oscillator (9-1), a dispersion compensator (9-2), an optical fiber self-similarity pulse amplifier (9-3), a positive dispersion optical fiber pulse stretcher (9-4), a frequency spectrum filter (10), and a front optical fiber amplifier (11) with at least one stage and a main optical fiber amplifier (12).

Description

technical field [0001] The invention belongs to the technical field of ultrafast lasers, and relates to a method for generating high-power, high-signal-to-noise ratio broadband super-Gaussian pulses and a device for realizing the method. Background technique [0002] Fiber ultrashort pulse laser system can output femtosecond level (fs, 10 -15 s) Laser pulses, with excellent beam quality and stability, have been widely studied in the fields of scientific experiments and industrial production, and have become basic subjects such as physics and chemistry, new generation synchronous light sources, inertial confinement nuclear fusion and other large scientific projects, high It is a powerful tool for research in the fields of precision optical measurement, biomedical imaging, ultra-precision surgery, and micro-nano industrial processing. Compared with bulk solid-state laser systems represented by titanium sapphire, high-power fiber lasers also have outstanding advantages such a...

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Problems solved by technology

However, this active pulse shaping method by introducing additional passive discrete components not only can withstand low average power of incident light and limited spectral width, but also brings additional power loss and bandwidth loss to the amplification system, which is not conducive to Broadband pulse output with high power and high signal-to-noise ratio

In addition, most of the feedback control algorithms used in this type of shaping system are relatively complex, the system takes up a large space, and the optical path adjustment is difficult, which greatly increases the system cost and complexity, and thus also loses the optical fiber femtosecond laser amplification system. The main advantage, not conducive to practical application

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