Mode-locked all-fiber laser with all-normal-dispersion cavity

Abstract

The invention discloses a mode-locked all-fiber laser with an all-normal-dispersion cavity. A fiber laser structure is formed by rare earth-doped fibers, a polarization beam splitter, a band-pass long-period fiber grating filter, a semiconductor saturable absorber and the like, wherein the rare earth-doped fibers serve as laser gain mediums; the polarization beam splitter is used for splitting light; the band-pass long-period fiber grating filter is used for mode-locked laser center wavelength selection and mode-locked laser spectrum filtration optical pulse compression; and the semiconductor saturable absorber serves as a mode locking element. The fiber laser structure has high repetition rate, high power, simple structure and high efficiency. The mode-locked all-fiber laser works in an all-normal-dispersion area, and is an environmentally-stable all-fiber mode-locked ultrashort pulse laser with a novel structure. The mode-locked all-fiber laser can output polarized laser with picosecond and femtosecond light impulse length and the wavelength of more than 1 mu m, and after being amplified by a high-power fiber amplifier, the laser can be used for pumping-detection ultrafast optical physical experiments or environmental monitoring and microwave photonic and biophysical detection, dual-wavelength pumping-detection ultrafast optical physical experiments, sum frequency optical radiation generation, coherent anti-stokes raman scattering microprocessing and micromachining, and the like.

Description

technical field [0001] The invention relates to a fiber laser, in particular to a passively mode-locked all-fiber laser with high pulse repetition rate ultrashort laser pulse output, which is suitable for generating stable ultrashort laser pulse output for biomedicine such as multiphoton imaging microscopy Applications, etc. and the use of direct difference frequency method to generate ultrashort pulse mid-infrared laser radiation for pumping and detection of molecular systems and other scientific experiments, environmental monitoring and microwave photonics and biophysical detection, etc., belong to the field of optical information technology. Background technique [0002] Today's scientific experiments such as pumping and detection of molecular systems, environmental monitoring, microwave photonics and biophysical detection require mid-infrared light sources with high average power ultrashort pulses. In recent years, with the development of solid-state laser media such as ...

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Problems solved by technology

Its disadvantages are: 1. The spectral interval of the two different reflection peaks (with different polarization states) caused by the inherent large birefringence of the polarization maintaining fiber is relatively small and the adjustment range is very small; 2. Due to the use of narrow bandwidth Polarization-maintaining fiber grating is used as the reflective surface of the laser cavity, so it is difficult to achieve passive mode-locking to generate ultra-short laser pulses; 3. This cavity structure is suitable for narrow-linewidth tunable dual-wavelength fiber lasers

The above-mentioned technology adopts the concept of working in the negative dispersion region, and there are solid diffraction grating pairs or photonic bandgap fiber gratings in the cavity for dispersion compensation, etc., which also affects the full-fiber laser cavity and affects the long-term stability of the mode-locked fiber laser. Sex, or the cost of the laser is very expensive to affect its scope of use

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