A fiber laser based on spectrum adjustment and its realization method

Abstract

The invention discloses an optical fiber laser device based on spectrum adjustment and an implementation method of the optical fiber laser device. The optical fiber laser device comprises a seed source, an erbium-doped optical fiber amplifier, a pulse narrowing system and a frequency doubling filtering system, wherein a polarization controller is arranged at the tail end of a gain optical fiber, and the pulse narrowing system adjusts the length of a pre-chirp optical fiber through a prism pair so that the negative dispersion of the pre-chirp optical fiber and negative dispersion of the prism pair offset the positive dispersion of the gain optical fiber. The magnitude of the negative chirp of a femtosecond pulse is adjusted by adjusting the length of the pre-chirp optical fiber before amplification, and therefore the magnitude of the negative chirp of the femtosecond pulse is controlled before amplification, the nonlinear effect is controlled in the amplification process, and the frequency doubling efficiency is optimized; the polarization controller is added to the gain optical fiber, the polarization degree of an output pulse of an amplifier is adjusted, losses caused when signal light is reflected by the prism pair of the pulse narrowing system are reduced, and therefore higher fundamental frequency optical power is obtained.

Description

technical field [0001] The present invention relates to a fiber laser, in particular to a fiber laser based on spectrum adjustment and its realization method. Background technique [0002] Near-infrared ultrashort pulses have great application value in terahertz technology, two-photon imaging technology, coherent anti-Stokes scattering microscopy and other fields. For the above application fields, the solid-state laser Ti:Sapphire mode-locked laser is the mainstream device for generating femtosecond pulses. Although Ti:Sapphire lasers are widely used in the field of scientific research, they also have a series of insurmountable shortcomings such as high price, poor stability, frequent maintenance, and strict requirements on the stability of the working environment. This also hinders the further development of Ti:Sapphire solid-state lasers. [0003] In recent years, with the emergence of femtosecond-level fiber lasers, it has also become a strong competitor of femtosecond ...

AI Technical Summary

Problems solved by technology

However, due to the nonlinear effect and dispersion of light propagating in the light, the ultrashort pulse will be deformed, so it is very difficult to increase the average power of the erbium-doped fiber laser in the 1550nm band, and it is more difficult to obtain a higher near-infrared after frequency doubling. The average power of the femtosecond pulsed laser in the band

[0004] At present, someone has used an erbium-doped fiber femtosecond laser with a double-arm repetition rate of 98MHz to obtain a femtosecond fiber laser with a band of 770nm and an average power of 120 mW. This type of fiber laser usually uses a chirped periodic pole Lithium niobate frequency doubling crystal, commercial frequency doubling crystals usually cannot obtain high frequency doubling efficiency; the output power of similar near-infrared femtosecond laser can also be obtained through multimode erbium ytterbium co-doped fiber amplifier

However, in the system of multimode erbium-ytterbium co-doped fiber amplifier, lens coupling is usually required, which has strict requirements on the stability of the environment and is easy to lose coupling

In addition, the use of a gain fiber with a large mode field area easily loses the original flexibility of the fiber, and instead makes it larger than similar estimated laser amplifiers

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