Mode-locked Raman fiber laser

Abstract

The invention discloses a mode-locked Raman fiber laser based on an adjustable filter. The mode-locked Raman fiber laser comprises two pumps, two wavelength division multiplexers, two sections of Raman fibers, two output couplers, a first fiber filter, a second fiber filter, an isolator, a plurality of sections of connecting fibers and four polarization controllers. The all-fiber laser is of an all-fiber structure, simple in structure, short in output laser pulse, high in power and stable in work. The laser has very strong application advantages in optical fiber communication, sensing and material processing.

Description

technical field [0001] The invention relates to the technical field of lasers, in particular to a mode-locked Raman fiber laser. Background technique [0002] Ultrafast laser has extremely high research significance and application value due to its narrow pulse width, high peak power, and large spectral width. It has been a hot spot in laser technology research since its invention. In recent years, ultrafast fiber lasers have attracted great interest due to their compact structure, good beam quality, high conversion efficiency, etc., as well as their great potential in terms of system heat dissipation and device cost. At the same time, due to the flexible and controllable nonlinearity and dispersion everywhere in the fiber, ultrafast fiber lasers have become an important platform for studying various ultrashort pulse shaping mechanisms and ultrafast phenomena. [0003] Most of the existing mode-locked fiber lasers are based on rare earth elements doped fiber as the gain med...

AI Technical Summary

Problems solved by technology

However, some special application fields, such as biomedicine and basic scientific research, have special requirements for the output wavelength of ultrafast lasers. At this time, conventional ultrafast fiber lasers using rare earth ions as gain media are difficult to meet the corresponding requirements due to the limitation of their gain bandwidth.

Generally speaking, their output wavelength is single and the output wavelength is limited, but the output power is high and the pulse time is short

[0004] The existing Raman fiber laser is based on Raman gain. As a special gain method, the Raman scattering effect in the fiber has the advantage of flexible wavelength. In theory, as long as there is a pump laser with a suitable wavelength, the fiber can be transparent. Lasers with any wavelength within the range, but it is difficult to achieve a mode-locked output for them

One of the reasons is that the recovery time of commonly used saturable absorbers such as graphene and carbon nanotubes is longer than the response time of Raman scattering, resulting in the inability of saturable absorption to be completely carried out.

On the other hand, because the longer gain fiber in the Raman fiber laser limits the repetition rate of the output pulse, it will produce a large nonlinear phase shift, so the mode-locked pulse is prone to splitting at high power

Generally speaking, the current Raman fiber lasers have low output power and long pulse duration.

Images