Double cladding large mode field area Yb-doped photon crystal optical fiber femtosecond laser

Abstract

The invention discloses a double-coating large-mode-area photon crystal flysecond laser directly obtaining micro joule-level single pulse energy, belonging to the field of laser technique and nonlinear optics, where the laser main body is based on double-coating large-mode-area photon crystal optical fiber of polarization-protection structure and adopts high-power LD laser to directly pump; the laser uses grating pair to compensate dispersion, starts mode locking with the help of semiconductor saturable absorber mirror (SESAM), and controls polarization by wave plate and polarization beam splitter and implements tunable output; laser resonant cavity keeps net positive dispersion inside and runs in self-similar mode locking mode and outside-cavity dispersion compensation is made on the output pulse and the pulse is 100-200fs wide. And the advantages: the laser has good stability, and the output pulse has high energy and high repeating frequency. And the invention can effectively avoid split of pulse running at high energy.

Description

technical field [0001] The invention relates to a double-clad large-mode-field-area ytterbium-doped photonic crystal fiber femtosecond laser, belonging to the fields of laser technology and nonlinear optics. Background technique [0002] Ultrashort pulse fiber laser has outstanding advantages such as stable operation, high integration, low price, and convenient maintenance. Ultrashort-pulse fiber lasers generally use passive mode-locking to obtain femtosecond-level laser pulses. The passive mode-locking methods of ultrashort-pulse fiber lasers include nonlinear polarization rotation mode-locking, nonlinear fiber loop mirror mode-locking, and semiconductor saturable absorbing mirror (SESAM) mode-locking. Nonlinear polarization rotation mode-locking needs to add many polarization control elements in the optical path, which is difficult to adjust, and this mode-locking method is easy to saturate at high pulse energy, so it is only suitable for low pulse energy ultrashort pulse...

AI Technical Summary

Problems solved by technology

First, such fiber lasers must be pumped using low-power single-mode diode lasers (LDs), limiting the level of energy injected

Second, the core of the traditional optical fiber is very small, which makes the high-energy ultrashort pulse have a strong nonlinear effect when it is transmitted in the fiber, which will lead to pulse splitting, thereby destroying the stability of the operation of the ultrashort pulse fiber laser

Traditional ultrashort-pulse fiber lasers operate in a soliton mode-locked mode, and the pulse shape is hyperbolic secant, and the nonlinear chirp introduced by it will cause pulse splitting

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