Electric control tuning nonreciprocal phase shifter and polarization filter

Abstract

The invention relates to the technical field of laser, in particular to an electric control tuning nonreciprocal phase shifter, an electric control tuning polarization filter, an NALM mode-locked laser and a Sagnac ring. The fast / slow axis refractive index difference of a birefringent crystal is changed mainly through an external voltage. For a single beam of light, the effective optical path can be changed, and the equipment is applied to locking of repetition frequency and a polarization filter; for two beams of light, different phase delays can be introduced into the fast / slow axis by coupling the two beams of laser with the fast / slow axis of the modulation crystal and by applying the refractive index difference of the fast / slow axis of the voltage modulation crystal, and the equipment can be applied to an electric control tuning nonreciprocal phase shifter. The laser structure can be effectively simplified, the cost is reduced, and the application prospect is wide.

Description

technical field [0001] The invention relates to the field of laser technology, in particular to an electrically controlled tuned non-reciprocal phase shifter, a polarization filter, a NALM mode-locked laser and a Sagnac ring. Background technique [0002] In recent years, fiber-optic ultrashort pulse lasers based on waveguide structures, as a representative of the third-generation laser technology, have become a research hotspot due to their excellent stability, compact structure, and reasonable price. Fiber ultrashort pulse lasers are commonly used for mode-locking with solid and virtual saturable absorbers. The solid saturable absorber mode-locked laser has good self-starting performance and reproducibility, but it generally has a relaxation time of ps order, which will introduce relatively large noise to the pulse. Nonlinear polarization rotation (NPR) and nonlinear amplifying loop mirror (NALM) are two commonly used modes-locking mechanisms for virtual saturable absorbe...

AI Technical Summary

Problems solved by technology

However, the Lyot filters currently used are all fixed-length birefringent crystals and polarizers. The difference between the fast and slow axes of the refractive index is fixed, so it can only be used as an optical filter for a specific wavelength, and the output spectral width cannot be changed.

When other wavelength filtering is required, it can only be achieved by replacing the Lyot filter, which is time-consuming, labor-intensive and expensive

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