Single-transverse-mode linear polarization state large-divergence-angle laser light source for interference measurement

Abstract

The invention discloses a single-transverse-mode linear polarization state large-divergence-angle laser light source for interference measurement. The single-transverse-mode linear polarization statelarge-divergence-angle laser light source comprises a laser, an optical fiber coupler, a standard single-mode optical fiber, a polarization controller and a large-numerical-aperture optical fiber; laser emitted by the laser is coupled into the standard single-mode optical fiber through the optical fiber coupler; the single-mode optical fiber passes through the polarization controller and then is connected with the large-numerical-aperture optical fiber through a mode field matching welding point; and finally the conducted laser is output through an optical fiber tapering output end. The laseris transitionally coupled to the large-numerical-aperture optical fiber by using the standard single-mode optical fiber; the laser transmission efficiency is improved through the mode field matching welding point; the single-mode optical fiber is coiled based on the stress birefringence principle, and the polarization state of the transmission laser of dissimilar welding optical fibers can be controlled; the output end of the large-numerical-aperture optical fiber is tapered, so that the light-emitting area of the output end can be reduced, and a laser divergence angle can be improved; finally, a large-divergence-angle laser light source with a single transverse mode and a linear polarization state is obtained, so that the background uniformity of interference fringes in the interference measurement is improved.

Description

technical field [0001] The invention belongs to the field of laser light sources, in particular to a single transverse mode linear polarization state large divergence angle laser light source for interferometric measurement. Background technique [0002] Laser has excellent time coherence and is widely used in the field of interferometry. For example, a laser interferometer uses a laser as a light source to obtain interference fringes with high contrast and improve measurement accuracy. Currently, HeNe lasers are widely used as light sources in commercial interferometers. Moreover, the fiber-coupled laser technology can separate the light source from the host of the interferometer, reducing the volume and heat source of the interferometer. [0003] A standard single-mode fiber is usually used as the coupling fiber of the He-Ne laser, which can filter out high-frequency noise and improve the signal-to-noise ratio of the output wavefront. However, the use of standard single...

AI Technical Summary

Problems solved by technology

However, in this technical solution, due to the large numerical aperture relative to the standard single-mode fiber, the mode field diameter is small, and direct fusion will produce large fusion loss, and the fiber-coupled single-mode light source does not achieve a good polarization extinction ratio.

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