All fiber Q-switch

Abstract

The invention relates to an all fiber Q-switch, which comprises a fiber, a V-shaped groove, a long-period grating pressed template, piezoelectric ceramics, a semiconductor chilling plate, a thermistor and a metal shell, wherein the fiber passes through the metal shell, and one section of the fiber is a bare fiber; the long-period grating pressed template, the bare fiber and the V-shaped groove are arranged from top to bottom in the metal shell to form a sandwich-like structure; optical cement is coated on the outer surface of the bare fiber; the piezoelectric ceramics is arranged between the inner top of the metal shell and the long-period grating pressed template; the semiconductor chilling plate closely attaches to the outer bottom of the metal shell; and the lateral surface of the V-shaped groove is closely provided with the thermistor for inducing the temperature of the V-shaped groove. The all fiber Q-switch has the characteristic of zero insertion loss. When the all fiber Q-switch is applied to a Q-switched fiber laser, the all fiber Q-switch can improve the output power and efficiency of the laser under the same conditions.

Description

technical field [0001] The invention relates to a Q switch, in particular to an all-fiber Q switch based on a long-period fiber grating. Background technique [0002] In some applications such as industrial laser marking and laser cutting, laser pulses with high peak power are required, which can usually be achieved using Q modulation technology. The basic principle of Q modulation technology is to make the loss (or Q value) in the laser resonator cavity change according to a preset program through a certain method. At the beginning of the pump excitation, the resonator has high loss (low Q value), and the laser cannot generate laser oscillation due to the high threshold, so the number of particles in the metastable state can accumulate to a higher level. Then at the set moment, the loss of the resonant cavity is suddenly reduced to a very low value (high Q value), and the laser threshold is immediately lowered. At this time, the number of inversion particles greatly exceed...

AI Technical Summary

Problems solved by technology

[0007] However, there are obvious deficiencies in this technology, which limit its application range

First of all, it is necessary to write long-period fiber gratings on the optical fiber in advance, which requires expensive special writing equipment, and requires the optical fiber to be photosensitive, that is, to be able to write gratings

Secondly, because the phase shift of the phase-shifted long-period fiber grating is different, its transmission spectrum will be very different, so it is necessary to precisely tune the local phase of the long-period fiber grating, otherwise the performance of the device will not be guaranteed

Finally, the central wavelength of the long-period fiber grating is very sensitive to temperature. If no temperature control technology is added, the ambient temperature changes, and the central wavelength of the grating will drift, which will cause the Q-switched fiber laser to fail to work normally.

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