Intermediate infrared cascaded pulse optical fiber laser

Abstract

The invention relates to an intermediate infrared cascaded pulse optical fiber laser, which comprises a semiconductor laser, a coupling lens group and a double clad ZBLAN optical fiber in sequential connection and is characterized in that a dichroic mirror is positioned in the coupling lens group, an optical fiber Bragg grating FBG<1>4 and an optical fiber Bragg grating FBG<2>5 are arranged between one end of the double clad ZBLAN optical fiber and the coupling lens group, the other end of the ZBLAN optical fiber is provided with a wide-spectrum reflector, and the surface of one side of the wide-spectrum reflector near the double clad ZBLAN optical fiber is provided with a saturable absorbing body using a graphene film as laser. The optical fiber Bragg grating FBG<1> and the wide-spectrum reflector form a first resonant cavity of the laser, and the optical fiber Bragg grating FBG<2>5 and the wide-spectrum reflector form a second resonant cavity of the laser. The intermediate infrared cascaded pulse optical fiber laser has the beneficial effects that the structure of the device is simple, the transportability and the integration degree are high, and the practical application is favorably realized.

Description

technical field [0001] The invention belongs to the field of laser technology, in particular to a pulse fiber laser. Background technique [0002] Fiber laser has significant advantages such as low laser threshold, good output beam quality, high conversion efficiency, high "surface area / volume" ratio, good flexibility and flexibility, and easy integration. In the recent research of pulsed fiber lasers, its wavelength is mainly The concentration is around 2.8um, and the methods adopted are mainly gain modulation, active Q-switching of acousto-optic modulator and passive Q-switching of saturable absorber. 1. The gain modulation method is to periodically modulate the number of particles in the energy level of the laser transition through the pulse pumping method to realize the pulse output of the laser, but this method requires pulse modulation of the pump light, which is easy to damage the pump laser and fiber end faces. 2. The active Q-switching of the acousto-optic modulat...

AI Technical Summary

Problems solved by technology

1. The gain modulation method is to periodically modulate the number of particles in the energy level of the laser transition through the pulse pumping method to realize the pulse output of the laser, but this method requires pulse modulation of the pump light, which is easy to damage the pump laser and fiber end faces

2. The active Q-switching of the acousto-optic modulator is to control the loss in the laser cavity by placing the acousto-optic modulator outside the fiber and in the resonant cavity to achieve the output of the Q-switched pulse. This method requires placing an acousto-optic modulator outside the fiber. Modulator, which makes the fiber laser lose its inherent advantages of flexibility, compactness, and small size. In addition, the material required for the mid-infrared band acousto-optic modulator is special, which increases its production cost and difficulty.

3. As for the passive Q-switching method of saturable absorbers, no saturable absorbers working in the band around 2.8um have been developed in the world.

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