Nanosecond pulse optical fiber laser and control method thereof

Abstract

The invention provides a nanosecond pulse optical fiber laser with low background ASE noise, high pulse peak power, flat pulse and long service life, and further provides a control method thereof. The laser mainly comprises a control unit, a source laser, a noise suppression laser, an optical fiber coupler, a four-port optical fiber circulator, a four-stage optical fiber amplification part and a feedback part. By adopting the four-port optical fiber circulator and an FBG (fiber bragg grating) structure, the nanosecond pulse optical fiber laser realizes the amplification of four-stage optical pulse and can generate an optical pulse sequence with high peak power and high signal-to-noise ratio; by utilizing the noise suppression laser, the nanosecond pulse optical fiber laser realizes the control of inverted particle population in doped optical fibers, thereby suppressing the ASE background noise generated by an optical fiber amplifier and leading the wave form of output pulse laser to be flat. Meanwhile, as the gain-clamping technology is adopted to control gains of pulse light through the doped optical fibers, the source laser and the noise suppression laser work nearby the threshold current when not sending the optical pulse, thereby prolonging the service life.

Description

technical field [0001] The invention belongs to the technical field of lasers, and in particular relates to a nanosecond pulse fiber laser and a control method thereof. Background technique [0002] Long-distance fiber optic Raman sensors require that the pulse width of the sensing laser light source be on the order of nanoseconds (several nanoseconds to tens of nanoseconds), the peak pulse power can reach tens of watts or even hundreds of watts, and the pulse repetition frequency reach several From kilohertz to tens of kilohertz, it is necessary to use a nanosecond pulsed fiber laser with high peak power as its light source. Nanosecond pulsed fiber lasers currently on the market do not effectively control the number of inversion particles in the fiber amplification system, so that the generated pulsed laser has problems such as large background ASE (amplified spontaneous emission) noise, low peak pulse power, and uneven pulses. In addition, when the current pulsed fiber la...

AI Technical Summary

Problems solved by technology

Nanosecond pulsed fiber lasers currently on the market do not effectively control the number of inversion particles in the fiber amplification system, so that the generated pulsed laser has problems such as large background ASE (amplified spontaneous emission) noise, low peak pulse power, and uneven pulses. In addition, when the current pulsed fiber laser is not emitting light, the laser drive current is zero, which makes the laser service life short. The above reasons make the current pulsed fiber laser not suitable for long-distance Raman distributed fiber optic sensing systems

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