Active Q-switched fiber laser with narrow line width, narrow pulse width and high repetition frequency

Abstract

The invention discloses an active Q-switched fiber laser with a narrow line width, a narrow pulse width and a high repetition frequency. The output port of a pump source is connected to the pump portof a pump fiber combiner; the common end of the pump fiber combiner is connected with one end of a first doped fiber; the other end of the first doped fiber is directly used as an input fiber of a first port of a pump stripper 4; the second port of the pump stripper is connected with the first port of a fiber coupler; the third port of the fiber coupler is connected with a first port of a modulator; the fourth port of the fiber coupler is used as a laser output port; the second port of the modulator is connected with the first port of a circulator; the third port of the circulator is connectedwith one end of a second doped fiber; and the other end of the second doped fiber is connected with the signal end of the pump fiber combiner. The pulse width of the Q-switched pulse is narrowed, therepetition frequency of the Q-switched pulse can also be greatly improved, and thus, high-repetition frequency, narrow-line width and narrow-pulse width Q-switched pulse output can be realized.

Description

technical field [0001] The invention relates to the technical field of high-energy nanosecond laser pulses, in particular to an active Q-switched fiber laser with narrow line width, narrow pulse width and high repetition frequency. Background technique [0002] High-energy nanosecond laser pulses have extremely important applications in the fields of precision machining, laser radar, and nonlinear frequency conversion. Usually, such pulses are obtained by a MOPA system composed of a high-quality seed light source followed by a power amplifier, and the pulse seed sources mainly include directly modulated semiconductor lasers, Q-switched solid-state lasers, and fiber lasers. In contrast, Q-switched fiber lasers have the advantages of good beam quality, compact structure, high conversion efficiency, and little influence from subsequent power amplifiers, making them ideal seed sources for high-energy nanosecond laser pulses. At present, linear cavity Q-switched lasers based on ...

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Problems solved by technology

However, if you want to obtain a Q-switched pulse with a narrower linewidth, you need to use a sub-nanometer narrow-band filter, which will inevitably weaken the feedback strength of the resonator, and the gain self-saturation effect caused by a large amount of amplified spontaneous emission (ASE) will cause weak feedback. The signal is difficult to fully amplify in the gain fiber, making it difficult to obtain Q-switched pulses with narrow pulse width and high repetition frequency

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