Novel method for realizing spectral combination amplification based on frequency division multiplexing technology

Abstract

The invention discloses a novel method for realizing spectral combination amplification based on the frequency division multiplexing technology, which comprises the following steps of: (a), pre-amplifying and broadening laser pulse generated by an ultra-short pulse oscillator; (b), segmenting the frequency spectrum of a super-continuous broad-band spectrum into multiplex optical pulses with different central wavelengths; (c), amplifying each optical pulse, outputting a part of amplified seed light to a self-reference zero-frequency detection device by using a splitting slice, and taking a beat frequency signal output by the self-reference zero-frequency detection device as the driving frequency of an acousto-optic frequency shifter after filtering and amplifying; (d), coherently synthesizing amplification pulses output by various multi-stage optical fibre amplifiers through a wavelength division multiplexing beam combiner; and (e), carrying out dispersion compensation and pulse width compression of coherently synthesized pulses by using a compressor so as to obtain ultra-short pulse output with high peak power. According to the invention, the frequency division multiplexing technology and the coherent synthesizing technology are organically combined; therefore, the pulse synchronization problem and the spectrum coherent problem in the ultra-short pulse optical fibre laser coherent synthesizing process are solved.

Description

technical field [0001] The invention proposes a method for realizing spectral combination amplification based on frequency division multiplexing technology. Background technique [0002] High-power fiber laser pulses have important applications in basic scientific research, industrial processing, lidar, inertial confinement fusion, precision measurement, laser remote sensing and other fields. However, due to the limitations of thermo-optic effects, nonlinear effects, and the damage threshold of the gain medium, the average power of a single ultrashort pulse fiber laser is generally limited to hundreds of watts, and its peak power is generally on the order of gigawatts. [0003] For defects with limited single-channel amplification power, a multi-modular structure is adopted to control the phase of each fiber laser to achieve phase-locked output and realize coherent combination of pulses, which can increase the average power of the output laser by tens of times, and the peak ...

AI Technical Summary

Problems solved by technology

At present, there are three main methods for realizing pulse coherent combination. One is the polarization combination method, which uses a polarization beam splitter to divide the linearly polarized seed light source into several beams of light with different polarization directions, and then amplifies each polarized light component before performing Polarization beam combining, the disadvantage of this method is that the optical path difference of the unit beam needs to be adjusted precisely, and the phase of the polarized light component is difficult to be locked

The second is the passive coherent combination method, which automatically compensates the phase fluctuation of each laser through a certain energy coupling mechanism or nonlinear interaction to achieve phase locking. This method has low locking accuracy and poor device stability.

The third is the active coherent synthesis method, which can achieve high locking accuracy, but the structure of the required electronic feedback device is complex, and there is usually a large random time delay

According to the Fourier transform relationship, the narrowing of the gain spectral width will directly lead to the increase of the pulse width that can be achieved

[0006] 2. Intensity-phase noise

Non-linear chirp cannot be compensated by the chirp management device, which will split the pulse time domain and limit the peak power increase

[0008] 4. Dielectric gain bandwidth limitation

Based on the above factors, it is difficult for a single amplification device to further achieve high power amplification of pulsed light

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