Shanghai Institute Of Optics And Machinery Makes Progress in Precision Synchronization Of Ultrashort Pulse Lasers Using Anti-resonant Hollow-core Fibers

Recently, the State Key Laboratory of Strong Field Laser Physics, Shanghai Institute of Optics and Precision Machinery, Chinese Academy of Sciences, Russell Center for Advanced Lightwave Science, Hangzhou Institute of Optics and Precision Machinery, Efibe (Ningbo) Optoelectronics Technology Co., Ltd. and Wuhan University of Technology have made progress in achieving precision synchronization of ultrashort pulse lasers using anti-resonant hollow core fiber. The research team reported for the first time the active synchronization technology of ultrashort pulse laser based on anti-resonant hollow core fiber, which achieves low noise and high efficiency transmission and precision time control of broadband ultrashort pulse laser with 2.23 fs (RMS) synchronization accuracy. The research results were presented as "Highly stable, flexible delivery of microjoule-level ultrafast pulses in vacuumized anti resonant hollow-core fibers for active synchronization" was published in Optics Letters.
The high-precision synchronization control technology based on ultrashort pulse lasers has been widely used in various gas pedals and intense laser devices, which has greatly improved the time control accuracy of large scientific devices. The key to high-precision time synchronization is to ensure the long-distance stable transmission of ultrashort pulse lasers. The traditional quartz fiber is difficult to achieve high performance transmission of ultra-short pulse lasers with single pulse energy above micro-joule. This is due to the high peak power of ultra-short pulse lasers in the microjoule range, which can rapidly accumulate excessive nonlinearities in the fiber with a fused silica core, resulting in distortion of the pulse in both the time and frequency domains.
To address this problem, the research team used an anti-resonant hollow-core fiber to achieve stable and efficient transmission of ultrashort laser pulses with a single pulse energy of the order of microjoules and a pulse width of less than 200 fs, and successfully used it for high-precision laser pulse synchronization studies. When the ultrashort laser pulses are transmitted in the evacuated anti-resonant hollow-core fiber, their spectra and pulse widths remain largely unchanged due to the effective suppression of gas nonlinear effects, and the laser pulses at the output of the fiber are comparable to those at the input in terms of average power and spectral stability. Thanks to the waveguide characteristics, the output laser pointing stability is improved from 6 μrad to 1 μrad, and the jitter of the laser pulse can be controlled to 2.23 fs (RMS) within 90 min after transmission through a 10 m hollow-core fiber. This study verifies the feasibility of ultrafast optical-optical synchronization based on antiresonant hollow-core fiber, and points out the potential of antiresonant hollow-core fiber for time synchronization control of large laser and gas pedal devices.
The related work was supported by the National Natural Science Foundation of China, the National Postdoctoral Innovation Talent Support Program, the Chinese Postdoctoral Science Foundation, the Young Team Program in Basic Research of the Chinese Academy of Sciences, the Basic Research Program of Shanghai Science and Technology Innovation Action Plan, and the Zhangjiang Laboratory Construction and Operation Program.