The Optimization of Compact High Energy Fiber CPA System for Bio-Imaging Applications

High energy ultrashort pulse fiber chirped pulse amplification (FCPA) systems are increasingly attractive for biological and biomedical imaging especially for implementing of wide-field microscopy techniques as high energy wide field illumination enables faster data acquisition. These applications require carefully tailored output parameters and long operational lifetime of the laser system. Nonlinear effects, however, limit the amplification of ultrashort optical pulses in fiber amplifiers due to long interaction length and small mode area of the gain fibers. Fiber CPA technique allows achieving significantly higher pulse energies (tens of μJ from single mode fiber amplifiers) by reducing nonlinear effects in a gain fiber by stretching initial pulse and de-chirping the pulse after the amplification. This task can be performed in ultrafast fiber laser configuration using chirped fiber Bragg grating (CFBG) as pulse stretcher and chirped volume Bragg grating (CVBG) as pulse compressor as it was proposed in [1,2]. However, in these systems, compressed pulses were not transform-limited and had residual non-compressed pedestal due to the lack of management of higher order dispersion in the system. In our previous work, we presented compact FCPA system consisting of CVBG compressor and CFBG stretcher that was manufactured with matched chromatic dispersion profile to achieve high fidelity compression of femtosecond pulses [3].