Novel devices for ultrashort pulse fiber laser technology

Two novel devices, monolithic pulse shaper and photo-thermo-refractive (PTR) glass based chirped volume Bragg grating (CVBG) were demonstrated in this dissertation. They are compact, robust, easily to integrate with fiber laser systems. Furthermore, a high-energy fiber-based chirped pulse amplification (FCPA) system was also demonstrated and the first fiber laser driven hard X-ray generation was achieved.; The monolithic pulse shaper was demonstrated on a platform which combines a chirped fiber Bragg grating with a micro-machined actuator array together. The CFBG served as a dispersive device which spectrally separated different frequency components of ultrashort optical pulses longitudinally along the grating and high-force micro-actuators thus can locally access and modify the Bragg condition and induce extra phase-shift.; The PTR glass based CVBG was demonstrated as an alternative approach to compact high-energy ultrashort pulse compressor. With the unique property of the PTR glass, a homogeneous transverse aperture can achieve several millimeters. This provides the aperture scalability and extended the applicability of chirped Bragg grating to bulk material. The proof-of-the-principle experiment was demonstrated at 1.55 mum and high-energy demonstration was accomplished at 1 mum with 1.3-ps and 200-muJ compressed pulses.; The high-energy setup was dedicated to explore pulse energy and pulse duration potential of an FCPA system. With a proper excitation of 65-mum core fiber, a mode quality of M2 < 1.05 was achieved. The system was able to achieve 1.5-mJ for ∼1-ns stretched pulses. The highest achieved recompressed pulse energy was 500-muJ (800-muJ before compressor) with 500-fs pulse duration.; The first femtosecond fiber laser based hard X-ray source was also successfully demonstrated using the high-energy FCPA system as a laser driver. 300-fs, 45-muJ pulses were tightly focused on nickel target and distinctive K alpha-line emission was observed. The conversion efficiency reached eta Kalpha = 4.5 x 10-8 which is comparable to traditional solid-state laser driven hard X-ray yield in the sub-millijoule regime.