ABSTRACT
We have developed an ultra-low noise tunable Brillouin fiber laser exhibiting three orders of magnitude better frequency noise performance than the Neodymium-doped fiber laser pump and remarkable optical signal-to-noise ratio exceeding 80â dB suitable for immediate applications in coherent nonlinear conversion, quantum computing and underwater communications. In addition, we have implemented a custom optical phase-locked loop to ensure long-term stable operation and have investigated its impact on frequency noise. We demonstrate the power scalability of the single frequency (Hz-class) Brillouin laser, delivering over 500â mW with tunability across the 900â nm to 930â nm range in an all-fiber fully polarization-maintaining architecture.
ABSTRACT
We present the first frequency-quadrupled linearly-polarized Q-switched neodymium-doped fiber laser generating > 500â mW average power at 226â nm. For this purpose, an amplified Q-switched oscillator using novel large-mode-area (LMA) fibers and generating up to 24 W average power (15â kW peak power) at 905â nm was developed. Two nonlinear frequency conversion stages using a LBO crystal for SHG and a BBO crystal for FHG generate respectively up to 4.9 W average power in the deep blue at 452â nm and a maximum of 510â mW average power in the deep ultra-violet (DUV) at 226â nm. Performance limitations and further improvements are discussed.