Frequency-Agile Laser for Target Velocity Compensation

Frequency-agile lasers with ultra-narrow linewidth are required for several coherent laser applications, including correction for Doppler frequency shifts between fast-moving platforms, and column content Differential Absorption Lidar (DIAL) measurementsfrom Space with atmospheric depth biassing. Coherent Technologies Inc. proposes to develop a compact near-monolithic laser that provides 30GHz tuning capability, tunable over its full range in 1ms. The tuning mechanism will be intracavity phasemodulation to provide settling times that are commensurate with the 1ms tuning period. A master oscillator, power amplifier (MOPA) architecture is implemented to allow power scaling to the 1W level and above. This program will leverage off CTI's previousand existing work in frequency offset-locking of single frequency lasers for space-based platform compensation, and power scaling of single frequency lasers using large core fiber amplifiers to avoid nonlinear optical scattering. The tunable laser will bebased on Nd:YVO4, with amplification in an Yb:glass optical fiber. In the full configuration, a separate single frequency laser will be locked to a reference cell, and the tunable laser will be frequency offset-locked to the reference laser.