Frequency-Agile Laser for Low Earth Orbit Satellite Velocity Compensation

Frequency-agile lasers with ultra-narrow linewidth are required for several coherent laser applications, including correction for Doppler frequency shifts between satellite platforms in low earth orbit. Coherent Technologies, Inc. proposes to develop a compact near-monolithic laser operating at 1.064 microns, tunable over its full range of 60GHz in 1ms. This tuning range allows correction for all possible relative velocities between platforms operating in low earth orbit. The tuning mechanism demonstrated during Phase 1 yielded 75-100mW single frequency output power while tuning continuously over 68GHz. The same mechanism will provide a settling time that is commensurate with the planned 1ms tuning period. Power scaling to >100mW over the full tuning range will be demonstrated. The tunable laser developed on Phase 2 will be packaged in the form of CTI’s standard METEOR® product, with dimensions of approximately 3.5” long X 2.3” wide X 1.5” tall. This program leverages off CTI’s previous work in frequency offset-locking of single frequency lasers for space-based platform compensation and laser frequency stabilization to ultra-stable reference cavities for long-range micro-Doppler measurements. 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.