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 is a combination of electro-optic intracavity phase modulation and electro-optic tuning of a mode-selecting etalon, providing settling times that are commensurate with the 1ms tuning period. Power scaling from a previously demonstrated single frequency power value of 50mW to >100mW will be evaluated. The tunable laser developed on Phase II will be packaged in the form of CTI's standard METEORr 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. The Phase I program will include a preliminary tuning demonstration of the frequency-agile laser and characterization of etalon requirements for power-scaling single frequency operation.