Single-Frequency Semiconductor Lasers Operating at 1.5 and 2.0 microns

While conventional injection seeding sources (such as DFB diode lasers and rare-earth doped solid-state microchip lasers) are available at 1.5 microns, these sources typically lack the ultra-narrow (<50 kHz), ultra-stable output spectrum required for use in applications such as Doppler shift measurements of the tropospheric winds. Furthermore, similar sources which operate at 2.0 microns (a preferred wavelength for space-based atmospheric measurements) are simply unavailable. Based on promising results obtained under NASA Phase 1 SBIR funding, nLight proposes the parallel development of 1.5 and 2.0 micron injection seeding sources based on our well-established, wavelength-scalable, industry-leading InP semiconductor laser design. Optical feedback provided by external volumetric or fiber Bragg gratings serves to narrow the semiconductor linewidth to the appropriate level. If necessary, further linewidth reduction can be achieved by means of electronic feedback circuitry. The line-stabilized diode lasers will be integrated with nLight's exiting space-qualified (space flown), hermetically-sealed, compact single-mode diode package, efficiently coupled to single mode fibers, and delivered to NASA.