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Coherently-Combined High-Power Single-Mode Emitters (COCHISE)
Program Manager: Dr. Joseph Mangano
Coherently-Combined High-Power Single-Mode Emitters (COCHISE) aims to develop breakthrough technologies to dramatically improve diode bar lifetime, reliability, and beam quality. Additionally, these technologies will lead to high power, coherently-combined laser architectures that are up to three times more efficient than existing diode-pumped solid-state laser technology while improving beam quality and increasing far-field, on-axis intensity. The technologies developed under COCHISE will significantly enhance the performance of military laser systems for applications including high-power laser weapons, laser communications, laser countermeasures, and imaging laser radar.
In order to achieve its goals, COCHISE is developing four specific technologies:
1. Fault mode protection at the laser diode bar level: integrated optical and electrical fault mode detection technologies that sense the onset of filamentation and current hogging instabilities, therefore extending the lifetime of laser diode bars and also enabling operation of laser diode bars at higher junction temperatures.
2. New electrical and optical diode bar prescreening strategies: development of new prescreening technology based on the spectral signatures of individual emitters to detect packaging faults and other manufacturing defects that can lead to premature failure. This new technology will enable rapid, low cost, automated, non-destructive pre-screening of laser diode bars and allow pre-selection of laser diode bars having adequate lifetime for specific applications.
3. 100 watt stable diode bar with > 1 watt single-mode emitters: this effort will develop technologies that will intelligently drive individual laser emitting devices from its own current source, therefore eliminating current hog instabilities that preclude incorporation of new slab-coupled optical waveguide lasers (SCOWL) into >100 watt emitting array.
4. Methods for coherently combining high power, single-mode laser diode emitters: Preliminary experiments will be conducted to demonstrate current control of SCOWL diode phase to within 0.1 waves using an intelligent SCOWL diode driver that senses phase and controls current to maintain a preselected diode phase. A synthetic SCOWL diode bar will be developed with electrical access to each emitter. Each emitter will then be controlled by its own fault protected, intelligent current supply that will be integrated in CMOS. This will provide precise phase control of individual emitters enabling coherent beam combining to high power in Talbot cavities and in other cavities which support self-assembly of coherent supermodes.