Communications: Fiber-Coupled Eternal-Cavity Semiconductor High Power Laser

摘要

When this program was initiated in July, 1980, the state-of-the-art in semiconductor lasers had reached the point where as stated in the proposal 'these lasers must be given serious consideration for satellite-borne operation where reliability and power conversion efficiency are of prime concern. The key technical question which needs to be answered is whether a large number of these low-power semiconductor lasers can be coupled in parallel to produce a high-average power (approx. 1 kW) coherent laser beam.' During the 8-1/2 years of this contract this state-of-the-art has improved even more than forecasted in the proposal. Monolithic broad area or stripe-array lasers have been reported with output power of the order of 10 watts (compared to of the order of 10 milliwatts in 1980). In this program the coherent coupling of an array of individual semiconductor lasers by an external cavity has been demonstrated, a model of operation has been developed, and the model validated so one can extrapolate easily to the number of lasers needed for the 1 kW originally proposed. (RH)