Highly Efficient, Power-Scalable Long-Wavelength Diode Laser Pumps for Eye-Safe Solid-State Laser Development

For Phase II of this program, Princeton Lightwave Inc. proposes to develop high power 1470 nm InGaAsP/InP diode laser arrays and stacks with dramatic improvements relative to the current state-of-the-art performance for threshold, differential efficiency, and wall-plug efficiency. These lasers will be based on a broadened waveguide structure employing an AlInAs blocking layer. Using these emitters, we will provide 1-cm arrays with power conversion efficiency of 45 - 50% and a maximum power of 130 W, as well as 10-array stacks with power exceeding 1 kW. In addition, we will apply spectral narrowing to these stacks using volume Bragg grating (VBG) technology to provide at least 500 W in a 1.5 nm spectral window. To achieve these goals, we will use our existing InP-based diode laser platform with which we have already demonstrated 54 W CW operation at 1530 nm from 1-cm arrays during Phase I of this program. These arrays had 30% conversion efficiency at maximum power, and we demonstrated 230 W output power for VBG-stabilized stacks. Arrays developed for Phase II of this program will provide unprecedented performance for eye-safe diode-pumped solid state lasers as well as for direct diode use. Moreover, the achievement of these Phase II goals will constitute a leap in 14xx nm pump laser performance that is proportionally comparable to the performance improvement for short-wavelength (GaAs) pump lasers achieved in DARPA’s SHEDS program.