High power, high efficiency vertical cavity surface emitting laser for diode pumping

Princeton Optronics is a participant of the SHEDS program. In this program, we are developing high power, high efficiency VCSEL devices and arrays for pumping solid state lasers. VCSELs have a number of advantages over edge emitters which include: manufacturing simplicity, easy scalability in the form of 2D arrays for higher power, higher reliability because of lower power density in the aperture, and lower temperature sensitivity for wavelength shift (5X lower). Our approach to the design of high power VCSELs is a novel design and heat sinking of the active side of the device by mounting it face down on a diamond substrate. In the SHEDS program we have been able to improve the efficiency significantly, and to improve the array power to 80 W from a 5X5 mm array. We plan to develop 500 W output from a 10X10 mm array in the future. The temperature and wavelength uniformity achieved over the array in impressive. We have achieved a temperature uniformity of +/-5 deg C and a wavelength uniformity of +/-0.5 nm over the 80 W arrays. We have achieved an impressive yield of 80% for the 80 W arrays (with all devices working). With a partial n-mirror on the VCSEL and using a volume Bragg grating (VBG) in an external cavity configuration, we have achieved extremely narrow linewidth for the laser.