Optical device structure using GaN substrates for laser applications
View Patent ↗An optical device includes a gallium nitride substrate member having an m-plane nonpolar crystalline surface region characterized by an orientation of about −1 degree towards (000-1) and less than about +/−0.3 degrees towards (11-20). The device also has a laser stripe region formed overlying a portion of the m-plane nonpolar crystalline orientation surface region. In a preferred embodiment, the laser stripe region is characterized by a cavity orientation that is substantially parallel to the c-direction, the laser stripe region having a first end and a second end. The device includes a first cleaved c-face facet, which is coated, provided on the first end of the laser stripe region. The device also has a second cleaved c-face facet, which is exposed, provided on the second end of the laser stripe region.
1. A method for forming an optical device comprising:
providing a gallium and nitrogen containing member having an m-plane nonpolar crystalline surface region characterized by a laser stripe region overlying a portion of the m-plane nonpolar crystalline surface region, the laser stripe region being characterized by a cavity orientation substantially parallel to a c-direction, the laser stripe region having a first end and a second end;
forming a pair of facets including a first c-face facet provided on the first end of the laser stripe region and a second c-face facet provided on the second end of the laser stripe region; and
subjecting the first c-face facet to a deposition process.
2. The method of claim 1 wherein the deposition process includes coating the first c-face facet with a reflective material; and wherein forming the pair of facets comprises separately forming the first c-face facet and the second c-face facet.
3. The method of claim 1 wherein the pair of facets is formed before a singulating process; and wherein the m-plane nonpolar crystalline surface region is characterized by an off-cut orientation of about −1 degree towards (0001) and less than about 0.3 degrees towards (11-20).
4. The method of claim 1 wherein the optical device is configured as single lateral mode optical device or a multi-mode optical device.
5. The method of claim 1 wherein the optical device is characterized by a wall plug efficiency of 14% and greater.
6. The method of claim 1 wherein the optical device is characterized by a wall plug efficiency of 18% or 20% or 23% and greater.
7. The method of claim 1 further comprising maintaining the second c-face facet as substantially exposed gallium and nitrogen containing material.
8. The method of claim 1 wherein the first c-face facet and the second c-face facet are cleaved facets.