Abstract

Efficient coupling of an injection laser diode to a thin film optical waveguide is difficult to achieve by using prism, grating, or tapered film couplers such as those generally used with gas lasers. The reason for this is that the injection laser has a relatively uncollimated emitted beam which diverges at a half angle of typically 10 to 20°. Prism, grating, and tapered film couplers are all very sensitive to the angle of incidence of the light beam, requiring collimation to better than 1° for efficient coupling. A more promising approach is to use the direct end-butt coupling scheme diagramed in Figure 1.

© 1976 Optical Society of America