Abstract

We describe the fabrication of thin plastic grating couplers which can be conveniently attached to a film waveguide and later removed after use. These gratings provide the most convenient and economic means of coupling light into a thin film waveguide. Prism couplers are bulky, often expensive, need frequent repolishing and require considerable expertise for good coupling. Forming a holographic grating coupler directly on the guide requires a large investment in both equipment and time and a separate grating must be made each time the coupling position has to be changed. Thus, both commonly used coupling methods are costly and tend to degrade the waveguide after repeated coupling attempts. In the present scheme, 100 gratings can be made simultaneously in one step and stored for future use. Only one master grating is needed for replication purpose. These couplers can be applied at any position on the guide and removed without damage to the guide.

© 1976 Optical Society of America