Photopolymer replication-a new technique for 0.25 μm phase shifted DFB-LD grating manufacture?

The photomask self interference (PSI) method utilises the interference field generated by the first and transmitted orders of a high precision grating. The authors describe a low cost replication process for PSI mask manufacture, and development to date, on an entirely new approach involving embossing directly into a thin film on the fragile semiconductor substrate. In both the techniques the aim is to produce high quality, uniform, profiles in a holographic recording material on the surface of the semiconductor substrate. These gratings are then used as a mask in the etching of the substrate that transfer the profiles into the waveguide layer. This novel approach aims to capitalise on the accuracy of the electron beam systems coupled with the high throughput and relatively low cost of a conventional contact mask regime