Fabrication of a Polymeric Ridge Waveguide Filter Using a Replication Process

Abstract

The traditional wavelength filter only have one face of grating, the gratings length must be long enough to obtain good filtering result, so the filter device can not be made to a small size. We describe a procedure for rapidly and conveniently prototyping Bragg grating on the three side of the polymer ridge waveguide using holographic interferometry and micro-molding processes. In this experiment, the master of the periodic structure was created on an i-line submicrometer positive photoresist film by a holographic interference using a He-Cd (325nm) laser. A subsequent mold using polydimethylsiloxane (PDMS) polymer was cast against this master and used as a stamp to transfer the grating pattern onto a UV cure epoxy. The technique shows accurate control for the transferring of a gratings period and depth. It can obtain the filtering result with very short grating length which means that it can be made with a small filtering device.