Development of embedded Mach–Zehnder optical waveguide structures in polydimethylsiloxane thin films by proton beam writing

Abstract

A focused 750keV proton microbeam was used to fabricate an embedded Mach–Zehnder (MZ) optical waveguide in a polydimethylsiloxane (PDMS) film for interferometer application. The sample position was precisely controlled by a mechanical stage together with scanning microbeam to form an embedded MZ waveguide structure within an area of 0.3mm×40mm. The MZ waveguides with core size of 8μm was successfully embedded in PDMS film at a depth of 18μm by 750keV proton microbeam with fluences from 10 to 100nC/mm2. The MZ waveguides were coupled with an IR fiber-laser with a center wavelength of 1550nm and evaluated by using the transmitted intensity images from an IR vidicon camera. The results indicate that the embedded MZ waveguide structure in PDMS achieved single spot light propagation, which is necessary for building optical switching circuits based on polymer MZ waveguides.