Monolithic single-mode SU-8 waveguides for integrated optics
Publikation/Tidskrift/Serie: Proc. SPIE 6112, Microfluidics, BioMEMS, and Medical Microsystems IV, 611206
We present the fabrication and characterization of single mode waveguides fabricated monolithically in SU-8. SU-8 is a negative resist, which can be structured by UV lithography followed by a baking step to induce cross-linking. As a material platform, SU-8 is well suited for systems used for biochemical analysis, as it possesses very high chemical resistance and good mechanical stability. Here we show that single mode embedded waveguides can be fabricated using SU-8 as core material and the modified SU-8, mr-L 6050XP, as cladding material. The refractive index difference between the two materials of the final waveguides is around 0.004. All waveguides fabricated in this work have a height of 4.5 μm and their widths are 3, 5 or 10 μm. We have characterized the losses of these waveguides with the cut-back method both at 635 nm and 1535 nm. We have furthermore studied changes in the refractive index of the material with changes in the processing of the SU-8 material. Finally, absorption measurements in the visible spectral range and mode profile analysis have also been performed. Because of the low optical absorption at wavelengths above 700 nm in combination with the fast, simple and cost-efficient fabrication process, we show that SU-8 is well suited as structuring material for waveguides for integrated optics.
- Technology and Engineering
San Jose, CA