Enhancement of the evanescent field using polymer waveguides fabricated by deep UV exposure on mesoporous silicon

Abstract

Polymer integrated reverse symmetry waveguides on porous silicon substrate fabricated by using deep ultraviolet radiation in poly(methyl methacrylate) are presented. The layer sequence and geometry of the waveguide enable an evanescent field extending more than 3 microm into the upper waveguide or analyte layer, enabling various integrated optical devices where large evanescent fields are required. The presented fabrication technique enables the generation of defined regions where the evanescent field is larger than in the rest of the waveguide. This technology can improve the performance of evanescent-wave-based waveguide devices.

Wide-Range Refractometric Sensor Using Differently Sensitive Y-Branched Waveguides

“…They are supposed to be birefringent to obtain unequal sensitivities, since the sensitivity of the waveguide is dependent on the thickness of the high-index overlay due to the presence of an activated evanescent field. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] The effect of the TiO 2 film thickness on the sensitivity was numerically investigated, and the obtained results are plotted in Fig. 2.…”

Refractometric Sensor Based on a Birefringent Silica Waveguide Using a Tapered Cladding

“…[7][8][9] Its performance has been drastically upgraded by attaching a high-index film to conventional silica/polymer waveguides, since the interaction between the evanescent field of the guided mode of the waveguide and the analyte could be reinforced. [10][11][12][13][14][15][16][17][18][19][20][21][22] The high-index film was previously deposited directly on the waveguide core and tapered in such a way that only the sensing region at the center is covered with the film, while the input and output sections thereof are not. In this way, the loss resulting from the mode mismatch between the sensing region and the input/output regions was reduced.…”