NOVEL MICROMIRROR FOR VERTICAL OPTICAL-PATH CONVERSION FORMED IN SILICA-BASED PLC USING WETTABILITY CONTROL OF RESIN

A novel technique has been developed for fabricating a micromirror in a single-mode silica-based planar lightwave circuit (PLC), in which th e flat slope for the mirror is made of resin by utilizing wettability control and the surface tension effect. It was shown that the mirror c ould be designed by numerical calculation based on the equation of You ng and Laplace for a liquid surface. A controllable mirror angle range from 30 to 60 degrees was achieved experimentally by changing the pos ition of the boundary line between high and low wettability regions us ing oblique evaporation. The characteristics of a fabricated 45 degree s mirror installed in a silica-based PLC were evaluated by coupling it vertically to a single-mode fiber. The obtained coupling losses betwe en waveguides and a fiber were 0.60-1.15 dB for mirrors with widths of more than 200 mu m, and 0.92-1.62 dB for 190 mu m wide mirrors, at a wavelength of 1.55 mu m. The experimental minimum losses of 0.6 and 0. 92 dB coincided with the calculated values.