We propose and demonstrate a new stacked packaging structure using silica-based planar lightwave circuits (PLCs) with integrated micro-mirrors. This structure enables us to integrate active devices on PLCs with certain flexibility as regards optical coupling design and device selection. To achieve this, we developed an integrated micro-mirror with an accurate reflection angle and shielding structures to prevent crosstalk, and successfully demonstrated an 8-channel photodiode array module with excellent characteristics consisting of a high responsivity of > 0.85 A/W and a low crosstalk of < -65 dB.

Small-size directional coupler type optical multi/demultiplexers using high refractive-index-difference composite-glass waveguides have been investigated. A novel design to minimize wavelength response sensitivity to waveguide width deviation in the coupler part was proposed. Composite glass waveguides with 5% were fabricated using Corning 7059 glass for the core and SiO2 for the cladding. 1.3/1.55-µm optical multi/demultiplexers with short coupler length of 300 µm, low insertion loss of 5 dB and high crosstalk attenuation of more than 25 dB were realized.