Wafer-Fused Optoelectronics for Switching
CALIFORNIA UNIV SANTA CRUZ SCHOOL OF ENGINEERING
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Wafer fusion technique for realization of compact waveguide switches and three-dimensional 3-D photonic integrated circuits is investigated theoretically and experimentally. Calculations based on beam propagation method show that very short vertical directional couplers with coupling lengths from 40 to 220 micrometers and high extinction ratios from 20 to 32 dB can be realized. These extinction ratios can be further improved using a slight asymmetry in waveguide structure. The optical loss at the fused interface is investigated. Comparison of the transmission loss in InGaAsP-based ridge-loaded waveguide structures with and without a fused layer near the core region, reveals an excess loss of 1.1 dBcm at 1.55 micrometers wavelength. Fused straight vertical directional couplers have been fabricated and characterized. Waveguides separated by 0.6 micrometers gap layer exhibit a coupling length of 62 micrometers and a switching voltage of about 2.2 V. Implications for GaAs-based fused couplers for 850 nm applications will also be discussed.
- Electrooptical and Optoelectronic Devices