Nobuhiko Kanbara

MEMS Tunable VCSEL with Concave Mirror using the Selective Polishing Method

We have proposed a micromachined tunable vertical cavity surface emitting laser fabricated using the selective polishing method and two chip bonding. The MEMS-VCSEL consists of a micromachined SOI substrate with concave figure and a half VCSEL chip. The MEMS chip and the half VCSEL chip are bonded together with a narrow gap between them using the metal thermo compression bonding method. Wavelength tuning is achieved electrostatically by applying voltage between silicon membrane and silicon substrate. We have obtained wide tuning range without a mode-hop and sidemode suppression are about 32 nm and 40 dB respectively

Wavelength modulation over 500 kHz of micromechanically tunable InP-based VCSELs with Si-MEMS technology

Wavelength modulation over 500 kHz by a micromechanically tunable vertical-cavity surface-emitting laser (VCSEL) consisting of an InP-based half-VCSEL chip and a micromachined silicon-on-insulator chip with a concave movable mirror has been demonstrated for the first time. A peak power of 3.5 mW, a tuning range of 55 nm, and a side-mode suppression ratio of about 60 dB have been demonstrated.

Antenna-coupled rectifying diode for IR detection

An antenna-coupled rectifying SChottky Barrier DIode (SBD) for IR detection is fabricated on Si by IC processes. Aluminum thin film antenna of 30 micrometers length and 1.5 micrometers width is formed on thermally grown SiO2 layer on Si. At the end of antenna, rectifying SBD of 0.03 micrometers diameter is formed by focused ion beam (FIB) milling technique. Ion current monitoring system with FIB largely reduced the size of milled hole, which is conventionally limited by ion beam waist diameter. IR radiation from CO2 laser of 10.6 micrometers in wavelength and 0.55 W in power is used for device evaluations. Signal dependence on incident angle of CO2 laser radiation and dependence on diode bias voltage are evaluated. We confirmed the rectifying operation of antenna- coupled SBD at IR region and experimentally obtained rectified voltage of 173 nV. The NEP is calculated to be 1.94 X 10-6 W/Hz-1/2.