Shin-ichirou Tezuka

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.

Analysis and Experiments for Evaluating Adhesion of Arbitrary-Shaped Microstructures using Optimization Method

An important design consideration is to avoid the adhesion of microstructures. This report proposes an optimization method for evaluating the adhesion of microstructures of arbitrary shape by minimizing the total energy of the system, and shows the method of evaluating surface energy γ S from experimental results. By this method, it is possible to calculate γ S from one adhesion sample, and to analyze the adhesion of other arbitrary-shaped structures. In this report, the adhesion analysis of square plates were carried out, and the calculation of γ S showed good agreement with the result of Mastrangelo’s apploximation formula of the square plate [1] within 30%.