We have proposed a vertical comb-drive MEMS mirror which can be applied for a spectrometer with a phase-shifting method, and fabricated the mirror device using the micro fabrication technology. The configuration of the MEMS mirror was designed with three vertical electrostatic comb-drive actuators and hinges at the periphery of the mirror. In the proposed spectrometer, the phase of the light which is reflected at the movable mirror is changed, and the interferogram is obtained by the movable mirror which is driven precisely. We evaluated the moving characteristics of the fabricated MEMS mirror and confirmed that the MEMS mirror could be driven vertically to about 23μm and also could be tilted. Using this MEMS mirror, we configured the spectrometer with a source of monochromatic light (λ= 405 nm), and evaluated the spectroscopic characteristic in principle. Then, we have confirmed that the fabricated MEMS mirror can be applied to the spectrometer with the phase-shifting method.

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This paper describes the result of low-temperature direct bonding of vertical-cavity surface-emitting lasers (VCSELs) by Au-Au surface-activated bonding (SAB). Flip-chip mountable VCSELs (250 μm × 250 μm × 100 μm thick) with anode and cathode on the same side of each chip were used for the experiments. After organic contaminants on the Au surfaces of the VCSELs and silicon substrates were removed by surface activation with argon radio-frequency plasma, Au-Au bonding was carried out by contact in ambient air with applied static pressure for 30 s. The die-shear strength and light intensity-current-voltage (L-I-V) curves were measured to evaluate the mechanical and optoelectronic characteristics of bonded VCSELs. The high die-shear strength of over 50 gf (54 MPa: shear force divided by the total electrode pad area) was achieved at a relatively low bonding temperature of 150°C and a contact load of 500 gf. The L-I-V measurements showed that the bonded VCSELs at the bonding temperature of 150°C functioned normally without degradation.

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A triangulation distance sensor is constructed bending the wafer with metal hinges. On the Si wafer, elements are pre-aligned at the planer condition using the photolithography. The position sensitive detector (PSD), mirror, and alignment pit for a ball lens are prepared. 3-sensor array is integrated in 20×17×10 mm³ size. Compared with our previous study using polymer, the metal hinge stabilizes the long-term performance and the process. Optical elements including LD chip are all included on the wafer. The demonstrated measurement range is 18-40 mm.

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The rapid increase in the recording density of hard disk drive (HDD) has required a significant decrease in the flying height of sliders. The active-head slider technology for HDD is one of the most promising means to decrease flying height. This paper describes a piezoelectric flying height control (PFC) slider which has a faster dynamic response compared with conventional active-head sliders. This slider can be also adapted to the conventional slider-fabrication process. PZT layer located near the magnetic head has shear mode deformation by applying electric voltage between the upper and lower electrodes when the flying height of magnetic head needs to be decreased or increased. We fabricated a prototype with single crystal Si substrate for feasibility study. Our evaluation of the prototype revealed that the piezoelectric constant of the shear mode deformation was 0.88 nm/V, and the first resonant frequency was 50 kHz. The shape of the air bearing surface (ABS) was optimized by simulations using a robust design method. We found that the stroke was 8 nm for an applied voltage of 11 V if the flying height was 11nm.

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We developed a high-resolution Michelson interferometer in order to stabilize the relative phase of double pulses by using a He-Ne two-frequency laser positioning system. Very stable phase-locked pulse pair whose phase difference was only 4 degree at 900nm was realized.
Using a high-resolution Michelson interferometer, we demonstrated coherent control of an exciton in a GaAs/AlGaAs crescent-shaped quantum wire. The dephasing time of the single quantum wire was 400fs.

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