Kimizo Ono

Fiber optic reflectance spectrophotometry system for in vivo tissue diagnosis.

Fiber optic probes for a small portable reflectance spectrophotometry system for noninvasive clinical diagnosis have been developed. A slender fiber optic probe, 3 m long, 2.4-mm diameter, which goes into the channel of a fiber optic endoscope, has been developed as the standard probe. To expand the availability and capability of this reflectance spectrophotometry system, some variations of the fiber optic probes were developed: contact sensor, pressure sensor, attachments for dental use, and a modified-shape probe head for continuous monitoring. The feasibility of these fiber optic probes was examined experimentally.

Growth of AlInAs and heterostructures on InP by OMVPE

Abstract AlInAs epilayers and GaInAs/AlInAs quantum well structures were grown on InP substrates by organometallic vapor phase epitaxy (OMVPE) using trimethylaluminum, trimethylindium, triethylgallium and arsine in a vertical reactor at reduced pressure. A smooth and flat surface was achieved at a substrate temperature of around 650°C. From double crystal X-ray rocking curves, a narrow linewidth of 24 arc sec was obtained from a 1 μm thick AlInAs epilayer, where that of the InP substrate was 14 arc sec. The variation of the lattice mismatch of the AlInAs epilayer with respect to the InP substrate was less than 5 × 10 −4 across a 2-inch diameter substrate. In photoluminescence (PL) measurements at 4.2 K, an excitonic transition with a linewidth of 12 meV was observed from the AlInAs epilayer grown at 650°C with a high V/III ratio of 225. This linewidth is the narrowest ever reported for the AlInAs epilayer grown by OMVPE. We also observed a strong and narrow emission from PL measurements for a GaInAs/AlInAs single quantum well as thin as 6 A with an energy shift of 645 meV from a GaInAs bulk bandgap at 4.2 K. Further, we obtained an excellent uniformity of single quantum wells evaluated by PL peak energy fluctuation across a 2-inch diameter substrate. In the doping study for AlInAs epilayers using disilane, an improved doping efficiency was achieved at a higher V/III ratio. The doping efficiency in AlInAs had a larger dependence on the substrate temperature than that in GaAs.

Phase-modulated fiber optic gyroscope with wide dynamic range and linear scale factor

An open-loop phase-modulated fiber optic gyroscope with a wide dynamic range and linear scale factor is described. The optical Sagnac phase shift is transposed into an electrical phase shift by introducing two phase sensitive detectors and two electronic amplitude modulators with independent carrier frequency from the optical phase modulation. Preliminary experiments show good linearity over a wide dynamic range up to 1000 degrees /s and verifies the theoretical prediction.

Concave mirror laser beam waveguide for a carbon dioxide laser surgery system

An improved articulated laser beam waveguide with seven mirrors was developed for a carbon dioxide laser surgery system. Four concave mirrors were introduced to suppress the accumulating off-axis error and to control the beam diameter of the propagating laser beam. Each curvature of the concave mirror was determined to be optimum according to the calculation of off-axis errors and Gaussian beam parameters of the propagating laser beam. An experiment demonstrated the merits of introducing the concave mirrors according to the proposed design procedure.