Lasing behavior of a single-transverse-mode vertical-cavity surface-emitting laser (VCSEL) was observed while the polarization direction of an optical feedback was rotated. Optical powers of two polarization modes of a VCSEL showed sinusoidal dependences on the polarization-rotation angle. The power variation was seen when an optical feedback ratio was larger than -20 dB, though the variation depth dropped suddenly as the feedback ratio became smaller than -25 dB. An in-line type rotation sensor utilizing this behavior is proposed. The sensor system was constructed and the detection principle was demonstrated.

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Silicon dioxide is transparent in wavelength down to vacuum UV, and high quality film is obtained by thermal oxidation of Si substrate. Both of higher-refractive-index guiding core and lower-index optical buffer layers consist of SiO2 films thermally-grown at different temperatures on Si substrate. Silicon-on-insulator wafer, of which buried oxide layer of 3 µm thickness had been treated at >1100°C to be optical buffer layer, was held in steam flow at 800°C for oxidizing top Si layer to form SiO2 guiding core layer of 1.2 µm thickness. Guiding characteristics were measured and showed good agreement with theoretical prediction.

Emission intensity patterns and spectra of a two-transverse-mode vertical-cavity surface-emitting laser (VCSEL) were observed and measured while the position and polarization of an optical feedback light were controlled. Lasing behavior was discussed in relation to linear polarization modes. The observed emission point shift with unchanged wavelengths was explained by the superposition of two newly appeared modes.

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