Takehiro Taniguchi

Monolithic integrated-optic position/displacement sensor using waveguide gratings and QW-DFB laser

A monolithic fully-integrated interferometer position/displacement sensor is proposed. The device is implemented with waveguide grating components, a GRIN SCH SQW DFB laser and photodiodes. A prototype device of 6.5/spl times/2.0 mm/sup 2/ chip size and 0.4/spl times/0.4 mm/sup 2/ sensing beam aperture is fabricated, and the sensor operation of submicron resolution is demonstrated.<<ETX>>

Monolithic integration of waveguide gratings and quantum-well distributed-feedback laser for implementation of subminiature optical-disc pickup head

We propose a subminiature optical-disc pickup head implementation by monolithic integration of wave- guide grating components, a graded-index separate-confinement heterostructure single-quantum-well distributed-feedback laser and photodiodes. Fabrication of a prototype device and the results of a preliminary experiment are presented.

A Monolithic Confocal Laser Coupler For an Optical Pick-up.

We propose a novel optical pick-up using a confocal laser coupler for an optical disk player. The laser coupler consists of a glass window and a monolithic optical element which includes a laser diode, 8 photodiodes, and a pyramid-shaped prism mirror positioned near the confocal plane which acts as a knife edge and a photo-coupler. The focusing-error signal is detected using the confocal knife edge (CKE) method and the tracking-error signal is detected using the CKE push-pull method. The jitter of Compact Disc (CD) readout was 6.7 ns at a line velocity of 1.2 m/s, and the DC offsets of the tracking-error signal were sppressed to less than 1/3 for a radial lens displacement of ±400 µm compared to the conventional push-pull method.

Integration of Laser Diodes and Photodiodes in Photonic Integrated Circuit for Measurement

Fully integrated PICs for measurement have been successfully fabricated for the first time. The device is implemented with waveguide grating components, a GRIN-SCH-SQW-DFB LD and PDs. Special care is taken to prevent direct optical coupling between integrated LDs and PDs in order to detect feeble sensing light. An interference signal is actually detected as photocurrent modulation of ?1-nA amplitude by this integrated structure.