Optical sensing

Monolithic construction of optical interferometer is an excellent solution for measurement stabilization as well as for device miniaturization. The whole heterodyne interferometer optics for measurement of verocity and displacement was integrated on a LiNbO3 chip pigtailed with a probing fiber. We demonstrated sensing heads by integrating grating components and photo- and/or laser-diodes on Si and GaAs substrates for position/displacement sensing. Grating couplers play important roles in the devices and various types were discussed and designed. A confocal scanning optical grating microscope was also constructed by integrating components on Si substrate.

Fig.6 Photodiode array in the IO parallel data pickup device.

Fig.7 IO device for laser Doppler velocimeter.

Fig.8 IO device for 2-D displacement sensing.

Fig.9 Microphotographs of grating components and photodetectors integrated on the 2-D displacement sensor.

Fig.10 High efficiency 3rd order grating coupler.

Fig.11 An object (IC) image obtained with IO scanning optical microscope head.