Single-channel laser Doppler vibrometers integrated on silicon-on-insulator (SOI)

Multi-location velocity measurements of a vibrating surface are of interest recently. By scanning the laser beam of a single-point laser Doppler vibrometer (LDV) across the surface of interest, one can realize the multi-location vibration measurement. However, the recovered velocity values of different locations are not obtained at the same time. In many applications, such as measuring the aortic pulse wave velocity, simultaneous velocity measurements for different locations are required. Multi-channel LDVs can be used in this case, in which multiple laser beams are generated and sent to the surface of interest simultaneously. However, the complexity of realizing the multiple interferometers in a bulk LDV system will increase as the number of channels increases, and thus it is very hard to realize a bulk LDV with many channels We propose to use the silicon-on-insulator (SOI) chip as a platform of the multi-channel interferometers. With the help of silicon photonics and CMOS technology, multiple interferometers can be miniaturized and fabricated on SOI chips. Laser beams are sent into or out of the chip through optimized on-chip grating couplers, with the coupling insertion loss of less than 2 dB per coupler. The total footprint of the integrated multiple interferometers can be very small (several square of millimetres) compared to a bulk LDV system. The cost of the chips will be dramatically decreased for mass production. Additionally, the stability of the integrated interferometers is much better than that of the interferometer built with discrete optical components

Low dispersion integrated michelson interferometer on silicon on insulator for optical coherence tomography

We present an integrated silicon Michelson interferometer for OCT fabricated with wafer scale deep UV lithography. Silicon waveguides of the interferometer are designed with GVD less than 50 ps/nm. km. The footprint of the device is 0.5 mm x 3 mm. The effect of sidewall roughness of silicon waveguides has been observed, possible solutions are discussed

Absorption spectroscopy of glucose based on a silicon photonics evanescent sensor

We present a silicon photonics evanescent sensor for glucose absorption spectroscopy. The important design aspects of this miniature sensor are discussed as well as the experimental challenges. We demonstrate detection of glucose down to 14 mmol/L, close to the physiological range of blood glucose in humans