Dave Gill

Very high-order microring resonator filters for WDM applications

High-order microring resonators having from 1 to 11 coupled cavities are demonstrated. These filters exhibit low loss, flat tops, and out-of-band rejection ratios that can exceed 80 dB. They achieve performance that is suitable for commercial applications.

Optical sensing of biomolecules using microring resonators

A biosensor application of vertically coupled glass microring resonators with Q/spl sim/12 000 is introduced. Using balanced photodetection, very high signal to noise ratios, and thus high sensitivity to refractive index changes (limit of detection of 1.8/spl times/10/sup -5/ refractive index units), are achieved. Ellipsometry and X-ray photoelectron spectroscopy results indicate successful modification of biosensor surfaces. Experimental data obtained separately for a bulk change of refractive index of the medium and for avidin-biotin binding on the ring surface are reported. Excellent repeatability and close-to-complete surface regeneration after binding are experimentally demonstrated.

Tunable bandwidth microring resonator filters

Tunable bandwidth, tunable line-shape filters are realized by incorporating Mach-Zehnder interferometers as directional coupler elements within higher order microring resonators. A flat-top bandwidth tuning range of 2.7 GHz to 21 GHz is demonstrated.

Microring resonators: the promise of a powerful biochemical sensor platform

Microring resonators constitute ideal microspots where the target reaction are spatially confined and exhibit high signal density. These devices have very high quality factors, Q up to 10/sup 8/ which translates to enhanced sensitivity and signal-to-noise ratio. The combination of high Q and small geometry leads to significant power buildup within the microcavity and can allow the accurate detection of very few molecular events on the ring surface. We have designed and fabricated devices with different geometries and optimized operational wavelength ranges. In addition to high volume microfabrication, Hydex/sup /spl trade// allots us to functionalize the ring using established immobilization protocols for antibodies, nucleic acids, receptors and artificial sensing layers. Preliminary testing used the well documented and versatile biotin-avidin complex to immobilize an antibody biofilm. With Hydex/sup /spl trade// we can design highly-sensitive, readily portable label-free and reagent-free assays.

Advanced photonic integration and high-index-contrast circuit

We highlight recent advances in advanced photonic integration of reliable densely integrated photonic integrated circuits (PIC) and high-index-contrast photonic lightwave circuits (PLC). The applications and benefits of these devices will be presented.

High index contrast photonics platform

A new low-loss high-index-contrast photonics platform has been developed for integrated optics and microwave photonics. The platform consists of a material system that has an index contrast that is adjustable from 0 to 25% and which is processed using conventional CMOS tools. The platform allows one to four orders of magnitude reduction in the size of optical components compared with conventional planar technologies. As an example, meter long path lengths occupy coils that are millimeters in diameter. Microwave photonic building blocks that are enabled include large bit count programmable delay lines for beam steering and shaping that fit in less than a square centimeter and which have delays controllable from 5 fsec to 10 nsec. Also enabled are arrays of high order tunable filters, a hundred micrometers in size, having linewidths ranging from tens of MHz to tens of GHz. These filters can be tuned over several hundred GHz, and when placed in Vernier architectures can be tuned across the C band (5 THz). An optical chip typically consists of dozens of optical elements. Each element is placed in its own micro-control loop that consists of a thin film heater for thermo-optic control and a thermistor for electronic feedback. The micro-control loops impart intelligence to the optical chip.

Large-scale high-index-contrast planar lightwave circuits

Large scale optical integration is enabled by high index contrast materials and building blocks. We highlight recent advances in the miniaturization of optical elements and of dense integration of planar lightwave circuits for telecommunications and RF photonic applications.

Advanced Ring Resonator Based PLCs

Microring resonators are finding increasing use in commercial applications. We highlight the theory of microrings, their fabrication, and a summary of microrings in commercial use, including tunable filters, dispersion compensators, and OCDMA coders

Integrated polarimeter assisted ring scanning spectrometer

Three-stage Vernier, 3rd order lattice ring filters are implemented to realize a full C-band spectrometer. A polarization controller is also integrated for ldquosplit and fliprdquo operation.