Microcavity physics and design will be reviewed. Following an overview of applications in quantum optics, communications and biosensing, recent advances in ultra-high-Q research will be presented.

Optical microcavities

An interference modulator (Imod) incorporates anti-reflection coatings and/or micro-fabricated supplemental lighting sources. An efficient drive scheme is provided for matrix addressed arrays of IMods or other micromechanical devices. An improved color scheme provides greater flexibility. Electronic hardware can be field reconfigured to accommodate different display formats and/or application functions. An IMod's electromechanical behavior can be decoupled from its optical behavior. An improved actuation means is provided, some one of which may be hidden from view. An IMod or IMod array is fabricated and used in conjunction with a MEMS switch or switch array. An IMod can be used for optical switching and modulation. Some IMods incorporate 2-D and 3-D photonic structures. A variety of applications for the modulation of light are discussed. A MEMS manufacturing and packaging approach is provided based on a continuous web fed process. IMods can be used as test structures for the evaluation of residual stress in deposited materials.

Photonic mems and structures

We provide the first experimental observation of structure tuning of the electromagnetically induced transparencylike spectrum in integrated on-chip optical resonator systems. The system consists of coupled silicon ring resonators with $10\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ diameter on silicon, where the coherent interference between the two coupled resonators is tuned. We measured a transparency-resonance mode with a quality factor of 11 800.

Experimental realization of an on-chip all-optical analogue to electromagnetically induced transparency

Micro-ring wavelength filters and resonant modulators using polymer materials at 1300 nm and 1550 nm are analyzed, designed, and demonstrated. The rings are integrated with vertically coupled input and output waveguides. The devices are fabricated using optical lithography. Filters with a finesse of 141 and free spectral range of 5 nm at 1300 nm and finesse of 117 with a free spectral range (FSR) of 8 nm at 1550 nm are demonstrated. Ring resonators with a Q as high as 1.3 /spl times/ 10/sup 5/ at 1300 nm are demonstrated. The filters can be temperature tuned at the rate of 14 GHz//spl deg/C. Resonant ring modulators, which use an electrooptic polymer, are demonstrated. The resonance wavelength voltage tunes at the rate of 0.82 GHz/V. The modulators have a bandwidth larger than 2 GHz. Using the resonant modulator, and open eye diagram at 1 Gb/s is demonstrated.

Polymer micro-ring filters and modulators

We review photonic applications of dielectric whispering-gallery mode (WGM) resonators-tracing the growth of the technology from experiments with levitating droplets of aerosols to ultrahigh-Q solid state crystalline and integrated on-chip microresonators.

Optical resonators with whispering-gallery modes-part II: applications

Air-clad glass microring resonators vertically coupled to buried channel waveguides are experimentally investigated. Ring radii of 10 /spl mu/m, and channel drop bandwidths of 5 nm are reported. Vertical coupling eliminates the need for the etching of fine features, and relaxes the alignment of the resonator with respect to the input and output bus waveguides.

Vertically coupled glass microring resonator channel dropping filters

An eight-channel add-drop cross-grid vertically coupled microring resonator (VCMRR) filter is proposed and demonstrated. The cross grid comprises a grid-like array of buried channel waveguides which perpendicularly cross through each other, VCMRRs at each of the cross-grid nodes serve as the wavelength selective add-drop filters. Measured crosstalk levels at the crossings are typically less than -30 dB. Rings with a nominal radius of 10 /spl mu/m are used to achieve a free-spectral range of 20 nm and optical bandwidths of 1 nm, while changes of the radii in increments of 50 nm lead to a nominal channel spacing of 5.7 nm.

An eight-channel add-drop filter using vertically coupled microring resonators over a cross grid

The analytic theory governing the complete scattering response of two-dimensional (2-D) microring resonator arrays is developed, The method is applicable to arbitrary interconnections of general four-port, single polarization nodes. An 8/spl times/8 cross-grid array of vertically coupled glass microring resonators is fabricated for test purposes.

Microring resonator arrays for VLSI photonics

Growth of structure-controlled polycrystalline silicon ingots for solar cells by casting

Ring resonators are coupled in parallel in order to obtain a second order type of wavelength response. The phase relationship between the rings determines the details of the spectral response. The rings used in the experiment have radii of 25 /spl mu/m and are fabricated from compound glass having an index of 1.539. Several resonances are observed to have double peaked box-like response.

Wugen Pan

Papers

Vertically coupled glass microring resonator channel dropping filters

An eight-channel add-drop filter using vertically coupled microring resonators over a cross grid

Microring resonator arrays for VLSI photonics

Growth of structure-controlled polycrystalline silicon ingots for solar cells by casting

Second-order filter response from parallel coupled glass microring resonators