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We propose a two-ring structure that can generate an ultra-narrow resonance which may be used, together with the Mach-Zehnder interferometer (MZI), to engineer bistability switching with low switching threshold and reasonably high extinction ratio (ER) and modulation depth (MD). The two-ring MZI (2RMZI) is also compared with the conventional one-ring MZI (1RMZI). A flexible optimization scheme has been developed and can be used to obtain maximum ER and MD. Complementary relationship between switching threshold, sensitivity to loss and optical bandwidth are discussed for the two types of devices.

This paper reports a sandwiched droplet resonator for low concentration protein detection using microfluidic chip (MFC). The droplet resonator integrated onto a single microfluidic chip consists of a sandwiched droplet and two optical fiber tapers that are directly placed into the droplet. The concentration measurement of protein is based on the shift of the resonant modes in the droplet resonator. The advantages of the resonator are the high quality factor (104 to 108), easy integration and no contamination, which promise the high accuracy (10-5 to 10-9 g/mL) measurement of protein concentration and label-free biosensing on the microfluidic chip.

Micro-cavity structure composed of silicon wire with 240 nm square cross section and two symmetrical sidewall waveguide Bragg gratings is fabricated and studied for the operation under telecommunication wavelengths. Optical filter of quasi-TE mode was realized based on this cavity. In such micro-cavity, optical quality factor (Q) was measured up to 380 with a 4.8 nm free spectral range (FSR) and 12 dB fringe contrast (FC). The measured group index of silicon waveguide with only 240 nm square cross section was between 3.80 and 5.43. It is the first time group delay of silicon wire waveguide with such small core dimension is studied. Larger group delay can be expected after optimizing the design parameters and the fabrication process.

There is a recent trend to reduce waveguide based silicon photonic devices to the sub-micron regime for increased chip density and better cost efficiency. However, designing polarization independent (PI) ring resonator using submicron waveguide is a challenge as it exhibits strong polarization dependency. We demonstrate theoretically the feasibility of realizing both single-mode (SM) and PI operation in ring resonator based on sub-micron silicon-on-insulator (SOI) rib waveguides. A resonance spectra misalignment that represents only 11% of the full-width half-maximum (FWHM) linewidth of 1.64 nm is achieved, with a free spectra range of 13 nm.

We show experimentally the existence of defect modes in mutually coupled microring resonator array fabricated in silicon-on-insulator technology. The movements of donor-like and acceptor-like modes are demonstrated for various defect lengths and in a good agreement with earlier theoretical prediction.

Designing polarization independent (PI) ring resonators using submicron waveguides is a challenge as they exhibits strong polarization dependency. We demonstrate theoretically the feasibility of realizing single-mode and PI ring resonator on submicron SOI rib waveguides.

We propose and demonstrate a simple one-bus two-ring configuration where the two rings are mutually coupled that has advantages over the one-ring structure. Unlike a one cavity system, it can exhibit near critically-coupled transmission with a broader range of loss. It can also significantly enhance the cavity finesse by simply making the second ring twice the size of the bus-coupled one, with the enhancement proportional to the intensity buildup in the second ring. A ring structure with high finesse has many potential applications, one of which, in bistability switching, is discussed.

We show theoretically and demonstrate experimentally that box-like response can be obtained using 2D arrays of microring resonator. The box-like response is manifested from the complementary photonic bandgap properties of the column and row configurations. The observed sidelobe suppression is ~10 dB, while the usable bandwidth can be as high as 500 to 750 GHz.

A 1 times 2 and 1 times 3 planar optical splitter based on BenzoCyclobutene (BCB 4024-40) polymeric material is proposed. The device is designed based on symmetric interference mechanism, utilizing a BK7 glass as a substrate and thin layer of SiO2 as a cover. Simulation results show that the splitting uniformity is better than 0.5 dB at 1550 nm optical wavelength.

We show that a general 2-D resonator lattice can approximate an ideal bandpass filter, fundamentally because the 2-D periodic structure exhibits non-overlapping photonic bandgaps.

Diode-pumped, Q-switched single-frequency microchip lasers are compact and simple solid-state lasers that can provide high peak powers with a diffraction-limited output beam.