Pengqin Wu

Tunable Optical Ring Resonator Integrated With Asymmetric Mach–Zehnder Interferometer

We demonstrate theoretically a tunable optical ring resonator incorporating an asymmetric Mach-Zehnder interferometer (MZI) and two phase shifters. The optimal resonance state of the ring resonator with different geometries can be achieved by tuning the two embedded phase shifters. Distinct intensity and phase responses and transmission spectra characteristics are newly observed by setting different structural parameters such as the asymmetrical path lengths of the waveguides and the coupling ratio of the directional couplers in the MZI. The performance characteristics related to the radius of the ring cavity and the propagation losses in the waveguides are also discussed. At optimal resonance, it is shown that sharp intensity response and tunable narrow-bandwidth spectra can be achieved especially for resonators with a highly asymmetrical configuration. Such device has a potential in sensing, switching and filtering applications.

Resonant frequency shift characteristic of integrated optical ring resonators with tunable couplers

Ring resonators integrated with tunable couplers are useful devices in integrated optics systems. The resonant frequency shift characteristic of tunable resonators is theoretically analyzed. It is shown that the resonant frequency shift range is dependent on the configurations and tuning methods of couplers. It provides an analytical explanation of the frequency shift effect by the phase transmission method and the coupled-mode theory (CMT) of asymmetric waveguides. Optimized designs of different kinds of tunable couplers are discussed in order to improve the resonant frequency stability. Moreover, the intensity–phase relationship induced by the resonant frequency shift effect is also discussed, and a more efficient configuration of optical sensors using phase modulation is proposed.

Simulation of an optical accelerometer based on integrated optical ring resonator

Tight, integrated accelerometers are current interests in Micro-Opto-electro-Mechanical-Systems (MOEMS). An optical accelerometer based on a novel integrated optical resonator is proposed. The transmission spectra and the relation between the structure parameters and the device sensitivity are simulated. This ring resonator structure shows great potential to develop high sensitive accelerometers.

An experimental study of the fabrication of polycarbonate optical waveguides

A novel polycarbonate (PC) was introduced to apply in the optical waveguide devices. PC has following distinct merits than common polycarbonate: good processability, high thermal stability up to 293 C°; and high optical transparency. Optical properties of absorption behavior and propagation loss were investigated in slab waveguides, and low propagation losses of 0.335 dB/cm (@1550nm) and 0.197 dB/cm @632.8nm) have been achieved by using prismcoupler. Additionally, straight optical waveguide and MMI coupler of ring resonator were fabricated using ultraviolet (UV) cured resin Norland optical adhesive 61 (NOA61) as under or upper cladding layer and polycarbonate as waveguide core-layer material through conventional methods such as spin coating, photolithography and reactive ion etching (RIE). The process was studied in detail and the experimental results were given.

Tunable microring resonator based on dielectric-loaded surface plasmon-polariton waveguides

A ultrasmall thermal tunable ring resonator based on plasmon-polariton waveguide is theoretically analyzed. The thermooptic coefficient and the temperature-dependent amplitude attenuation coefficient of the effective mode index of the plasmonic waveguide are calculated by finite element method (FEM), and the transmission characteristics of the ring resonator with different structural parameters are investigated. Such device shows high efficient tunability and may be utilized to develop novel tunable plasmonic devices.

A novel thermal controlled optical attenuator

A novel thermal controlled optical attenuator based on symmetric dielectric-loaded surface plasmon polariton (SDLSPP) waveguide is proposed and theoretically analyzed in this work. The mode effective indices, propagation lengths, the temperature dependent characteristic are analyzed using a fininte-element method (FEM). Such device can be controlled by low driving power and shows excellent tunability. The optical attenuator provides a potential for novel temperature-tunable surface plasmon polariton (SPP) devices.