Dim-Lee Kwong

Publications

2 Silicon-Waveguide Based Silicide Schottky- Barrier Infrared Detector for on-Chip Applications

Authors: Guo-Qiang Lo, Shiyang Zhu, Dim-Lee Kwong

Abstract:

We prove detailed analysis of a waveguide-based Schottky barrier photodetector (SBPD) where a thin silicide film is put on the top of a silicon-on-insulator (SOI) channel waveguide to absorb light propagating along the waveguide. Taking both the confinement factor of light absorption and the wall scanning induced gain of the photoexcited carriers into account, an optimized silicide thickness is extracted to maximize the effective gain, thereby the responsivity. For typical lengths of the thin silicide film (10-20 Ðçm), the optimized thickness is estimated to be in the range of 1-2 nm, and only about 50-80% light power is absorbed to reach the maximum responsivity. Resonant waveguide-based SBPDs are proposed, which consist of a microloop, microdisc, or microring waveguide structure to allow light multiply propagating along the circular Si waveguide beneath the thin silicide film. Simulation results suggest that such resonant waveguide-based SBPDs have much higher repsonsivity at the resonant wavelengths as compared to the straight waveguidebased detectors. Some experimental results about Si waveguide-based SBPD are also reported.

Keywords: Silicon Photonics, Infrared detector, Schottky-barrier, Silicon waveguide

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1798
1 CMOS-Compatible Silicon Nanoplasmonics for On-Chip Integration

Authors: Guo-Qiang Lo, Shiyang Zhu, Dim-Lee Kwong

Abstract:

Although silicon photonic devices provide a significantly larger bandwidth and dissipate a substantially less power than the electronic devices, they suffer from a large size due to the fundamental diffraction limit and the weak optical response of Si. A potential solution is to exploit Si plasmonics, which may not only miniaturize the photonic device far beyond the diffraction limit, but also enhance the optical response in Si due to the electromagnetic field confinement. In this paper, we discuss and summarize the recently developed metal-insulator-Si-insulator-metal nanoplasmonic waveguide as well as various passive and active plasmonic components based on this waveguide, including coupler, bend, power splitter, ring resonator, MZI, modulator, detector, etc. All these plasmonic components are CMOS compatible and could be integrated with electronic and conventional dielectric photonic devices on the same SOI chip. More potential plasmonic devices as well as plasmonic nanocircuits with complex functionalities are also addressed.

Keywords: CMOS, Silicon nanoplasmonics, Silicon nanophotonics, Onchip integration

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1527

Abstracts

2 A Nanoelectromechanical Tunable Oscillator Base on a High-Q Optical Cavity

Authors: Dim-Lee Kwong, Jifang Tao, Hong Cai, Bin Dong, Aiqun Liu, Yuandong Gu, Jianguo Huang

Abstract:

We developed a miniaturized tunable optomechanical oscillator based on the nanoelectromechanical systems (NEMS) technology, and its frequencies can be electrostatically tuned by as much as 10%. By taking both advantages of optical and electrical spring, the oscillator achieves a high tuning sensitivity without resorting to mechanical tension. In particular, the proposed high-Q optical cavity design greatly enhances the system sensitivity, making it extremely sensitive to the small motional signal.

Keywords: Nanotechnology, oscillator, nanoelectromechanical systems (NEMS), optical force

Procedia PDF Downloads 303
1 Refractometric Optical Sensing by Using Photonics Mach–Zehnder Interferometer

Authors: Dim-Lee Kwong, Jifang Tao, Hong Cai, Gong Zhang, Bin Dong, Aiqun Liu, Yuandong Gu

Abstract:

An on-chip refractive index sensor with high sensitivity and large measurement range is demonstrated in this paper. The sensing structures are based on Mach-Zehnder interferometer configuration, built on the SOI substrate. The wavelength sensitivity of the sensor is estimated to be 3129 nm/RIU. Meanwhile, according to the interference pattern period changes, the measured period sensitivities are 2.9 nm/RIU (TE mode) and 4.21 nm/RIU (TM mode), respectively. As such, the wavelength shift and the period shift can be used for fine index change detection and larger index change detection, respectively. Therefore, the sensor design provides an approach for large index change measurement with high sensitivity.

Keywords: Nanotechnology, Sensors, Mach-Zehnder interferometer, refractive index sensing

Procedia PDF Downloads 283