Ahmad Rifqi Md Zain

Ultra high quality factor one dimensional photonic crystal/photonic wire micro-cavities in silicon-on-insulator (SOI)

We present experimental results on photonic crystal/photonic wire micro-cavity structures that demonstrate further enhancement of the quality-factor (Q-factor)--up to approximately 149,000--in the fibre telecommunications wavelength range. The Q-values and the useful transmission levels achieved are due, in particular, to the combination of both tapering within and outside the micro-cavity, with carefully designed hole diameters and non-periodic hole placement within the tapered section. Our 2D Finite Difference Time Domain (FDTD) simulation approach shows good agreement with the experimental results.

Tapered Photonic Crystal Microcavities Embedded in Photonic Wire Waveguides With Large Resonance Quality-Factor and High Transmission

We present the design, fabrication, and characterization of a microcavity that exhibits simultaneously high transmission and large resonance quality-factor (Q-factor). This microcavity is formed by a single-row photonic crystal (PhC) embedded in a 500-nm-wide photonic wire waveguide - and is based on silicon-on-insulator. A normalized transmission of 85%, together with a Q-factor of 18 500, have been achieved experimentally through the use of carefully designed tapering on both sides of each of the hole-type PhC mirrors that form the microcavity. We have also demonstrated reasonably accurate control of the cavity resonance frequency. Simulation of the device using a three-dimensional finite-difference time-domain approach shows good agreement with the experimental results.

All-optical switching in silicon-on-insulator photonic wire nano–cavities

All-optical switching with a very low power is demonstrated on photonic crystal wire nano-cavities on silicon-on-insulator with large quality factors and high transmission in the telecom range.

Photonic crystal and photonic wire nano-photonics based on silicon-on-insulator

Silicon-on-insulator (SOI) is a strong candidate for application in future planar waveguide integration technology, whether or not luminescence is extracted from the silicon. We review recent research on photonic devices based on silicon-on-insulator. These devices exploit either photonic crystal or photonic wire concepts—or combinations of both. Aspects of the technologies used that are particularly critical for successful implementation of SOI-based photonics are addressed.

Photonic crystal and photonic wire device structures

Photonic devices that exploit photonic crystal (PhC) principles in a planar environment continue to provide a fertile field of research. 2D PhC based channel waveguides can provide both strong confinement and controlled dispersion behaviour. In conjunction with, for instance, various electro-optic, thermo-optic and other effects, a range of device functionality is accessible in very compact PhC channel-guide devices that offer the potential for high-density integration. Low enough propagation losses are now being obtained with photonic crystal channel-guide structures that their use in real applications has become plausible. Photonic wires (PhWs) can also provide strong confinement and low propagation losses. Bragg-gratings imposed on photonic wires can provide dispersion and frequency selection in device structures that are intrinsically simpler than 2D PhC channel guides--and can compete with them under realistic conditions.

High-transmission 1D photonic crystal/photonic wire multiple cavity structures based on silicon-on-insulator

This paper describes the design, modeling, fabrication and characterization of single-row photonic crystal multiple micro-cavity structures embedded in 500 nm photonic wire waveguides. The strength of coupling between the resonators and the free spectral range (FSR) between the split resonance frequencies of the coupled-cavity combination were controlled via the use of different numbers of periodic hole structures - and through the use of different aperiodic hole taper arrangements between the two cavities in the middle mirror section of the mirrors. Both 2D and 3D finite-difference time-domain (FDTD) computations have been used to simulate the device structures. Comparisons have been made with the results of measurements and show good agreement.

Advancing the performance of one-dimensional photonic crystal/photonic wire micro-cavities in silicon-on-insulator

We present new results that demonstrate advances in the performance achievable in photonic crystal/photonic wire micro-cavities. In one example, a quality-factor value as high as 147,000 has been achieved experimentally at a useful transmission level.

Fine tuning of single row photonic crystal extended cavities embedded in photonic wire waveguides

This paper describes the realization of high quality factor (Q-factor) single row photonic crystal extended cavity structures embedded in 500 nm wide photonic wire waveguides. Cavities spacer lengths of between 2 µm and 9 µm have been inserted between two periodic mirrors with aperiodic tapering of the hole diameter and the spacing between holes. A Q-factor value of approximately 74,000 has been measured for a 5 µm long cavity at a selected resonance frequency. We have also demonstrated experimentally a tuning capability for the resonance frequency by means of small variations of the cavity length. A shift of approximately 10 nm in resonance frequency has been obtained for a 250 nm variation of the cavity length, both in simulation and in measured results. In addition, a free spectral range (FSR) in resonance frequency of between 20 nm and 30 nm has also been demonstrated for a small variation in the mirror hole diameter of approximately 20 nm. Tapering within and outside the cavity has produced a substantial increase in both the Q-factor and the optical transmission at resonance. Both 2D and 3D finite-difference time-domain (FDTD) computations have been used to simulate the device structures. Comparisons between the simulation and measured results show reasonably good agreement.

Photonic crystal cavities embedded in photonic wire waveguides

This paper describes the realization of high quality-factor (Q-factor) and high transmission photonic crystal micro-cavity and extended cavity structures embedded in photonic wire waveguides. Q-factor of as much as 16600 have been achieved in micro-cavities with transmission of more than 80%. We have also fabricated an 8 μm long extended cavity with a measured Q-factor of 5100 with normalised transmission of around 67%. Three-dimensional (3D) Finite Difference Time Domain (FDTD) computation has been used to simulate the devices. Comparison of the simulation and measured result shows reasonably good agreement.

Single Row SOI-Based Photonic Crystal/Photonic Wire Micro-cavities with Medium Q-factor and High Transmission

We present the results of a study of tapered hole structures for realising medium quality-factor (Q-factor), high-transmission photonic crystal/photonic wire micro-cavities. Q-factors of more than 3,000 and transmission of 80% have been simultaneously achieved.