We experimentally demonstrated a fast optimization algorithm based on the method of gradient descent for achieving optimum spectral response of high-order silicon microring optical filters. The filter optimization was performed on a 4th-order serially-coupled silicon microring filter by thermo-optically tuning the microring resonances using Ti/W heaters. Three different optimization objective functions were used to obtain the optimum filter shape, namely, the single-wavelength method, the dual-wavelength method, and the total transmitted power method. The efficacy of each optimization method was evaluated and compared based on the number of required iterations, the ideality of optimized response, and the wavelength tuning accuracy.
Several silicon-based plasmonic waveguides are proposed for long propagation and ultrafast all-optical modulation
and switching applications. Above-bandgap femtosecond pump pulses are used to generate free carriers in ion-implanted
silicon, resulting in ultrafast nonlinear phase and amplitude modulation. It is demonstrated that by
carefully designing a 5-layer device from silver, ion-implanted silicon and air, it is possible to achieve long
propagation distances (~100μm), or switching times of 5ps and an on-off contrast of 35dB.
We report recent progress in the design and fabrication of coupled optical micro-resonators and their applications in
realizing compact OEIC devices for optical spectral engineering. By leveraging synthesis techniques for analog and
digital electrical circuits, advanced coupled-microring device architectures can be realized with the complexity and
functionality approaching that of state-of-the-art microwave filters. In addition, the traveling wave nature of microring
resonators can be exploited to realize novel devices not possible with standing wave resonators. Applications of coupledmicro-
resonator devices in realizing complex optical transfer functions for amplitude, phase and group delay engineering
will be presented. Progress in the practical implementation of these devices in the Silicon-on-Insulator OEIC platform
will be highlighted along with the challenges and potential for constructing very high order optical filters using coupledmicroring
A theoretical framework is presented for analyzing and synthesizing coupled microring devices of the most general coupling topology. The approach is based on the modeling of an arbitrary system of coupled microresonators by an equivalent electrical network of coupled LC oscillators. The equivalent circuit model enables well-established microwave filter techniques to be leveraged for the design and synthesis of optical filters, allowing complex coupledmicroring architectures to be explored for advanced applications in high-order filtering, dispersion engineering and other spectral shaping functions.