Amir H. Hosseinnia

Compact, 15 Gb/s electro-optic modulator through carrier accumulation in a hybrid Si/SiO(2)/Si microdisk.

High-speed electro-optic modulators are among the key elements in any optical interconnect system. In this work we design and demonstrate an electro-optic modulator based on carrier accumulation on a multilayer integrated photonic platform comprising a stack of high quality Si, SiO(2), and Si layers. The device consists of a 3-μm radius microdisk with an embedded capacitor. Characterization results reveal an operation bandwidth of exceeding 10 GHz. The device is capable of transmitting 15 Gb/s with the on/off keying format in a single polarization. The proposed structure can be self-trimmed by up to 1 nm in wavelength by applying a dc bias voltage without any power consumption. This feature eliminates the need for power-hungry thermal-based compensation methods to address the resonance wavelength mismatch due to fabrication imperfections.

Double-Layer Crystalline Silicon on Insulator Material Platform for Integrated Photonic Applications

We report a high optical-quality double-layer silicon (Si) material platform with a thin interface oxide using a low-temperature wafer bonding technique. To assess the quality of the platform, resonators with different radii are fabricated, and their quality factors (Q) are measured. Qs of 25 k and 350 k are demonstrated in 2-μm- and 20-μm-radius microring resonators, respectively. The former is the most compact high-Q resonator demonstrated in any type of double-layer Si platform, and the latter is the highest Q demonstrated in a double-layer Si platform to date. This material platform enables a new set of integrated optical devices for a wide range of applications, including high-speed modulators, tunable filters, and low-power switches.

High-quality silicon on silicon nitride integrated optical platform with an octave-spanning adiabatic interlayer coupler

Hybrid nanophotonic platforms based on three-dimensional integration of different photonic materials are emerging as promising ecosystems for the optoelectronic device fabrication. In order to benefit from key features of both silicon (Si) and silicon nitride (SiN) on a single chip, we have developed a wafer-scale hybrid photonic platform based on the integration of a thin crystalline Si layer on top of a thin SiN layer with an ultra-thin oxide buffer layer. A complete optical path in the hybrid platform is demonstrated by coupling light back and forth between nanophotonic devices in Si and SiN layers. Using an adiabatic tapered coupling method, a record-low interlayer coupling-loss of 0.02 dB is achieved at 1550 nm telecommunication wavelength window. We also demonstrate high-Q resonators on the hybrid material platform with intrinsic Qs as high as 3 × 10(6) for a 60 μm-radius microring resonator, which is (to the best of our knowledge) the highest Q observed for a micro-resonator on a hybrid Si/SiN platform.

Field-programmable optical devices based on resonance elimination

Optical switches are among the essential building blocks in optical networks due to their unique role in routing data. In this Letter, for the first time to our knowledge, we have exploited a high-quality factor (Q) optical microresonator combined with the well-known irreversible dielectric breakdown phenomenon to introduce a simple field-programmable on/off optical switch. This simple unit can be thought of as a building block for more complex optical systems with different functionalities. By using this simple unit we have demonstrated an optical field-programmable 2×2 switch. After the device is programmed by the user, no external electrical signal is needed to maintain the state of the device. The same approach can readily be adopted to design a field-programmable arbitrary N×N optical switch.

Multilayer Platform for Low-Power/Passive Configurable Photonic Device

We demonstrate the possibility of forming ultra-compact, field-configurable, and low-power resonance-based passive integrated photonic structures based on charge accumulation in a high-quality multilayer material platform comprising Si/SiO2/Si layers prepared through direct bonding of SOI wafers.

Determination of complex modes in photonic crystal waveguides using the phase variation in characteristic coefficients

An efficient frequency-domain method, the phase variation monitoring (PVM) method, is proposed to determine the electromagnetic eigenmodes in two-dimensional photonic crystal waveguides. The proposed method is based on monitoring the reflection and transmission coefficients of incident plane waves. It is successfully applied to an illustrative line-defect photonic crystal waveguide and proved to be capable of calculating the in-plane leakage through the finite-size photonic crystal surrounding the line-defect. Calculation of the leakage loss is not only important for proper understanding of wave propagation within the defect but also for its significant role in applications of photonic structures.

Large enhancement of second harmonic emission using lattice plasmon polaritons

We demonstrate a bilayer nanostructure, supporting lattice plasmon polaritons and vertically confined localized plasmonic modes. Fano-type resonance increases the net absorption cross-section of the nanostructure, resulting in a significant enhancement in the second harmonic intensity.