Compact and low power consumption tunable photonic crystal nanobeam cavity

A proof-of-concept for a new and entirely CMOS compatible tunable nanobeam cavity is demonstrated in this paper. Preliminary results show that a compact nanobeam cavity (~20 μm^2) with high Q-factor (~50,000) and integrated with a micro-heater atop, is able of tuning the resonant wavelength up to 15 nm with low power consumption (0.35nm/mW), and of attaining high modulation depth with only ~100 μW. Additionally, a tunable bi-stable behavior is reported

Experimental demonstration of a unidirectional reflectionless parity-time metamaterial at optical frequencies

Invisibility by metamaterials is of great interest, where optical properties are manipulated in the real permittivity– permeability plane. However, the most effective approach to achieving invisibility in various military applications is to absorb the electromagnetic waves emitted from radar to minimize the corresponding reflection and scattering, such that no signal gets bounced back. Here, we show the experimental realization of chip-scale unidirectional reflectionless optical metamaterials near the spontaneous parity-time symmetry phase transition point where reflection from one side is significantly suppressed. This is enabled by engineering the corresponding optical properties of the designed paritytime metamaterial in the complex dielectric permittivity plane. Numerical simulations and experimental verification consistently exhibit asymmetric reflection with high contrast ratios around a wavelength of of 1,550 nm. The demonstrated unidirectional phenomenon at the corresponding parity-time exceptional point on-a-chip confirms the feasibility of creating complicated on-chip parity-time metamaterials and optical devices based on their properties

Reconfigurable silicon thermo-optical ring resonator switch based on Vernier effect control

A proof-of-concept for a new and entirely CMOS compatible thermo-optic reconfigurable switch based on a coupled ring resonator structure is experimentally demonstrated in this paper. Preliminary results show that a single optical device is capable of combining several functionalities, such as tunable filtering, non-blocking switching and reconfigurability, in a single device with compact footprint (~50μm x 30μm)

Experimental demonstration of a reconfigurable silicon thermo-optical device based on spectral tuning of ring resonators for optical signal processing

We have experimentally demonstrated a reconfigurable silicon thermo-optical device able to tailor its intrinsic spectral optical response by means of the thermo-optical control of individual and uncoupled resonant modes of micro-ring resonators. Preliminarily results show that the device’s optical response can be tailored to build up distinct and reconfigurable logic levels for optical signal processing, as well as control of overall figures of merit, such as free-spectral-range, extinction ratio and 3dB bandwidth. In addition, the micro-heaters on top of the ring resonators are able to tune the resonant wavelength with efficiency of 0.25 nm/mW within a range of up to 10 nm, as well as able to switch the resonant wavelength within fall and rise time of 15 μs

Thermally Controllable Silicon Photonic Crystal Nanobeam Cavity without Surface Cladding for Sensing Applications

Photonic crystal nanobeam cavities with high-quality factors are very sensitive to the dielectric properties of their surroundings. Combining this high sensitivity with a specially designed heater, we experimentally demonstrate a very sensitive optical sensor, capable of simultaneously providing heat and interrogating the refractive index of its surroundings. The structure presents experimental sensitivity of 98 nm/RIU and signal-to-noise ratio of 3.88 × 10^(–4) RIU and provides approximately 100 °C of temperature variation in the sensing area, with a temperature switching time of a few microseconds

Athermal Silicon Slot Waveguide With an Ormocomp Polymer Overlayer

We have demonstrated a proof-of-concept for an athermal silicon slot waveguide using Ormocomp as a top cladding. Preliminarily theoretical and experimental results show that the slot waveguide geometry can completely cancel out its thermo-optical coefficient, by tailoring the optical mode overlap with silicon, silicon dioxide, and Ormocomp