Ke-Yao Wang

Ultralow power continuous-wave frequency conversion in hydrogenated amorphous silicon waveguides.

We demonstrate nonlinear frequency conversion in hydrogenated amorphous silicon (a-Si:H) with conversion efficiency of -13dB at telecommunication data rates. Conversion bandwidths of 150nm are measured in CW regime at telecommunication wavelengths.

Ultralow-power all-optical processing of high-speed data signals in deposited silicon waveguides

Utilizing a 6-mm-long hydrogenated amorphous silicon nanowaveguide, we demonstrate error-free (BER < 10(-9)) 160-to-10 Gb/s OTDM demultiplexing using ultralow switching peak powers of 50 mW. This material is deposited at low temperatures enabling a path toward multilayer integration and therefore massive scaling of the number of devices in a single photonic chip.

Wavelength-agile near-IR optical parametric oscillator using a deposited silicon waveguide.

Using a deposited hydrogenated amorphous silicon (a-Si:H) waveguide, we demonstrate ultra-broad bandwidth (60 THz) parametric amplification via four-wave mixing (FWM), and subsequently achieve the first silicon optical parametric oscillator (OPO) at near-IR wavelengths. Utilization of the time-dispersion-tuned technique provides an optical source with active wavelength tuning over 42 THz with a fixed pump wave.

Non-instantaneous optical nonlinearity of an a-Si:H nanowire waveguide.

We use pump-probe spectroscopy and continuous wave cross-phase and cross-amplitude modulation measurements to study the optical nonlinearity of a hydrogenated amorphous silicon (a-Si:H) nanowire waveguide, and we compare the results to those of a crystalline silicon waveguide of similar dimensions. The a-Si:H nanowire shows essentially zero instantaneous two-photon absorption, but it displays a strong, long-lived non-instantaneous nonlinearity that is both absorptive and refractive. Power scaling measurements show that this non-instantaneous nonlinearity in a-Si:H scales as a third-order nonlinearity, and the refractive component possesses the opposite sign to that expected for free-carrier dispersion.

GHz Near-IR Optical Parametric Amplifier using a Hydrogenated Amorphous Silicon Waveguide

We demonstrate for the first time optical parametric amplification (OPA) operating at GHz rate in near-IR using hydrogenated amorphous silicon waveguide. The strong gain at this repetition rate shows its potential for telecommunication applications and a GHz-rate optical parametric oscillator.

GHz-rate optical parametric amplifier in hydrogenated amorphous silicon

We demonstrate optical parametric amplification operating at GHz-rates at telecommunications wavelengths using a hydrogenated amorphous silicon waveguide through the nonlinear optical process of four-wave mixing. We investigate how the parametric amplification scales with repetition rate. The ability to achieve amplification at GHz-repetition rates shows hydrogenated amorphous silicons potential for telecommunication applications and a GHz-rate optical parametric oscillator.

Highly sensitive ultrafast pulse characterization using hydrogenated amorphous silicon waveguides

We experimentally demonstrate frequency resolved optical gating (FROG) via four-wave mixing (FWM) in ultrahigh nonlinearity hydrogenated amorphous silicon waveguides. We demonstrate FROG characterization using a FWM architecture that mimics second harmonic generation (SHG) FROG for pulsewidths as low as 360 fs. Additionally, we demonstrate for the first time a FWM architecture analogous to third harmonic generation (THG) FROG and validate its ability to overcome the direction of time ambiguity of the SHG-like architecture. Both architectures allow for sensitivities suitable for future telecommunications signals.

Coherent mid-IR supercontinuum generation in a hydrogenated amorphous silicon waveguide

We generate a 790-nm wide Mid-IR supercontinuum, spanning from 1.63 μm to 2.42 μm, in a hydrogenated amorphous silicon waveguide. The pump source is a 160-fs Thulium doped fiber laser centered at 1910 nm.

Highly-sensitive ultrafast pulse characterization utilizing four-wave mixing in an amorphous silicon nanowaveguide

We demonstrate frequency-resolved optical gating using four-wave mixing in a hydrogenated amorphous silicon nanowaveguide. The ultrahigh nonlinearity and the wide conversion bandwidth of this device allow characterization of sub-ps pulses with high sensitivity.

Ultralow-power 160-to-10Gb/s optical demultiplexing using four-wave mixing in deposited silicon waveguides

Utilizing a 6-mm-long hydrogenated amorphous silicon nanowaveguide, we demonstrate error-free (BER <; 10-9) 160-to-10 Gb/s OTDM demultiplexing using ultralow switching peak powers of 50 mW. This material is deposited at low temperatures enabling a path toward multilayer integration and therefore massive scaling of the number of devices in a single photonic chip.