Low-loss singlemode amorphous silicon waveguides

Picosecond all-optical switching in hydrogenated amorphous silicon microring resonators

“…In addition to bound-electronic nonlinear effects due to χ (3) , other physical processes based on real (rather than virtual) excitations can impart an index change ∆n. Optical switching experiments in c-Si are dominated by effects due to free carriers [16].…”

“…A-Si:H has become more widely used as a photonic material in the past several years as investigators have found that its nonlinear optical properties in the telecom band are superior to those of c-Si. A-Si:H single-and multimode waveguides were fabricated in 2005 [3], and reports of resonators with Q's exceeding 10 4 date from 2009, fabricated using both traditional and damascene processes [4,5]. Investigations of nonlinear properties have focused either on characterization of material nonlinearity through self-phase modulation experiments [6], pump-probe experiments to characterize waveguides [7,8], or fourwave mixing for wavelength conversion [9,10].…”

Laser Annealing of Low Temperature Deposited Silicon Waveguides

“…However, c-Si photonic devices are relatively difficult to integrate with the electronic layers due to fabrication constraints. Thus more recently there has been increased interest in deposited silicon materials, including hydrogenated amorphous silicon (a-Si:H) [1], silicon nitride (SiN) and polycrystalline silicon (poly-Si) [2]. Although waveguides produced from a-Si:H and SiN can exhibit very low losses, in some cases lower than c-Si, their electronic properties are inferior.…”

Label-free photonic biosensors fabricated with low-loss hydrogenated amorphous silicon resonators

“…1,2 Instead of using crystalline silicon-on-insulator (SOI) wafers as photonic substrates, low-loss hydrogenated amorphous silicon (a-Si:H) that is deposited by plasma-enhanced chemical vapor deposition (PECVD) is alternatively employed in this work because it provides a high refractive index (n ≈ 3.5) and low-loss material for near-infrared photonics, both comparable to crystalline silicon. 3 However, a-Si:H offers a more flexible fabrication process since it can be deposited at relatively low temperatures (≤300°C) and therefore allows using glass or plastic materials as substrates. 4,5 This facilitates a low-cost fabrication and offers more processing options, e.g., for the combination with microfluidic channels using split-and-recombine micromixers or for the arrangement of the sensing resonators that can be principally fabricated in a vertically stacked configuration.…”