Photonics Research, 2014, 2 (5): 05000102, Published Online: Jan. 23, 2019
Mid-infrared 2 × 2 electro-optical switching by silicon and germanium three-waveguide and four-waveguide directional couplers using free-carrier injection Download: 883次
Optical switching devices Electro-optical materials Electro-optical devices Photonic integrated circuits
Abstract
New designs are proposed for electro-optical switching in the 1.3–12 μm wavelength range. Directional couplers are analyzed using a two-dimensional effective-index approximation. It is shown that three or four side-coupled Si or Ge channel waveguides can provide complete crossbar broad-spectrum switching when the central waveguides are injected with electrons and holes to modify the waveguides’ core index by an amount . The four-waveguide device is found to have a required active length that is 50% shorter than for the three-waveguide switch. A rule of for 3w and for 4w is deduced to promise insertion loss and crosstalk at the bar state. At an injection of , the predicted decreased from to as increased from 1.32 to 12 μm. Because of Ge’s large , the Ge bar loss is high in 4w but is acceptable in 3w.
Richard Soref. Mid-infrared 2 × 2 electro-optical switching by silicon and germanium three-waveguide and four-waveguide directional couplers using free-carrier injection[J]. Photonics Research, 2014, 2(5): 05000102.