Projects

On-chip nonclassical light sources
Armand, Konstantinos, Tomas, Kevin
Quantum information processing and cavity QED with quantum dots in photonic crystal nanocavities
Armand, Konstantinos, Tomas, Kevin
Silicon Carbide photonics
Tom, Kai, Marina
Electrically injected nanocavity lasers and modulators
Jan
Silicon Germanium photonics
Jan
Nonlinear optics in nanophotonic structures
Sonia, Marina, Linda
Nanophotonic devices for biomedical applications
Alex, Jan
Objective-First Design for Nanophotonics
Alex
Videos of our research

Silicon germanium photonics

A germanium LED


A germanium microdisk side coupled to a fiber taper

The Idea:

Reasons:

Challenges

Germanium is an indirect band gap semiconductor and as such it is ordinarily a poor optical emitter. However the indirect band edge is only 0.13 eV below the direct band edge and by heavily doping the material or by applying a sufficient strain, the material can become quasi-direct band gap. Finding suitable fabrication methods to heavily dope or inject carriers into germanium are difficult and we are exploring this area in order to overcome this hurdle.

Achievements

Techniques:

Images of tapered fiber aligned to single photonic crystal cavity

While many experiments on nanocavities such as photonic crystal cavities can be performed using conventional free space optics, there are certain limitations on the efficiencies of injecting and extracting optical signals. Transferring light in and out of nanocavities can also be readily accomplished by drawing a conventional optical fiber down to ~1 um in diameter and positioning the waveguide near the cavities. This process has many advantages since the tapered fiber provides an additional channel to inject and extract multiple signals. Efficiencies have been shown to be high, and rapid characterization of numerous devices can be done very quickly [1-3].

  1. Hwang, In-Kag et al., APL 87, 131107 (2005).
  2. Smith, C., Physica B 394, 289 (2007).
  3. Srinivasan, K., IEEE J. Sel. Areas Comm. 23, 1321 (2005).
last modified on Thursday November 10, 2011