Semiconductor optical amplifiers

Contacts:

Kresten Yvind, DTU Fotonik, Nanophotonic devices, 4525-6366 (kryv@fotonik.dtu.dk)

Upper: Probing station for efficient optical and electrical access to the device under test. Lower: Example of device (here mounted and bonded).

If one is to choose a single most important functionality in optical circuits it would be the amplifier. It can be used to compensate the loss in complex circuits, and is the gain element in semiconductor lasers. The semiconductor optical amplifier is very attractive since it is very compact, lends itself to monolithic integration with other components and allows direct pumping by an electrical current. It does however require accurate engineering to ensure low noise and low polarization dependence.

At DTU Fotonik we make waveguides and amplifiers as part of the research on photonic integrated circuits. These should be characterized and the result related to the structure and/or processing of the devices. The active medium (where the electron-photon interaction takes place) can be (strained) bulk, quantum wells or quantum dots. Characterization of passive waveguide components or other test structures may also be done to evaluate the cleanroom processing.

The project:

Processed semiconductor material from the Danchip cleanroom should be mounted and antireflection-coated to make travelling wave amplifiers. These should be characterized on the optoelectronic probing station. Measurements include gain, noise and saturation power for a constant light input (CW) as function of wavelength, polarization and current applied to the device. Labview should be used to automate the measurements and the results should be analyzed e.g. though a simple model.

Many variants of this project may also be done going more in detail with some of the many issues.