Quantum dot lasers

A quantum dot laser is a semiconductor laser utilizing quantum dot crystals as an active layer to produce optical gain. Light outputs of these quantum dot lasers are virtually temperature-independent between -40 and 100℃. This temperature tolerance allows the elimination of expensive coolers and control circuits, allowing customers to realize compact and reliable high density packaging in optical transceivers.
Furthermore, quantum dot technology is not limited to use in optical telecommunications. It can be expanded to the field of consumer electronics applications such as optical interconnections and industrial applications.

Quantum Dot Laser vs. Bulk Laser (temperature sensitivity)
Here we compare photon-emission mechanisms in bulk and quantum dot semiconductors. In bulky materials, carriers (electrons and holes) recombine and emit photons effectively at low temperature. However, as the temperature rises, carriers move quicker in the material leading to a reduced likelihood of recombination and a decrease in photon emission rates.

In the case of quantum dots, the electrons, the holes and the ultra small semiconductor materials are confined in a tiny structure, so the carriers can hardly move, even at elevated temperatures. Thus, photon emissions proceed with high efficiency, like at low temperatures. As a result, the temperature dependency of the light-current characteristics of a quantum-dot laser becomes minimal.

This movie requires Flash Player 9


High temperature operation of quantum dot lasers

active layers drastically reduce temperature sensitivity of light output characteristics of 1300nm communication wavelength lasers.