Abstract

So far, the capacity of the communication systems has increased by wavelength division multiplexing (WDM) and systems with 160 wavelengths have been installed. However, there arise various difficulties for further increase of the wavelength number, for example the management of wavelengths, footprint of the equipments, and power consumption. An alternative is to increase the channel bit-rate and to realize large capacity with smaller number of wavelengths. For systems above 100Gb/s of single channel transmission speed, optical time domain multiplexing technology (OTDM) is required because the limit of the speed of electronic devices is assumed to be around 100Gb/s. For OTDM systems we need ultra-fast all-optical switches for functions such as multiplexing, de-multiplexing, pulse reshaping and retiming. These switches are required to show very fast response together with low switching energy. As a candidate for such switches we are developing intersubband transition all-optical switch using the absorption saturation of InGaAs/AlAs/AlAsSb coupled double-quantum (c-DQW). Here, we present our efforts to reduce the switching energy and the the-state-of-the-art performances.

© 2004 Optical Society of America