Ultralow Power Wavelength Conversion and Regeneration Technologies

More than 90% of power consumption in conventional routers takes place in the linecards where O/E/O conversion and electronic signal processing occur.  Low power and all-optical regeneration is a key to chip-scale optical routers.  Typical regenerating wavelength converters employ cross-gain (XGM) or cross-phase modulation (XPM) in semiconductor optical amplifiers. Due to unfavorable gain recovery time and carrier effects, it is difficult to achieve low-power wavelength conversion without signal distortion in the SOA based devices.  SOAs need to receive high-injection current to speed up the carrier dynamics.  The commercial 10 Gb/s XPM wavelength converters consume more than 500 mA current each (>500 mW power consumption), and require above 1000 mW power consumption for 40 Gb/s operation.  The proposed low-power regenerating wavelength converter utilizes completely different physical mechanisms for wavelength conversion, and this allows extremely low power, very high speed operation.  Fig. II.7 (a) illustrates the device.  The proposed method avoids the high operating current requirements of the SOA based devices and provides higher quality signal regeneration.  Fig. II.7 (b) is an array of wavelength converters fabricated in our group.