December 15, 2005, Tokyo, Japan--Mitsubishi Electric president and CEO Tamotsu Nomakuchi announced today plans for initial shipment of its ML7xx34 series laser diode on January 10, 2006. The device has an operating temperature range from -40 degrees C to +95 degrees C, and is intended for use in 2.5 Gbps transmission at a wavelength of 1.3 microns.
As Asymmetric Digial Subscriber Line (ADSL), Fiber To The Home (FTTH), and other high-speed, high-capacity communications services spread to the home consumer market, carriers have been rushing to upgrade their fiber optic communications network in the 20 km or so transmission distance area that connects subscribers with trunk lines, Nomakuchi said. Carriers have been looking for small, energy-efficient optical communications devices with high-density mounting for use in these areas, and have been calling for a laser diode capable of high-speed transmission at high temperatures without the need for a temperature controller.
Previous 1.3-micron DFB laser diodes for 2.5 Gbps transmission were limited to an operation temperature range of -20 degrees C to +85 degrees C because of an inverse relationship of high speed response at low and high temperatures with optical output, he said. We have improved the optical conversion efficiency of this laser diode by optimizing the active layer structure, and can now achieve high speed response and optical output at temperatures ranging from -40 degrees C to +95 degree C without temperature control. By optimizing device structure, we have also made a 40% improvement in slope efficiency to 0.36 W/A compared to our previous model, and have improved energy efficiency in the optical receiver.