InP stretches Japanese backbone to 40 Gbps
Japanese systems company Yokogawa Electric s optical transmission collaboration with its compatriot Fujitsu has developed InP HBTs that play a pivotal role in its high-speed networks, replacing existing CMOS technology.
A Fujitsu spokesman told compoundsemiconductor.net the technology has already been introduced to a Japanese backbone network, with the companies seeking opportunities in other markets.
InP HBTs were used in a number of the system's components, including the optical signal modulator driver, optical/electrical converters and clock and data recovery devices.
The spokesman for the giant Japanese IT and communications company said, “The InP device for 40Gbps optical transmission networks uses a brand new compound semiconductor, developed under the Fujitsu and Yokogawa collaboration agreement, to realize 40Gbps differential quadrature phase shift keying (DQPSK) technology.”
Fujitsu and Yokogawa say that the new network system features the first practical 40 Gbps optical transmission technologies including DQPSK signal modulation.
Increasing the transmission speed of an optical network leads to increased distortion of transmitted signals by polarized mode dispersion (PMD), which restricts the operating range of the network.
The system s InP optical/electrical converters help boost transmission reach by operating stably despite PMD distortion.
Otherwise, the InP HBTs drive the device which performs DQPSK modulation, which is considered to be tolerant of signal distortion caused by PMD.
By applying these advances, Fujitsu and Yokogawa claim to have improved upon range limits of 100 km previously faced by high-speed optical networks by “approximately 8 times”.
“The system jointly developed with Yokogawa can dramatically improve transmission distance in comparison to existing technology,” stated Fujitsu.
According to the companies, CMOS devices used for 10Gbps systems have been surpassed by their InP HBT devices, which offer “outstanding high-speed performance and high drive capability with low IC power consumption.”
The two companies have been collaborating since March 2006, working on the development of ultra-high speed optical transmission systems.