February 27, 2004 Oxfordshire, UK -- Bookham Technology plc recently unveiled an integrated 10-Gbit/sec InP MZ (Mach-Zehnder) modulator packaged with a high power CW laser. Officially called the LMC10NEH, the Indium-Phosphide-based device allows 10-Gbit/sec transmissions to be sent over 100 km without dispersion compensation. Although this functionality has been available in a larger device for several years, Bookham claims it has shrunk the unit size by 60%; the device measures just 30- by 12.7- by 8.1-mm.
The LMC10NEH has just completed full Telcordia Qualification and has been shipping in volume. The laser modulator is part of a large family of products called Compact MZ. Bookham displayed the new device as part of its Virtual Live Demo on the company's stand at OFC.
"The development is taking what we already offer but making it much smaller," explains Adam Price, Bookham's product line manager for the InP MZ portfolio. "In this industry, people care about the size of the components. Density really does add value."
According to Price, the nearest competition to the Compact MZ in terms of size would be an electro-absorption (EA) modulator, but such a device offers significantly lower performance in terms of reach, optical power, and extinction ratio. The nearest competition in terms of performance would be a LiNbO3 modulator, which can transmit over long distances but, he says, "those solutions are typically much larger especially when coupled to a CW laser."
A typical directly modulated 14-pin laser has seven pins on each side, but the Compact MZ has its pins located only on one side to increase potential density of devices on a board and facilitate attachment to a heatsink. "We call this design a half-wing butterfly," says Price.
Bookham has reduced the length of the optical train, thanks in part to a novel co-packaging technique that results in a package that is no bigger than a typical directly modulated laser.
Key target applications for the Compact MZ are within high performance regional metro systems. Price confirms that a number of Tier-1 system manufacturers are already buying volume quantities of the LMC10NEH. "The regional metro marketplace had for some time been based on 2.5-Gbit/sec traffic, but what network manufacturers are now doing is increasing capacity by overlaying 10-Gbit/sec transmissions on these links that are typically up to 120-km long. With the trends we are seeing in the market regarding shifts towards pluggable smaller footprint optics such as XFP, the company believes that InP MZ development could be a key enabling technology in the future to smaller high performance optics," he adds.