Magnolia touts high-speed VCSEL links
Magnolia Optical Technologies of Woburn, MA, has developed what it believes to be the first 120 Gb/s fiber-optic transmitter and receiver modules.
The modules feature 12 parallel channels, each operating at 10 Gb/s. The transmitter module uses 850 nm vertical cavity surface-emitting laser (VCSEL) sources while the receiver element features a PIN diode array.
With funding from the US Army s Tank and Automotive Command division, it s no surprise that the initial applications of the technology will be in combat systems.
As well as providing a high-speed local area network (LAN) for ground vehicles, the 120 Gb/s modules could be used in next-generation warplanes such as the Joint Strike Fighter to connect missile systems with processing architecture.
Magnolia president and co-founder Ashok Sood told Compoundsemiconductor.net that the links could have a number of commercial applications too, although these are not expected to materialize for some years while the modules are made sufficiently rugged and their cost drops considerably.
One of the key technological difficulties that the Magnolia team has overcome is that of parasitic capacitance. Sood says that when increasing the speed of each parallel channel from 2 Gb/s to 10 Gb/s, this becomes a critical issue, suppressing the frequency response of the overall module.
The packaging scheme used to house and align the various components becomes critical when it comes to maintaining signal integrity at these high speeds, he explained.
Sood added that although the high-speed module s applications are exclusively military right now, some commercial uses could arise. For instance, the transfer of medical images that carry a very high data burden (such as MRI scans) could be one such application. "These images are stored in a network, and [our] modules would be very useful for delivering them from a central hospital computer around the local network at a very high speed."
At the moment, the use of 850 nm VCSELs limits the range of such links to LAN use. Magnolia s next goal is to incorporate 1310 nm VCSELs into its module design, which ought to extend the link range to several kilometers.
Set up in May 2000, Magnolia had initially planned to manufacture VCSEL sources in-house, but scrapped these plans as expected venture funding dried up following the telecoms bust.
Sood and colleagues decided to operate the company as a fabless enterprise and source VCSEL chips from vendors including Honeywell (now Finisar) and Germany-based Ulm Photonics.
