By MIKE DOWNING
TECHNOLOGYThe suddenly expanding array of options for long-wavelength vertical-cavity surface-emitting lasers (VCSELs) has grown even larger. Nova Crystals (San Jose, CA) recently demonstrated its version of a practical, electrically pumped 1,300-nm VCSEL emitting what the company claims is a record 1-mW of power. The device delivers the operating characteristics necessary to enable telecommunications and data-communications transmission and is reliable enough for commercial use, touts the laser's developers.
Nova Crystals CEO Felix Ejeckam and chief operating officer Ty Mitchell believe that the development of longer-wavelength VCSEL technology will extend the reach of the traditional LANs and may also bring about the demise of more expensive Fabry-Perot lasers.
Ejeckam said Nova Crystals is addressing two trends with its VCSEL technology, one each on the data-communications and telecommunications sides. "On the datacom side, there have been several recent developments in generating high-bandwidth solutions for short-distance applications," he says. "But that bandwidth hasn't gone past the distance of 400 m. We are trying to extend the reach of devices beyond that limit. We believe the traditional LAN needs to grow beyond the 400-m circle. It needs to grow to tens of kilometers. Long-wavelength VCSELs enable datacom bandwidth to leave the confines of the building and move closer to the network's core."
On the telecom side, Ejeckam argues that, despite a number of advancements, high-bandwidth solutions have not moved much closer to the consumer. "Engineers have developed expensive, high-bandwidth solutions for the core of the network, but those advancements haven't reached the consumer," he says. "The low cost of VCSELs will enable advancements in telecom technology to move beyond the core and closer to the curb...and eventually closer to the home."
According to Mitchell, the short-term implications of longer-wavelength VCSELs include the rapid merging of LANs and WANs. "You'll see more LANs extending beyond the building," he surmises. "These VCSELs will also move into MANs and into WDM applications. They will be able to take the cost-effectiveness in the LAN and extend it over 20 to 40 km."
Mitchell sees the long-term impact involving a gradual migration toward VCSELs throughout the component space. "But it's going to take some time, especially in the high end, where you have DFB [distributed-feedback] lasers," he says. "At the same time, VCSELs are going to continue to improve. They already offer lower processing costs and lower manufacturing costs. So VCSELs are going to represent a strong alternative throughout the component space."
Will VCSEL technology eventually replace the Fabry-Perot laser? Ejeckam says yes. "It's mostly a question of cost," he explains. "It's not only cheaper to make a VCSEL chip, it's also cheaper to make the module. All the while, you're getting better performance. VCSELs provide a more narrow, circular beam. Therefore, the angle of divergence is much less in a VCSEL than in an edge-emitting laser. It's much easier to align the fiber with the chip. There is also the benefit of wafer-scale manufacturing and testing which you don't get with edge-emitting products. Those are key packaging benefits of VCSELs."
Ejeckam and Mitchell both acknowledged the spate of announcements in the long-wavelength VCSEL space. "There have been earlier announcements of optically pumped, long-wavelength VCSELs," concedes Mitchell. "But more recent announcements, including ours, have involved electrically pumped VCSELs."
What's the difference? According to Mitchell, optical pumping is a more complex approach. "An optically pumped VCSEL typically requires an electric current which pumps a laser at, say, 850 nm or 980 nm. Then, that laser pumps the 1,300-nm or 1,500-nm VCSEL. We eliminate the additional laser."
Nova Crystals has not yet shared its product with analysts. Instead, the company has been working to address customer needs while ramping up production capacity and capabilities. "We plan to meet with the analysts in October," reports Ejeckam.
Mitchell adds that the Nova Crystal VCSEL product would be in the sampling and testing phase in this month, with commercial product available early next year. Nova Crystals is a privately held company backed by strategic and venture capital. The company was founded in September 1998 and employs 21 people.
Nova Crystals follows the lead of Cielo Communications (Broomfield, CO), which has been working on electrically pumped long-wavelength VCSELs (with 0.06-mW power) in cooperation with Sandia National Laboratories of Albuquerque, NM (see Lightwave, August 2000, page 1). In addition, Bandwidth9 (Fremont, CA) has announced a comparable breakthrough in VCSEL development in the 1,600-nm regime. Principals at Bandwidth9 were unavailable for comment as this issue went to press.