x
Optical/IP Networks

Laser Blazers

Short wavelength means around 850 nanometers. It's no coincidence that this is the wavelength at which silicon detectors are most sensitive.

However, this wavelength is not the optimum for transmitting signals over optical fiber. At 850nm, attenuation is pretty high, so signals can only go up to a kilometer over singlemode fiber, and less than this over multimode.

Still, there are plenty of applications where a long range is not required, such as Fibre Channel, Ethernet, and intrasystem links (among switches, routers and hubs inside the central office).

VCSEL arrays, comprising multiple lasers in the same package, make it possible to transmit high data rates cheaply. These days, pretty much every manufacturer supplying single VCSELs at 850nm also offers VCSEL arrays at the same wavelength.

Differentiators

Technologically, one vendor's 850nm VCSEL is pretty much the same as any other, says Mike Hartmann, director of marketing at E2O Communications Inc. E2O's strategy is simple -- manufacture in volume to achieve low prices.

Other 850nm VCSEL manufacturers agree. "We're as good as anyone else, but there's no reason to say our VCSELs are better," says Geoff Callow, a technical marketing specialist at Mitel Corp. (NYSE/Toronto: MLT). "It's not what you have, it's what you do with it that counts," he adds.

In the end, choice of an 850nm single VCSEL boils down to a few basic variables, such as price, optical output power, price, modulation speed, and the color of the salesman's socks.

When it comes to making VCSEL arrays, there are a few more variables. The choice also depends on the equipment for which the transmitter is intended. For instance, one vendor might sell a 1x12 array with an aggregate capacity of 10 Gbit/s. (Each individual device operates at 1.25 Gbit/s; the rest is overhead). Another vendor can offer the same aggregate capacity from a 1x4 array by using devices that each operate at 3.125 Gbit/s. Yet another product is available that uses a combination of 2.5 Gbit/s lasers in a 1x8 array. Standards are still evolving in this space.

A couple of vendors are working on methods for increasing output power. They aren't likely to compete with the 850nm vendors because longer distances can be reached more effectively by going to longer wavelengths rather than by increasing output power. High-power applications would include 980nm lasers for pumping fiber amplifiers (still classed as short-wavelength VCSELs because they use the same materials as the 850nm devices).

Vendors

The Established Players

Emcore Corp.
  • Gained VCSEL expertise through its acquisition of Mode, a spinoff from Sandia National Laboratories in 1997
  • In August 2000, announced the availability of a 1x4 VCSEL array capable of up to 10 Gbit/s and a 1x12 array with a data rate of 30 Gbit/s
  • Max data rate 3.125 per channel
  • Has a joint development and marketing agreement with JDS Uniphase Corp. (NYSE: JDSU)
  • Customers include Agilent Technologies Inc. (NYSE: A), which began sampling parallel optical transceivers in November 2000 (see Agilent Unveils 30-Gig Optic Modules). The duo have a three-year supply agreement

    Honeywell Inc. (NYSE: HON)
  • Honeywell Sensing and Control was the first company to commercialize VCSEL technology
  • It's the world's largest VCSEL component supplier, it claims. Electronicast's study backs this up
  • Sells a lot of VCSELs for sensing and other non-telecom applications
  • Plans to offer VCSEL arrays in the future (no specs available yet)

    Gore Photonics Inc., a subsidiary of W.L. Gore and Associates Inc.
  • Gore got into VCSELs when it acquired a company called Optical Concept, which was started by, and just up the road from, the University of California, Santa Barbara (UCSB)
  • Offers single VCSELs and 1x12 arrays Infineon Technologies AG (NYSE: ISX) (formerly Siemens Semiconductor)
  • Makes VCSEL chips for internal consumption
  • Sells a transceiver called PAROLI containing a 1x12 VCSEL array with an aggregate data rate of up to 15 Gbit/s
  • Could be having trouble with its VCSEL arrays. Brightlink Networks Inc. says it ordered some PAROLI modules in 1999 and still hasn't received them. Infineon did not respond to requests for an interview.

    Mitel Corp. (NYSE/Toronto: MLT)
  • Mitel is the second largest manufacturer of VCSEL chips. Electronicast reckons that between them, Honeywell and Mitel produce 75 percent of all VCSEL chips.
  • In 1996, Mitel acquired the foundry of ABB Hafo in Sweden, where it now produces VCSELs
  • Offers single VCSELs and arrays up to 1x12
  • Mitel contends it's got the edge when it comes to making VCSEL arrays. It has a technique for aligning a 1x4 array end-on with a second 1x4 array, to create a 1x8 array. (Add a third chip to create a 1x12 array and so on). That's a major strength because it improves the yield of the manufacturing process considerably, says Mitel's Geoff Callow, a technical marketing specialist. "If you make a chip that's twice as big, you get considerably less than half the yield. So using four rather than twelve gives us a distinct advantage," he says.

    The Newcomers

    Alvesta Inc.
  • Incorporated in April 1999 by Dubravko Babic, John Bowers, and Russell Bik. It's an impressive lineup. Babic is credited with fabricating the first continuous-wave operating long-wavelength VCSEL in 1995, while at UCSB. Dr. Bowers is currently professor of Electrical and Computer Engineering at UCSB and heads up the university's Multidisciplinary Optical Switching Technology Center. Past achievements include leading the team that demonstrated the first 8- and 16-Gbit/s transmission systems at AT&T Bell Laboratories (now Lucent Technologies Bell Laboratories). In 1996, he founded Terabit Technologies and as CEO led the company through product development to successful acquisition by Ciena Corp. (NYSE: CIEN). Bik is ex-Intel Corp., Sun Microsystems Inc., and Kleiner Perkins Caufield & Byers.
  • March 2000: announced its first product, a 10-Gbit/s small form factor transceiver. Inside is a 1x4 VCSEL array plus detectors, each element operating at 3.125 Gbit/s.

    Avalon Photonics
  • Spun out of the Centre Suisse d'Electronique et de Microtechnique (CSEM), Zürich, in 1999 (formerly the Paul Scherrer Institüt).
  • Though the company is new, it leverages the experience from CSEM, which started VCSEL development in 1994 and had sales in 1997.
  • CSEM has also developed a technology for making embossed microlenses, which narrows the transmission angle from 12 degrees to less than half a degree.
  • Offers a range of devices from 850 to 960 nanometers in wavelength and in arrays up to 1x10 and 8x8.



    E2O Communications Inc.
  • Founded in 1998
  • October 2000: Introduced 1x4 array with an aggregate capacity of 10 Gbit/s
  • Also in October, won $38.5 million cash injection. Lead investor was New Enterprise Associates (see E2O Closes $38.5M Third Round).

    Peregrine Semiconductor Corp.
  • Founded in 1990, Peregrine specializes in silicon-on-insulator electronics
  • Dabbles in VCSELs. Has produced prototype 1x4 arrays flip-chip bonded to CMOS-on-sapphire drive circuitry. Each channel in the array operates at 3.125 Gbit/s



    Novalux Inc.
  • Claims to have a technique for getting high powers out of VCSELs, which it calls the "Novalux extended cavity surface-emitting laser" (NECSEL). Novalux won't explain how this works, but does say that it's increased the area that emits light inside the laser (see Novalux Promises Cheaper Lasers and Laser Startup Bags $109 Million)
  • First product is a pump laser at 980nm (for pumping fiber amplifiers)


    PicoLight Inc.
  • PicoLight was started by Jack Jewell and Stan Swirhun, both founders of Vixel Corp. Vixel was the first company committed to commercializing VCSELs, they claim. Neither party will explain what happened in the transition from Vixel to PicoLight. (Incidentally, since it was acquired by the Fibre Channel division of Western Digital Corp., Vixel has moved into systems and no longer makes VCSELs.)
  • According to Jewell, PicoLight pioneered a more advanced type of VCSEL using a technique called oxide-confinement, which is now widely used in the industry. He likens the process to a steam bath: The material is subject to a water-saturated environment at 400 degrees Centigrade. As a result, a layer of aluminium oxide forms on the outside of the device, giving it better optical and electrical properties.
  • Has two products shipping in volume: a 1.25-Gbit/s single VCSEL, and a 2.5-Gbit/s version. Arrays will follow soon.

    Siros Technologies Inc. (formerly Opitek)
  • Siros is developing VCSELs primarily for optical data storage applications
  • It uses technology licensed from Lucent Technologies Inc., which makes it possible to achieve very high power densities, it claims (see Lucent, Siros Extend Laser Pact and Siros Claims VCSEL Breakthrough). The technique is called the Very Small Aperture Laser (VSAL), and it basically concentrates the emission through a very small hole in the top mirror. Robert Thornton, Siros's director of laser development says, "The architecture underlying this device could be used to solve key problems associated with maintaining single wavelength operation when VCSELs are operated at high power levels in excess of 5 milliwatts." TrueLight Corp.
  • Founded in 1997 in Hsinchu, Taiwan, by a team headed by Dr. Kai-Feng Huang and Dr. Kuochou Tai, both from National Chiao-Tung University
  • Offers single VCSELs at 780, 850, and 980 nm. Arrays under development
  • Claims its devices are high-power: up to 3 milliwatts at 12 milliamp current, up to 8 milliwatts at 30 milliamp current

    Previous Page
    6 of 8
    Next Page
  • Stockholm syndrome 12/4/2012 | 8:59:42 PM
    re: Laser Blazers Well, no mentioning of players like:
    - Altitun
    - NUFO
    I am not convinced that the picture is complete.
    Please fill me in!


    Peter Heywood 12/4/2012 | 8:59:40 PM
    re: Laser Blazers The article was an in-depth look at VCSELs - vertical cavity surface emitting lasers. Altitun (which was acquired by ADC) and NUFO don't make VCSELs.

    I did a more general survey of tunable lasers a while back. See:

    http://www.lightreading.com/do...

    Use our search engine on "tunable lasers", "altitun" or "NUFO" you'll find loads more info.

    HOME
    Sign In
    SEARCH
    CLOSE
    MORE
    CLOSE