Datacom companies are making networking even easier for data-center
companies by attaching optical transceivers permanently to the ends of fiber
cables, thus making active optical cables.
AOCs use the same electrical inputs as traditional copper
cables—they plug into the familiar
USB and HDMI ports, among
others—but they carry signals
over optical fiber for one-fourth to
one-sixth of the mass and bulk of
metal wires.
According to Tom Rossi, an
independent technology consultant in California (U.S.A.), the
typical AOC operates at 850 nm
and incorporates VCSELs within
the transceivers at each end of the
cable. AOCs incorporate either
single-mode or multi-mode fiber.
Besides HDMI video and
USB protocols, AOCs are made
for InfiniBand, a switched-fabric
architecture used in high-performance computing, and Display-Port, a competitor to HDMI for computer-video interfacing.
Rossi expects that most of these active cables will go into data
centers rather than fiber-to-the-home applications.
Annual production of VCSELs for AOCs could rise from
5. 2 million units in 2010 to 170 million in 2014, Rossi predicted in a report for Information Gatekeepers Inc. of Boston
(Mass., U.S.A.). The most common VCSELs in this product
area will be rated at 5 Gbps.
Getty Images
Networking the future
This short article could not possibly cover every single type of laser-based optical communications.
For example, free space optics is a
small part of the communications
market, but it could provide up to
1.25-Gbps connectivity between
buildings in urban areas and on
the military battlefield, where fiber
cables can’t be laid. Also, future
interplanetary spacecraft may use
free-space laser links to transmit
vast amounts of data back
to Earth.
Undoubtedly, both core net-
works and datacom systems will
continue to move away from elec-
tronics and toward ever-faster optical technology for the fore-
seeable future. Researchers will continue to shrink communi-
cations lasers, make them out of more exotic semiconductors,
integrate them into tinier devices and move them closer to end
users. To future generations, communications networks that
don’t rely on lasers will seem as quaint as the town crier, the
telegraph and the Pony Express. t
Patricia Daukantas ( pdauka@osa.org) is the senior writer/editor of Optics &
Photonics News.
[ References and Resources ]
>> J. Gowar. Optical Communication Systems, second ed. (New York:
Prentice Hall, 1993).
>> D.A. Ackerman et al. “Telecommunication Lasers,” in Optical Fiber
Communications IV, ed. by I.P. Kaminow and T. Li (San Diego: Academic Press, 2002).
>> P. Kner et al. “VCSELs Go the Distance,” Opt. Photon. News 13( 3), 44
(March 2002).
>> B.E. Lemoff. “Coarse WDM Transmitters,” Opt. Photon. News 13( 3),
S- 8 (OPN Trends, March 2002).
>> D. Killinger. “Free Space Optics for Laser Communication Through the
Air,” Opt. Photon. News 13( 10), 36 (October 2002).
>> L.A. Zenteno and D. T. Walton. “Novel Fiber Lasers and Applications,”
Opt. Photon. News 14( 3), 38 (March 2003).
>> T. Jensen et al. “Testing DWDM Components for Loss and Dispersion,”
Opt. Photon. News 14( 7), 36 (July 2003).
>> F.-T. An et al. “SUCCESS: A Next-Generation Hybrid WDM/TDM
Optical Access Network Architecture,” J. Lightwave Technol. 22, 2557
(2004).
>> K. Sato. “Key Enabling Technologies for Future Networks,” Opt. Photon. News 15( 5), 34 (May 2004).
>> A.A. Kachanov et al. “Tunable Diode Lasers: Expanding the Horizon for
Laser Absorption Spectroscopy,” Opt. Photon. News 16( 7), 44 (
July-August 2005).
>> J. Buus and E.J. Murphy. “Tunable Lasers in Optical Networks,” J.
Lightwave Technol. 24, 5 (2006).
>> J. Hecht. “Slow Light and Fast Data Links: Report from OFC 2006,”
Opt. Photon. News 17( 6), 22 (June 2006).
>> H. Hemmati. “Interplanetary Laser Communications,” Opt. Photon.
News 18( 11), 22 (November 2007).
>> The Light Brigade. “Fiber Optic Active Devices,” DVD (The Light Brigade, Tukwila, Wash., U.S.A., 2008).
>> D.C. Brown and J. W. Kuper. “Solid-State Lasers: Steady Progress
Through the Decades,” Opt. Photon. News 20( 5), 36 (May 2009).
>> B. Jalali et al. “Green Silicon Photonics,” Opt. Photon. News 20( 6), 18
(June 2009).
>> OFC/NFOEC Chairs. “A Snapshot of Optical Communications,” Opt.
Photon. News 21( 1), 24 (January 2010).
