Planar
External-Cavity (PLANEX) Laser
Delivers 80 km 10 Gbps Transmission in Small Form Factor
For Industry's Lowest Cost-Per-Port
Santa Clara, CA, December
15, 2004 - RIO, Inc. (Redfern Integrated
Optics) has demonstrated a new type of directly modulated laser,
based on Planar External-Cavity (PLANEX) Laser technology,
offering a new low-cost choice for small form factor 10 Gbps
optical interfaces that reliably achieve 80 km transmission
distances over standard single mode fiber without the need
for dispersion compensation.
RIO's proprietary design approach uses a Planar Lightwave
Circuit (PLC) with an integrated Bragg grating and a high-performance
low-cost gain chip (or SOA - Semiconductor Optical Amplifier)
to form the laser cavity. The gain chip functions as an optical
amplifier and the Bragg grating acts as both a partially reflecting
mirror and a wavelength locker. This enables the laser to output
a controlled chirp waveform at a very well defined and stable
wavelength. The direct modulation approach also reduces complexity
and cost while providing output power as well as power dissipation
advantages over externally modulated lasers.
According to Radu Barsan, President and
CEO of RIO Inc., "Currently
the high cost and/or limited performance of lasers used in
10Gbps pluggable transceivers and transponders is inhibiting
the growth of extended reach and DWDM 10Gbps deployments. By
taking advantage of well developed fabrication processes of
optical components on silicon wafers to produce the PLC component
of the ECL, RIO is able to improve transmission performance
while simultaneously driving down component costs."
Until now, externally modulated lasers have been the only
viable solution for transmission in the 1550nm band for implementing
extended reach and DWDM optical networks at 10Gbps. Externally
modulated lasers using a DFB laser with a Lithium Niobate modulator
are large, expensive and require a high power driver. Monolithic
or hybrid integrated electroabsorption modulated lasers (EMLs)
are expensive, especially for distances up to 80 km, and prohibitively
expensive for narrow grid DWDM. EMLs have limited output power,
which can increase the need for additional erbium-doped fiber
amplifiers (EDFAs) or more expensive EDFAs. External modulation
also dissipates more power than direct modulation, because
the laser is turned on to full power at all times and the external
modulator consumes additional power to operate. The production
yield difficulties associated with the monolithic combination
of laser and modulator on the same chip means that EMLs will
be only marginally capable of meeting volume and cost requirements
for SONET and DWDM performance.
In contrast, RIO's ECL technology offers significant manufacturing
cost reduction. Unlike DFB and EML manufacturing, where the
wavelength decision must be made at the early stage of wafer
processing, the ECL wavelength is set during the packaging
process, using pre-tested PLC components. It is thus possible
to increase packaging yield and, as a result, reduce overall
cost. In addition, postponing the wavelength decision until
the packaging step significantly reduces the lead time for
DWDM ECLs.
RIO's PLANEX technology has been implemented
in the smallest TOSA formats specified by the XFP and XMD
MSAs for 40km and 80km. At the 40km distance, RIO's ECL approach
offers a better than 30% cost advantage over comparable EML
devices. RIO's scalable and high-yield manufacturing approach
provides even greater cost benefits for 80 km and DWDM applications.
The technology is truly a "platform" technology,
in that it can scale to multiple applications with minimum
incremental investments.
An overview whitepaper on the underlying technology and implementation
of RIO's PLANEX-based optical interfaces can be requested by
contacting the Company.
About RIO Inc.
RIO Inc. is an industry leader in the development of new semiconductor
and optical transmission technologies that enable transceivers
to deliver telecom-grade performance with datacom economics.
RIO is headquartered in Santa Clara, CA, with PLC wafer fabrication
facilities in Sydney, Australia.
For more information, please visit www.rio-inc.com.
For More Information, contact
Radu Barsan, President and CEO
408-970-3500 ext.350
Jim Hunt
Phone: 253-857-7242
Email: jimhunt@sitmark.com
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