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CAMPBELL,
CA -- November 21, 2000 -- Summit
Microelectronics Inc has introduced the industry's
first laser control device which compensates for
the operating temperature of the laser itself, the
SML2108
adaptive power controller. This device will greatly
simplify the design and implementation of
high-speed fiber-optic transceivers by eliminating
the need for costly thermal electric
coolers.
"The
design of high fiber-optic transceivers has been
complicated by the lack of a means of adjusting the
modulation current of the laser based upon the
temperature of the laser itself to maintain a
constant extinction ratio," stated Rick Orlando,
president and chief executive officer of Summit.
"This has led to the widespread use of thermal
electric coolers to attempt to hold the laser at a
constant temperature, an approach which increases
the footprint, cost and power consumption of the
transceiver."
Adaptive
thermal control of the laser has two distinct
problems. The first is the method used to measure
the temperature of the laser itself, rather than
the ambient temperature. Summit's unique approach
actually directly measures the bias current of the
laser to determine the temperature of the laser
itself.
Once
the temperature of the laser is determined, the
second challenge is how to compensate control the
modulation current, since each individual laser
will have its own unique non-linear characteristic.
The Summit SML2108
uses a 256 X 8 look-up table, which is programmed
at the testing of the transceiver, to generate 256
individual compensation factors. The output of this
table can is used to drive a modulation current
source which can be configured to operate in 0 - 5
mA amps for Vicsel applications and 0 -100mA m amp
for long-haul applications.
The
SML2108
also includes an automatic power control circuit to
maintain constant average power through bias
current control. A 10-bit nonvolatile DAC is used
in the device to set the initial bias current
values. The integration of both bias and modulation
current control eliminates the need for these
functions to be placed on the laser modulating
circuit, allowing the design and use of more
simplified laser drivers. All configuration of the
device is accomplished through and industry
standard I2C interface.
"The
SML2018 represents a major change in the way fiber
optics transceivers will be designed in the
future," continued Orlando. "The domination of
fiber optics in the networking and communications
market can only be realized if the transceivers
become smaller, cheaper and lower power. The first
step in this evolution is to eliminate the need for
the thermal electric cooler while maintaining
optimized performance at a wide range of ambient
temperatures. The SML2108 enables this
evolution"
Pricing and Availability
The
SML2108
laser diode adaptive power controller offers 3V or
5V operation and is available now in die form, as a
a 48-lead TQFP. Quantity pricing is $9.40 in 1000
piece quantities; $7.50 in 10,000 piece
quantities.
About Summit
Summit
Microelectronics develops semiconductors that
manage the power functions in communications system
equipment. Using Summit's analog proprietary
technology, customers can achieve carrier-class
availability, the highest standard of reliability
available today for telecommunications, data
communications and Internet
applications.
Founded
in 1997, Summit is headquartered in Campbell,
California. The Company is ISO 9001 certified and
is in the process of gaining ISO 14000 and STACK
certification. Summit's website is www.summitmicro.com.
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Summit
Microelectronics, Inc.
1717 Fox Drive
San Jose, CA 95131-2312
Tel: +1.408-436-9890
Email:
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