4 Lucent Technologies Inc.
Data Sheet
1241/1243/1245-Type Uncooled Laser Transmitter September 1999
Functional Overview
(continued)
Since most applications operate at very high data
rates, high-frequency design techniques need to be
used to ensure optimum performance from the trans-
mitter and interfacing circuitry. Input signal paths
should be kept as short and as straight as possible; dif-
ferential signal lines should be equal in length, and
controlled-impedance stripline or microstrip construc-
tion should alwa ys be used when laying out the printed-
wiring board traces for the data lines. The Recom-
mended User Interfaces section of this data sheet
shows several methods of interfacing to the transmitter.
Power Supplies
The transmitter is configured f or operation from either a
single +5 V po wer supply or a single –5 V pow er supply.
F or positive po wer supply operation, connect Vcc to the
+5 V power supply and connect V
EE
to ground or circuit
common. For operation from a –5 V power supply, con-
nect V
CC
to ground and connect V
EE
to the –5 V power
supply. Whichever option is chosen, the V
CC
or V
EE
con-
nection to the transmitter should be well filtered to pre-
vent power supply noise from interfering with
transmitter operation.
Transmitter Specifications
Optical Output Power
During manufacture, the optical output power of every
transmitter is tuned to the typical value specified in the
data sheet for that particular transmitter code. The tun-
ing is performed at room ambient and a power supply
voltage of 5 V. The minimum and maximum values
listed in the data sheet for each code group reflect the
worst-case limits that the transmitter is expected to
operate within over its lifetime and over the allowed
power supply and the operating temperature range.
Every transmitter shipped receives a final test, which
includes a SONET eye-mask test at either the OC-3
(STM-1) data rate of 155.52 Mbits/s, the OC-12
(STM4) data rate of 622.08 Mbits/s, or the fibre channel
FC-0 data rate of 1062.5 Mbits/s. The eye-mask test is
meant to examine the performance of the transmitter's
output optical wa v eform relativ e to a minimum data pat-
tern eye opening.
Connector Options
The standard optical fiber pigtail is 8
µ
m core single-
mode fiber having a 0.036 in. (914
µ
m) diameter tight-
buffered outer-jacket. The standard length is 39 in.
±
4 in. (1 m
±
10 cm) and can be terminated with either
an SC or FC-PC optical connector. Other connector
options ma y be av ailable on special order . Contact your
Lucent Account Manager for ordering information.
Handling Precautions
CAUTION: This device is susceptible to damage as
a result of electrostatic disc harge (ESD).
Take proper precautions during both
handling and testing. Follow guidelines
such as JEDEC Publication No. 108-A
(Dec. 1988).
Although protection circuitry is designed into the
device, take proper precautions to avoid exposure to
ESD. Lucent employs a human-body model (HBM) for
ESD-susceptibility testing and protection-design evalu-
ation. ESD voltage thresholds are dependent on the
critical parameters used to define the model. A stan-
dard HBM (resistance = 1.5 k
Ω
, capacitance = 100 pF)
is widely used and, therefore, can be used for compari-
son purposes. The HBM ESD withstand voltage estab-
lished for the 1241-/1243-Type Transmitter is
±
1000 V.
Transmitter Processing
The transmitter can withstand normal wave-soldering
processes. The complete transmitter module is not her-
metically sealed; therefore, it should not be immersed
in or sprayed with any cleaning solution or solvents.
The process cap and fiber pigtail jacket deformation
temperature is 85
°
C. Transmitter pins can be wave-
soldered at maximum temperature of 250
°
C for
10 seconds.
Installation Considerations
Although the transmitter features a robust design, care
should be used during handling. The optical connector
should be kept free from dust, and the process cap
should be kept in place as a dust cover when the
device is not connected to a cable. If contamination is
present on the optical connector, canned air with an
extension tube can be used to remove any debris.
Other cleaning procedures are identified in the techni-
cal note,
Cleaning Fiber-Optic Assemblies
(TN95-
010LWP).