Data Sheet

September 1999

1241/1243/1245-Type Uncooled Laser Transmitter

Offering multiple output power options and SONET/SDH com-
patibility, the 1241/1243-Type Uncooled Laser Transmitter is
manufactured in a 20-pin, plastic DIP with a single-mode fiber
pigtail.

Features

Backward compatible with 1227/1229/1238-Type
Laser Transmitters

Space-saving, self-contained, 20-pin DIP

Uses field-proven, reliable InGaAsP MQW laser

Requires single 5 V power supply

SONET/SDH compatible

Uncooled laser with automatic optical power con-
trol for constant output power over case tempera-
ture range

No thermoelectric cooler required; reduces size
and power consumption

Uses low-power dissipation CMOS technology

Qualified to meet the intent of Bellcore reliability
practices

Operates over data rates to 1062.5 Mbits/s (NRZ)

Operation at 1.3 µm or 1.55 µm wavelength

Typical average output power options of 11 dBm,
8 dBm, 5 dBm, 2 dBm, and 0 dBm

ECL compatible, differential inputs

Operating temperature range of 40 °C to +85 °C

Transmitter-disable option

Applications

Telecommunications
-- Inter- and intraoffice SONET/ITU-T SDH
-- Subscriber loop
-- Metropolitan area networks

High-speed data communications
-- Fibre channel (FC-0)

Agere Systems Inc.

Data Sheet

1241/1243/1245-Type Uncooled Laser Transmitter

September 1999

Description

The 1241/1243/1245-type Laser Transmitters are
designed for use in transmission systems and high-
speed data communication applications. Used in
intraoffice and intermediate-reach applications, the
transmitters are configured to operate at SONET rates
up to OC-12, as well as at ITU-T synchronous digital
hierarchy (SDH) rates up to STM-4. Specific versions
are also capable of operating up to 1062.5 Mbits/s.

The transmitter meets all present Bellcore GR-253-
CORE requirements, ANSI T1.117-1991 SONET sin-
gle-mode, and the ITU-T G.957 and G.958 recommen-
dations. (See Table 5 to select transmitters for the
various SONET/SDH segments.)

The transmitter requires a single power supply (+5 V or
5 V) and operates over data rates of 1 Mbits/s to
622 Mbits/s (NRZ). Automatic power control circuitry
provides constant optical output power over the operat-
ing case temperature range. The automatic power con-
trol circuitry also compensates for laser aging. The
optical wavelength tolerance at 25 °C is 1310 nm. The
temperature coefficient of wavelength for 1.3 µm Fabry-
Perot transmitters (1241-Type) is approximately
0.4 nm/°C. The temperature coefficient of wavelength
for 1.3 µm and 1.55 µm distributed-feedback (DFB)
transmitters (1243/1245-Type) is approximately
0.1 nm/°C.

Transmitters are available for operation over several dif-
ferent temperature ranges from 40 °C to +85 °C. Man-
ufactured in a 20-pin DIP, the transmitter consists of a
hermetic, InGaAs laser and a single CMOS driver IC.
The low-power consumption circuit provides modula-
tion, automatic optical output power control, and data
reference. The module can be driven by either ac- or
dc-coupled data in single-ended or differential configu-
ration. (See Recommended User Interfaces section for
typical connection schemes.) The laser bias and back-
facet monitor currents are electrically accessible for
transmitter performance monitoring. The transmitter
optical output may be disabled by a logic-level input.

Functional Overview

Transmitter Circuit Description and
Operation

Figure 1 shows a simplified schematic of the transmit-
ter; pin information is listed in Table 1. The laser within
the transmitter is driven by a single CMOS integrated
circuit, which provides the input data signal reference
level with automatic, temperature-compensated laser
bias, and modulation-current control. A back-facet pho-

todetector diode within the laser module provides an
indication of the laser's average optical output power.
The back-facet diode current is accessible as a voltage
proportional to photocurrent through pins 17 and 19 on
the transmitter. The back-facet diode also forms part of
the feedback control circuit, which helps maintain con-
stant output power.

The laser bias current is accessible as a dc-voltage by
measuring the voltage developed across pins 2 and 4
of the transmitter. Dividing this voltage by 10

will

yield the value of the laser bias current. This value will
change up or down in response to operating tempera-
ture, power supply voltage, data pattern, and laser
aging characteristics.

Table 1. Pin Descriptions

* Pins designated as no user connection should not be tied to

ground or any other circuit potential.

Laser back-facet and bias monitor functions are customer-use

options that are not required for normal operations of the trans-
mitter. They are normally used during manufacture and for
diagnostics.

Pin Number

Name

No user connection

Laser bias monitor (+)

No user connection

Laser bias monitor ()

Transmitter disable

No user connection

Case ground (RF ground)

DATA

Laser back-facet monitor ()

Laser back-facet monitor (+)

No user connection

Data Sheet
September 1999

Agere Systems Inc.

1241/1243/1245-Type Uncooled Laser

Functional Overview

(continued)

1-868(C).h

Figure 1. Simplified Transmitter Schematic Input Data

LASER BACK-FACET MONITOR VOLTAGE

15 k·

(2)

(4)

(+)

()

15 k·

LASER BIAS MONITOR VOLTAGE

15 k·

(19)

(17)

(+)

()

15 k·

BAND GAP

REFERENCE

AUTOMATIC POWER

CONTROL CIRCUITRY

INPUT DATA

COMPARATOR

MODULATION

CIRCUITRY

TEMPERATURE
SENSOR

BIAS

LASER

BACK-FACET

DETECTOR

FIBER PIGTAIL

10 ·

DATA

(16)

(7)

(15)

TRANSMITTER

DISABLE

1.3 V

30 k·

DATA

MOD

Input Data

Data enters the transmitter through a comparator.
These inputs have internal pull-down resistors to a volt-
age reference that is 1.3 V below V

. This configura-

tion allows the transmitter to be driven from either a
single-ended or a differential input signal. Since the
input is a comparator instead of a gate, the absolute
input signal levels are not important when the inputs
are driven differentially. When driven single-ended,
however, the input signal voltage should be centered
around V

1.3 V to eliminate pulse-width distortion.

With a single-ended input, either input can be used and
the unused input can be left as an open circuit due to
the internal reference shown in Figure 1. The optical
output signal will be in the same sense as the input
data--an input logic high turns the laser diode on and
an input logic low turns the laser diode off. However, if
the negative input is used with a single-ended data

input signal, the optical signal will be the complement
of the data input signal.

The differental inputs of the 1241 Gbit versions are ter-
minated internally with 100

between the DATA and

DATA inputs.

Minimum Data Rate

Because the modulation and bias control circuitry are
influenced by the input data pattern, the standard
transmitter cannot be used in burst-mode type applica-
tions. For burst-mode applications, please contact your
Agere Account Manager. The minimum data rate
(pseudorandom data, 50% average duty cycle) for the
1241/1243/1245-Type Transmitters is approximately
1 Mbit/s.

Agere Systems 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 always 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 for operation from either a
single +5 V power supply or a single 5 V power sup-
ply. For positive power supply operation, connect Vcc to
the +5 V power supply and connect V

to ground or

circuit common. For operation from a 5 V power sup-
ply, connect V

to ground and connect V

to the 5 V

power supply. Whichever option is chosen, the V

connection to the transmitter should be well filtered

to prevent 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 waveform relative to a minimum data pat-
tern eye opening.

Connector Options

The standard optical fiber pigtail is 8 µm core single-
mode fiber having a 0.036 in. (914 µm) 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 may be available on special order. Contact your
Agere Account Manager for ordering information.

Handling Precautions

CAUTION: This device is susceptible to damage as

a result of electrostatic discharge (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. Agere 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

, 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).

Agere Systems Inc.

Data Sheet
September 1999

1241/1243/1245-Type Uncooled Laser

Absolute Maximum Ratings

Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are abso-
lute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operations sections of the data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability.

* With V

connected to 5 V, V

must be at 0 V; with V

connected to +5 V, V

must be at 0 V.

Specification depends upon the code ordered. The device is capable of a cold start at 40 °C; specifications are met

after a warm-up time determined by the system thermal design.

Characteristics

Minimum and maximum values specified over operating case temperature range at 50% duty cycle data signal and
end of life (EOL). Typical values are measured at beginning-of-life (BOL) room temperature unless otherwise noted.

Table 2. Electrical Characteristics

1. With V

connected to 5 V, V

must be at 0 V; with V

connected to +5 V, V

must be at 0 V.

2. Input measured from V

with 50

load to (V

2 V). 10K, 10K H, and 100K ECL compatible.

3. Between 10% and 90% (50% duty cycle) where t is the bit period in ns.
4. The transmitter is normally enabled and only requires an external voltage to disable.
5. Time measured from rising edge of disable signal until optical output (laser diode) has turned off.
6. Time measured from falling edge of enable signal until optical output has stabilized at nominal output power level.
7. The laser bias current is obtained by dividing the bias voltage by the 10

current-sensing resistors. (See Figure 1.) When measuring these

voltages or using them in conjunction with alarm circuits, use a high-input impedance device.

8. The laser back-facet monitor voltage is a scaled output that tracks the transmitter optical output power.

Parameter

Symbol

Min

Max

Unit

Supply Voltage

5.5

Operating Case Temperature Range

°C

Storage Case Temperature Range

stg

°C

Lead Soldering Temperature/Time

250/10

°C/s

Relative Humidity (noncondensing)

Minimum Fiber Bend Radius

1.00 (25.4)

in. (mm)

Parameter

Symbol

Min

Typ

Max

Unit

Power Supply Voltage

4.75

5.0

5.50

Power Supply Current Drain

TOTAL

130

Input Data Voltage:

Low
High

1.81
1.16

--
--

1.47
0.88

V
V

Input Transition Time

t/4

Transmitter Disable Voltage

2.0

Transmitter Enable Voltage

+ 0.8

Output Disable Time

0.20

µs

Output Enable Time

2.00

µs

Laser Bias Voltage

0.01

0.06

0.70

Laser Monitor Voltage (50% duty cycle)

0.01

0.05

0.20

Agere Systems Inc.

Data Sheet

September 1999

1241/1243/1245-Type Uncooled Laser Transmitter

Characteristics

(continued)

Table 3. Optical Characteristics

1. Output power definitions and measurement per ITU-T Recommendation G.957 and G.958.
2. Ratio of logic 1 to logic 0 power levels.
3. Between 10% and 90% (50% duty cycle).
4. Root-mean-square spectral width accounts for modes up to and including those 20 dB down from the central mode.

(Applies to 1241-Type only.)

5. Applies to 1243/1245-Type only.

Recommended User Interfaces

1-496(C).c

* Locate these components as close to DATA/DATA inputs as possible.

Note: The 1241 gigabit version does not require the external 50

terminations since this termination is included inside the module.

Figure 2. dc-Coupled, Differential Input

Parameter

Symbol

Min

Typ

Max

Unit

Average Power Output Options

See Ordering Information.

dBm

Extinction Ratio

Optical Rise and Fall Times

OC-3/STM-1
OC-12/STM4
1062.5 Mbits/s

, t

--
--
--

1.0
0.5

0.37

ns
ns
ns

Center Wavelength

See Ordering Information.

RMS Spectral Width

Side-mode Suppression Ratio

SMSR

ECL
DRIVER

TRANSMITTER

50 ·*

360 ·

VEE

50 ·*

0.1 µF

50 · MICROSTRIP OR STRIPLINE-
CONTROLLED IMPEDANCE TRACES

Agere Systems Inc.

Data Sheet
September 1999

1241/1243/1245-Type Uncooled Laser

Recommended User Interfaces

(continued)

1-497(C)

Note: Input can also be connected to DATA; unused input pin remains unconnected.

(622 Mbits/s and below only.)

Figure 3. dc-coupled, Single-Ended Input

1-498(C)

* This network introduces a slight offset between DATA and DATA, which turns the laser

transmitter off when there is no data present at the inputs. (622 Mbits/s and below only.)

Figure 4. ac-Coupled, Single-Ended Input

Qualification and Reliability

To help ensure high product reliability and customer satisfaction, Agere Systems is committed to an intensive qual-
ity program that starts in the design phase and proceeds through the manufacturing process. Optoelectronics mod-
ules are qualified to Agere Systems internal standards using MIL-STD-883 test methods and procedures and using
sampling techniques consistent with Bellcore requirements. The 1241/1243/1245 series of transmitters have
undergone an extensive and rigorous set of qualification tests. This qualification program fully meets the intent of
Bellcore reliability practices TR-NWT-000468 and TA-NWT-000983. In addition, the design, development, and man-
ufacturing facility of the Optoelectronics unit at Agere Systems has been certified to be in full compliance with the
latest ISO-9001 Quality System Standards.

50 ·

1.0 µF

C C

2 V

(CUSTOMER

SU PPLIED )

50 · COAX

OR 50 ·

STRIPLIN E

TRA NSMITTER

50 ·

50 · COAX
OR 50 ·

STRIPLINE

1.0 µF

619 ·

27 ·

1960 ·

TRANSMITTER

Agere Systems Inc.

Data Sheet
September 1999

1241/1243/1245-Type Uncooled Laser

Laser Safety Information

Class I Laser Product

All versions of the 1241/1243/1245-Type transmitters are Class I laser products per CDRH, 21 CFR 1040 Laser
Safety requirements. The 1241/1243/1245-Type transmitters have been classified with the FDA under accession
number 8720009. All versions are Class I laser products per IEC 825-1:1993.

CAUTION: Use of controls, adjustments, and procedures other than those specified herein may result in

hazardous laser radiation exposure.

This product complies with 21 CFR 1040.10 and 1040.11.
8.8 µm single-mode pigtail with connector
Wavelength = 1.3 µm
Maximum power = 1.6 mW

Notice

Unterminated optical connectors may emit laser radiation.

Do not view with optical instruments.

Table 4. Ager e Transmitters for SONET/SDH Applications

* Full SONET/SDH compliance, 40 °C to +85 °C.
Full SONET/SDH compliance, 20 °C to +70 °C.

Connector

Type

1.3 µm Transmitter Type

1.55 µm Transmitter Type

Short and Intermediate Reach

(<2 km and ~15 km)

Long Reach

~40 km

Long Reach

~80 km

OC-3/

STM-1

OC-12/

STM-4

OC-3/

STM-1

OC-12/

STM-4

OC-3/

STM-1

OC-12/

STM-4

FC-PC

1241FAUC

1241FBUC

1243FAFD

1243FBDC

1245FAFC

1245FBDC

1241CAUC

1241CBUC

1243CAFD

1243CBDC

1245CAFC

1245CBDC

Agere Systems Inc.

Data Sheet

September 1999

1241/1243/1245-Type Uncooled Laser Transmitter

Ordering Information

Table 5. 1241/1243/1245-Type Transmitter Ordering Information

for these codes is 2.5 nm maximum. All other 1241-type codes are 4 nm maximum.

OC-3/STM-1 Transmitter Codes

Operating

Case Temp.

Range (°C)

Average Output

Power

(dBM)

Center

Wavelength

(nm)

Connector

122x

Equivalent

Product

Order

Code

Comcode

Min

Max

Min

Typ

Max

Min

Max

1290

1330

FC-PC

1227AE

1241FADC

108123449

1290

1330

1227AF

1241CADC

108123480

1280

1335

FC-PC

1227YA

1241FAFC

108123357

1280

1335

1227YB

1241CAFC

108123373

1260

1360

1227CA

1241CALC

108123324

1260

1360

FC-PC

1227C

1241FALC

108123563

1480

1580

1229CB5

1245CAFC

108400409

1480

1580

FC-PC

1229FB5

1245FAFC

108400417

1280

1335

1227YD

1243CAFD

108123423

1280

1335

FC-PC

1227YE

1243FAFD

108123415

1260

1360

1227FB

1241CAPC

108123282

1260

1360

FC-PC

1227F

1241FAPC

108123266

1260

1360

1227HA

1241CAUC

108123209

1260

1360

FC-PC

1227H

1241FAUC

108123159

OC-12/STM-4 Transmitter Codes

1290

1330

FC-PC

1227AK

1241FBDC

108123456

1290

1330

1227AN

1241CBDC

108123498

1260

1360

FC-PC

1227D

1241FBLC

108123316

1480

1580

1229CA5

1245CBDC

108400391

1480

1580

FC-PC

1229FA5

1245FBDC

108400425

1280

1335

FC-PC

1229FA

1243FBDC

108123506

1280

1335

1229CA

1243CBDC

108123522

1260

1360

FC-PC

1227G

1241FBPC

108123274

1260

1360

FC-PC

1227AC

1241FBUC

108123167

1274

1356

1227PG

1241CBU

108123217

Fibre Channel--1062.5 Mbits/s

1260

1360

FC-PC

1238A

1241FCPC

108309287

1260

1360

FC-PC

1238B

1241FCPD

108309295

1290

1330

FC-PC

1238C

1241FCDC

108309279

Agere Systems Inc. reserves the right to make changes to the product(s) or information contained herein without notice. No liabi lity is assumed as a result of their use or application.

September 1999
DS99-228LWP (Replaces DS99-073LWP)

For additional information, contact your Agere Systems Account Manager or the following:
INTERNET:

http://www.agere.com

E-MAIL:

docmaster@agere.com

N. AMERICA:

Agere Systems Inc., 555 Union Boulevard, Room 30L-15P-BA, Allentown, PA 18109-3286
1-800-372-2447, FAX 610-712-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106)

ASIA:

Agere Systems Hong Kong Ltd., Suites 3201 & 3210-12, 32/F, Tower 2, The Gateway, Harbour City, Kowloon
Tel. (852) 3129-2000, FAX (852) 3129-2020
CHINA: (86) 21-5047-1212 (Shanghai), (86) 10-6522-5566 (Beijing), (86) 755-695-7224 (Shenzhen)
JAPAN: (81) 3-5421-1600 (Tokyo), KOREA: (82) 2-767-1850 (Seoul), SINGAPORE: (65) 778-8833, TAIWAN: (886) 2-2725-5858 (Taipei)

EUROPE:

Tel. (44) 7000 624624, FAX (44) 1344 488 045

Document Outline

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