D2570, D2526, D2555 Wa velength-Selected
Direct Modulated Isolated DFB Laser Module
Data Sheet, Rev. 3
July 2001
Applications
■
Three direct-modulated DWDM families available
to meet a number of OC-48/STM-16 applications:
—Extended reach (100 km)
—Very long reach (170 km)
—Metro DWDM
—Digital video
The 1.5 µm D2570, D2526G, and D2555 Laser Modules are
available in a 14-pin, hermetic, butterfly package.
Features
■
ITU wavelengths available from
1528.77 nm —1610.06 nm
■
SONET/SDH compatible up to OC-48/STM-16
■
Temperature tunable for precise wavelength
selection
■
Integrated optical isolator
■
High-performance, multiquantum well (MQW)
distributed-feedback (DFB) laser
■
Industry-standard, 14-pin butterfly package
■
Characterized at 2.488 Gbits/s (NRZ)
■
InGaAs, PIN photodetector back-facet monitor
■
Low threshold current
■
High-reliability, hermetic packaging
■
Excellent long-term wavelength stability can eliminate the need for external wavelength locker
■
Qualified to meet the intent of
gies
* 468
*
Telcordia Technologies
Inc.
is a trademark of Telcordia Technologies,
Telcordia Technolo-
Product Codes
Product
Code
D2570H10 mW1800 ps/nm (100 km)
D2526G2 mW1800 ps/nm (100 km)
D2555G2 mW3000 ps/nm (170 km)
Peak
Power
Dispersion
Performance
Description
The Direct Modulated Isolated DFB Laser Module
contains an internally cooled, InGaAs, MQW, distributed-feedback (DFB) laser designed for 1.5 µm applications. The f ollowing three d irect-modulation D WDM
product families have been established to meet various OC-48/STM-16 system applications:
■
D2526-type: designed to be used in OC-48/
STM-16 (2.488 Gbits/s) for extended reach, dense
WDM applications (1800 ps/nm). The wavelength
of the laser can be temperature-tuned for precise
wavelength selection by adjusting the temperature
of the internal thermoelectric cooler.
■
D2555-type: high-perf ormance device designe d for
very low dispersion; used in fi ber sp ans exceeding
170 km (3000 ps/nm).
■
D2570-type: high-power, direct-modulated laser
eliminates the need for optic al amplifier s in DWDM
many applications.
D2570, D2526G, D2555 Wavelength-Selected Data Sheet, Rev. 3
Direct Modulated Isolated DFB Laser ModuleJuly 2001
Description
(continued)
Controlled Feedback
The module contains an internal optical isolator that
suppresses optical fee dbac k in l aser-based, fi ber-opt ic
systems. Light reflected back to the laser is attenuated
a minimum of 30 dB.
Controlled Temperature
An integral thermoelectric cooler (TEC) provides stab le
thermal characteristics. The TEC allows for heating
and cooling of the laser chip to mai ntain a te mper ature
of 25 °C for case temperatures from –40 °C to +70 °C .
The laser temperature is monitored by the internal
thermistor, which can be used wi th external circuitry to
control the laser chip temperature.
Controlled Power
An internal, InGaAs, PIN photodiode functions as the
back-f a ce t moni tor. The photodiode monitors emission
from the rear facet of the laser and, when used in conjunction with control circuitry, can control optical power
launched into the fiber. Normally, this configuration is
used in a feedback arr angement to maintain consistent
laser output power.
Standard Package
The laser module is fabricated in a 14-pin, hermetic,
metal/ceramic butterfly package that incorporates a
bias tee, which separates the dc-bias path from the RF
input. The RF input has a nominal 25 Ω impedance.
The laser module is equipped with
SMF-28
The fiber has a 900 µm tight buffer jacket. Var ious connectors and pigtail lengths are available.
* A positive current through the thermoelectric heat pump cools the
laser.
† Both leads should be grounded for optim um performance.
76 54 32 1
++– –
–
TEC
PACKAGE
GROUNDS
8910111213
Top view.
160 nH
+–+
L1
R1
20
Ω
TH
10 k
Ω
ISOLATOR
NC
14
Figure 1. Circuit Schematic
†
†
†
1-567F.b
Agere Systems’ optoelectronic components are being
qualified to rigorous internal standards that are consistent with
design and manufacturing operations are
Telcordia Technologies
TR-NWT-000468. All
ISO
* 9001
certified. The module is being fully qualified for central
office applications.
*
ISO
is a registered trademark of The International Organization f or
Standardization.
†
SMF-28
is a trademark of Corning Inc.
2Agere Systems Inc.
Data Sheet, Rev . 3D2570, D2526G, D2555 Wavelength-Selected
1-532
Note: Dimensions are in inches and (millimeters).
0.118
(3.00)
0.062 (1.58)
0.140
(3.56)
0.031 (0.79)
0.129 (3.28) R
0.086
(2.18)
0.041 (1.04)
July 2001Direct Modulated Isolated DFB Laser Module
Absolute Maximum Rat ings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are absolute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the performance characteristics of the data sheet. Exposure to absolute maximum ratings for
extended periods can adversely affect device reliability.
ParameterSymbolMinMaxUnit
Laser Reverse VoltageV
dc Forward CurrentI
Operating Case Temperature RangeT
Storage Case Temperature Range*T
Photodiode Reverse VoltageV
Photodiode Forward CurrentI
* Does not apply to shipping container.
RLMAX
FLMAX
C
stg
RPDMAX
FPDMAX
—2V
—150mA
–4070°C
–4085°C
—10V
—2mA
Handling Precautions
Power Sequencing
To avoid the possibility of damage to the laser module
from power supply switching transients, follow this turnon sequence:
1. All ground connections
2. Most negative supply
3. Most positive supply
4. All remaining connections
Reverse the order for the proper turn-off sequence.
Electrostatic Discharge
CAUTION: This device is susceptible to damage
as a result of electrostatic discharge.
Take proper precautions during both
handling and testing. Follow guidelines such as JEDEC Publication No.
108-A (Dec. 1988).
Mounting Instructions
The minimum fiber bend radius is 1.23 in (31.25 mm).
To avoid degradation in performance, mount the mod-
ule on the board as follows:
1. Place the bottom flange of the module on a flat heat
sink at least 0.5 in. x 1.180 in. (12.7 mm x 30 mm) in
size. The surface finish of the heat sink should be
better than 32 µin. (0.8 µm), and the surf ace flatness
must be better than 0.001 in. (25.4 µm). Using thermal conductive grease is optional ; how ever, thermal
performance can be improved by up to 5% if conductive grease is app lied betwe en the bottom flange
and the heat sink.
2. Mount four #2-56 screws with Fillister heads
(M2-3 mm) at the four screw hole locations (see
Outline Diagram). The Fillister head diameter must
not exceed 0.140 in. (3.55 mm). Do not apply more
than 1 in./lb. of torque to the screws.
Agere Systems employs a human-body model (HBM)
for ESD-susceptibility testing and protection-design
evaluation. ESD voltage thresholds are dependent on
the critical parameters used to define the model. A
standard HBM (resistance = 1.5 k¾, capacitance =
100 pF) is widely used and, therefore, can be used for
comparison purposes. The HBM ESD threshold presented here was obtained using these circuit parameters:
ParameterValueUnit
Human-body Model>400V
Agere Systems Inc.3
Figure 2. Fillister Head Screw
D2570, D2526G, D2555 Wavelength-Selected Data Sheet, Rev. 3
Direct Modulated Isolated DFB Laser ModuleJuly 2001
D2526 Characteristics
Minimum and maximum values are testing requirements. Typical values are characteristics of the device and are
the result of engineering e v aluations . Typical values are for inf ormation purposes only and are not part of the testing
requirements.
Table 1. Electrical Characteristics (at 25 °C laser temperature)