D2570, D2526, D2555 Wavelength-Selected
Direct Modulated Isolated DFB Laser Module

Data Sheet, Rev. 3

July 2001

The 1.5

m 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 elimi-
nate the need for external wavelength locker

Qualified to meet the intent of

Telcordia Technolo-

gies

* 468

Telcordia Technologies

is a trademark of Telcordia Technologies,

Inc.

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

Product Codes

Description

The Direct Modulated Isolated DFB Laser Module
contains an internally cooled, InGaAs, MQW, distrib-
uted-feedback (DFB) laser designed for 1.5

m appli-

cations. The following three direct-modulation DWDM
product families have been established to meet vari-
ous 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-performance device designed for
very low dispersion; used in fiber spans exceeding
170 km (3000 ps/nm).

D2570-type: high-power, direct-modulated laser
eliminates the need for optical amplifiers in DWDM
many applications.

Product

Code

Peak

Power

Dispersion

Performance

D2570H

10 mW

1800 ps/nm (100 km)

D2526G

2 mW

1800 ps/nm (100 km)

D2555G

2 mW

3000 ps/nm (170 km)

Agere Systems Inc.

D2570, D2526G, D2555 Wavelength-Selected

Data Sheet, Rev. 3

Direct Modulated Isolated DFB Laser Module

July 2001

Description

(continued)

Controlled Feedback

The module contains an internal optical isolator that
suppresses optical feedback in laser-based, fiber-optic
systems. Light reflected back to the laser is attenuated
a minimum of 30 dB.

Controlled Temperature

An integral thermoelectric cooler (TEC) provides stable
thermal characteristics. The TEC allows for heating
and cooling of the laser chip to maintain a temperature
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 with external circuitry to
control the laser chip temperature.

Controlled Power

An internal, InGaAs, PIN photodiode functions as the
back-facet monitor. The photodiode monitors emission
from the rear facet of the laser and, when used in con-
junction with control circuitry, can control optical power
launched into the fiber. Normally, this configuration is
used in a feedback arrangement 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

impedance.

The laser module is equipped with

SMF-28

type fiber.

The fiber has a 900 µm tight buffer jacket. Various con-
nectors and pigtail lengths are available.

Agere Systems' optoelectronic components are being
qualified to rigorous internal standards that are consis-
tent with

Telcordia Technologies

TR-NWT-000468. All

design and manufacturing operations are

ISO

* 9001

certified. The module is being fully qualified for central
office applications.

ISO

is a registered trademark of The International Organization for

Standardization.

SMF-28

is a trademark of Corning Inc.

Pin Information

* A positive current through the thermoelectric heat pump cools the

laser.

Both leads should be grounded for optimum performance.

Top view.

Figure 1. Circuit Schematic

Pin

Name

Thermistor

Laser dc Bias (Cathode) ()

Back-facet Monitor Anode ()

Back-facet Monitor Cathode (+)

Thermoelectric Cooler (+)*

Thermoelectric Cooler ()

Case Ground

Laser Anode (+)

RF Laser Input Cathode ()

Laser Anode (+)

Case Ground

1-567F.b

TEC

160 nH

ISOLATOR

R1
20

PACKAGE

GROUNDS

10 k

Data Sheet, Rev. 3

D2570, D2526G, D2555 Wavelength-Selected

July 2001

Direct Modulated Isolated DFB Laser Module

Agere Systems Inc.

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 performance characteristics of the data sheet. Exposure to absolute maximum ratings for
extended periods can adversely affect device reliability.

* Does not apply to shipping container.

Parameter

Symbol

Min

Max

Unit

Laser Reverse Voltage

RLMAX

dc Forward Current

FLMAX

150

Operating Case Temperature Range

°C

Storage Case Temperature Range*

stg

°C

Photodiode Reverse Voltage

RPDMAX

Photodiode Forward Current

FPDMAX

Handling Precautions

Power Sequencing

To avoid the possibility of damage to the laser module
from power supply switching transients, follow this turn-
on 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 guide-
lines such as JEDEC Publication No.
108-A (Dec. 1988).

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 pre-
sented here was obtained using these circuit parame-
ters:

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 surface flatness
must be better than 0.001 in. (25.4 µm). Using ther-
mal conductive grease is optional; however, thermal
performance can be improved by up to 5% if con-
ductive grease is applied between 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.

Figure 2. Fillister Head Screw

Parameter

Value

Unit

Human-body Model

>400

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)

Agere Systems Inc.

D2570, D2526G, D2555 Wavelength-Selected

Data Sheet, Rev. 3

Direct Modulated Isolated DFB Laser Module

July 2001

D2526 Characteristics

Minimum and maximum values are testing requirements. Typical values are characteristics of the device and are
the result of engineering evaluations. Typical values are for information purposes only and are not part of the testing
requirements.

* Standard operating condition is 5.0 V reverse bias.
Ratio of thermistor resistance at 0 °C to thermistor resistance at 50 °C.

Table 1. Electrical Characteristics (at 25 °C laser temperature)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

Slope Efficiency

= 2 mW (CW)

0.06

0.09

0.13

mW/mA

Threshold Current

Laser Forward Voltage

= 2 mW (CW)

1.3

1.8

Laser Submount Temperature

LASER

°C

Monitor Reverse-bias Voltage*

RMON

Monitor Current

RMON

= 1 mW (CW)

0.1

0.3

1.5

Monitor Dark Current

= 0, V

RMON

= 5 V

0.01

0.1

Input Impedance

Thermistor Current

100

Resistance Ratio

9.1

9.6

Thermistor Resistance

= 25 °C

9.5

10.5

TEC Current

TEC

= 25 °C, T

= 70 °C

0.6

1.0

TEC Voltage

TEC

= 25 °C, T

= 70°C

1.3

2.0

TEC Capacity

= 70 °C

°C

Table 2. Optical Characteristics (at 25 °C laser temperature)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

Peak Optical Output Power

PEAK

2.0

Center Wavelength

(See Table 10.)

= 25 °C

CW wavelength

1528.77

1610.06

Line Width (3 dB full width)

Modulated at 2.5 Gbits/s

at rated power

MHz

Side-mode Suppression Ratio

SMSR

Optical Isolation

= 0 °C to 70 °C

Wavelength Drift (EOL)

Tested over

25-year lifetime

±0.1

Center Wavelength Drift with

Case Temperature

0 °C

70 °C

pm/°C

Wavelength Temperature Tuning

Coefficient

0.095

nm/°C

Tracking Error

= 20 °C/25 °C/70 °C

Table 3. Dispersion Performance

Parameter

Symbol

Test

Conditions

Min

Typ

Max

Unit

Dispersion Penalty for Extended Reach

1800 ps/nm

2.0

Data Sheet, Rev. 3

D2570, D2526G, D2555 Wavelength-Selected

July 2001

Direct Modulated Isolated DFB Laser Module

Agere Systems Inc.

D2555 Characteristics

* Standard operating condition is 5.0 V reverse bias.
Ratio of thermistor resistance at 0 °C to thermistor resistance at 50 °C.

Table 4. Electrical Characteristics (at 25 °C laser temperature)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

Slope Efficiency

= 2 mW (CW)

0.05

0.08

0.10

mW/mA

Threshold Current

Laser Forward Voltage

= 2 mW (CW)

1.3

1.8

Laser Submount Temperature

LASER

°C

Monitor Reverse-bias Voltage*

RMON

Monitor Current

RMON

= 1 mW (CW)

0.1

0.3

1.9

Monitor Dark Current

= 0, V

RMON

= 5 V

0.01

0.1

Input Impedance

Thermistor Current

100

µA

Resistance Ratio

9.1

9.6

Thermistor Resistance

= 25 °C

9.5

10.5

TEC Current

TEC

= 25 °C, T

= 70 °C

0.6

1.0

TEC Voltage

TEC

= 25 °C, T

= 70°C

1.3

2.0

TEC Capacity

= 70 °C

°C

Table 5. Optical Characteristics (at 25 °C laser temperature)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

Peak Optical Output Power

PEAK

2.0

Center Wavelength

(See Table 11.)

= 25 °C

CW wavelength

1528.77

1563.86

Line Width (3 dB full width)

Modulated at 2.5 Gbits/s

at rated power

MHz

Side-mode Suppression Ratio

SMSR

Optical Isolation

= 0 °C to 75 °C

Wavelength Drift (EOL)

Tested over

25-year lifetime

±0.1

Center Wavelength Drift with

Case Temperature

0 °C

75 °C

pm/°C

Wavelength Temperature Tuning

Coefficient

0.095

nm/°C

Tracking Error

= 20 °C/25 °C/70 °C

Table 6. Dispersion Performance

Parameter

Symbol

Test

Conditions

Min

Typ

Max

Unit

Dispersion Penalty for Extended Reach

3000 ps/nm

2.0

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