Data Sheet
August 2000
D2570, D2526, D2555 Wavelength-Selected
Direct Modulated Isolated DFB Laser Module
Applications
s
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
Product
Code
The 1.5
µ
m D2570, D2526G, and D2555 Laser Modules are
available in a 14-pin, hermetic, butterfly package.
Peak
Power
10 mW
2 mW
2 mW
Dispersion
Performance
1800 ps/nm (100 km)
1800 ps/nm (100 km)
3000 ps/nm (170 km)
D2570H
D2526G
D2555G
Features
s
Description
The Direct Modulated Isolated DFB Laser Module
contains an internally cooled, InGaAs, MQW, distrib-
uted-feedback (DFB) laser designed for 1.5
µ
m appli-
cations. The following three direct-modulation DWDM
product families have been established to meet vari-
ous OC-48/STM-16 system applications:
s
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
s
s
s
s
s
s
s
s
s
s
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.
s
s
s
*
Telcordia Technologies
is a trademark of Bell Communications
Research, Inc.
D2570, D2526G, D2555 Wavelength-Selected
Direct Modulated Isolated DFB Laser Module
Data Sheet
August 2000
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.
Pin Information
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Name
Thermistor
Thermistor
Laser dc Bias (Cathode) (–)
Back-facet Monitor Anode (–)
Back-facet Monitor Cathode (+)
Thermoelectric Cooler (+)
†
Thermoelectric Cooler (–)
‡
Case Ground
Case Ground
Case Ground
Laser Anode (+)
‡
RF Laser Input Cathode (–)
Laser Anode (+)
‡
Case Ground
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.
† A positive current through the thermoelectric heat pump cools the
laser.
‡ Both leads should be grounded for optimum performance.
7
–
6
+
5
+
4
–
L1
160 nH
3
–
2
1
TH
10 kΩ
TEC
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 Corning SMF-28
type fiber. The fiber has a 900
µ
m tight buffer jacket.
Various connectors and pigtail lengths are available.
Lucent Technologies Microelectronics Group’s opto-
electronic components are being qualified to rigorous
internal standards that are consistent with
Telcordia
Technologies
TR-NWT-000468. All design and manu-
facturing operations are
ISO
* 9001 certified. The mod-
ule is being fully qualified for central office applications.
8
PACKAGE
GROUNDS
+
9
10
11
R1
20
Ω
–
12
ISOLATOR
+
13
14
1-567
Top view.
Figure 1. Circuit Schematic
*
ISO
is a registered trademark of The International Organization for
Standardization.
2
Lucent Technologies Inc.
Data Sheet
August 2000
D2570, D2526G, D2555 Wavelength-Selected
Direct Modulated Isolated DFB Laser Module
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.
Parameter
Laser Reverse Voltage
dc Forward Current
Operating Case Temperature Range
Storage Case Temperature Range*
Photodiode Reverse Voltage
Photodiode Forward Current
* Does not apply to shipping container.
Symbol
V
RLMAX
I
FLMAX
T
C
T
stg
V
RPDMAX
I
FPDMAX
Min
—
—
–40
–40
—
—
Max
2
150
70
85
10
2
Unit
V
mA
°
C
°
C
V
mA
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.
Mounting Instructions
The minimum fiber bend radius is 30 mm (1.18 in).
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
µ
in. (0.8
µ
m), and the surface flat-
ness must be better than 0.001 in. (25.4
µ
m). Using
thermal conductive grease is optional; however,
thermal performance can be improved by up to 5% if
conductive 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.
0.062 (1.58)
0.031 (0.79)
0.140
(3.56)
0.129 (3.28) R
0.041 (1.04)
Note: Dimensions are in inches and (millimeters).
1-532
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).
0.118
(3.00)
0.086
(2.18)
Lucent 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 k
Ω
, capacitance = 100 pF) is widely
used and, therefore, can be used for comparison pur-
poses. The HBM ESD threshold presented here was
obtained using these circuit parameters:
Parameter
Human-body Model
Lucent Technologies Inc.
Value
>400
Unit
V
Figure 2. Fillister Head Screw
3
D2570, D2526G, D2555 Wavelength-Selected
Direct Modulated Isolated DFB Laser Module
Data Sheet
August 2000
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.
Table 1. Electrical Characteristics (at 25
°
C laser temperature)
Parameter
Slope Efficiency
Threshold Current
Laser Forward Voltage
Monitor Reverse-bias Voltage*
Monitor Current
Monitor Dark Current
Input Impedance
Thermistor Current
Resistance Ratio
†
Thermistor Resistance
TEC Current
TEC Voltage
TEC Capacity
Symbol
η
I
TH
V
LF
V
RMON
I
RMON
I
D
Z
IN
I
TC
—
R
TH
I
TEC
V
TEC
∆
T
Test Conditions
L
F
= 2 mW (CW)
—
L
F
= 2 mW (CW)
—
P
OL
= 1 mW (CW)
I
F
= 0, V
RMON
= 5 V
—
—
—
T
L
= 25
°
C
T
L
= 25
°
C, T
C
= 70
°
C
T
L
= 25
°
C, T
C
= 70
°
C
T
C
= 70
°
C
Min
0.06
—
—
3
0.1
—
—
10
9.1
9.5
—
—
50
Typ
0.09
14
1.3
5
1.0
0.01
25
—
—
—
0.6
1.3
—
Max
0.13
25
1.8
10
1.5
0.1
—
100
9.6
10.5
1.0
2.0
—
Unit
mW/mA
mA
V
V
mA
µ
A
Ω
µ
A
—
k
Ω
A
V
°
C
* Standard operating condition is 5.0 V reverse bias.
† Ratio of thermistor resistance at 0
°
C to thermistor resistance at 50
°
C.
Table 2. Optical Characteristics (at 25
°
C laser temperature)
Parameter
Peak Optical Output Power
Center Wavelength
(See Table 10.)
Spectral Width:
Full Width at –3 dB
Full Width at –20 dB
Side-mode Suppression Ratio
Optical Isolation
Center Wavelength Drift with
Case Temperature
Wavelength Temperature Tuning
Coefficient
Table 3. Dispersion Performance
Parameter
Dispersion Penalty for Extended Reach
Symbol
DP
Test
Conditions
1800 ps/nm
Min
—
Typ
—
Max
2.0
Unit
dB
Symbol
P
PEAK
λc
∆λ
Test Conditions
—
T
L
= 25
°C
CW wavelength
Modulated at 2.5 Gbits/s
at rated power
CW
T
C
= 0
°C
to 70
°C
0
°C ≤
T
C
≤
70
°C
—
Min
2.0
1528.77
Typ
—
—
Max
—
1610.06
Unit
mW
nm
SMSR
—
∆λ
C
/∆T
C
—
—
—
30
30
—
—
0.1
0.3
—
—
—
0.09
0.30
1.0
—
—
1
—
nm
nm
dB
dB
pm/°C
nm/°C
4
Lucent Technologies Inc.
Data Sheet
August 2000
D2570, D2526G, D2555 Wavelength-Selected
Direct Modulated Isolated DFB Laser Module
D2555 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 test-
ing requirements.
Table 4. Electrical Characteristics (at 25
°C
laser temperature)
Parameter
Slope Efficiency
Threshold Current
Laser Forward Voltage
Monitor Reverse-bias Voltage*
Monitor Current
Monitor Dark Current
Input Impedance
Thermistor Current
Resistance Ratio
†
Thermistor Resistance
TEC Current
TEC Voltage
TEC Capacity
Symbol
η
I
TH
V
LF
V
RMON
I
RMON
I
D
Z
IN
I
TC
—
R
TH
I
TEC
V
TEC
∆T
Test Conditions
L
F
= 2 mW (CW)
—
L
F
= 2 mW (CW)
—
P
OL
= 1 mW (CW)
I
F
= 0, V
RMON
= 5 V
—
—
—
T
L
= 25
°C
T
L
= 25
°C,
T
C
= 70
°C
T
L
= 25
°C,
T
C
= 70°C
T
C
= 70
°C
Min
0.05
—
—
3
0.1
—
—
10
9.1
9.5
—
—
50
Typ
0.08
12
1.3
5
1.0
0.01
25
—
—
—
0.6
1.3
—
Max
0.10
35
1.8
10
1.9
0.1
—
100
9.6
10.5
1.0
2.0
—
Unit
mW/mA
mA
V
V
mA
µA
Ω
µA
—
kΩ
A
V
°C
* Standard operating condition is 5.0 V reverse bias.
† Ratio of thermistor resistance at 0
°C
to thermistor resistance at 50
°C.
Table 5. Optical Characteristics (at 25
°C
laser temperature)
Parameter
Peak Optical Output Power
Center Wavelength
(See Table 11.)
Spectral Width:
Full Width at –3 dB
Full Width at –20 dB
Side-mode Suppression Ratio
Optical Isolation
Center Wavelength Drift with
Case Temperature
Wavelength Temperature Tuning
Coefficient
Table 6. Dispersion Performance
Parameter
Dispersion Penalty for Extended Reach
Symbol
DP
Test
Conditions
3000 ps/nm
Min
—
Typ
—
Max
2.0
Unit
dB
Symbol
P
PEAK
λc
∆λ
Test Conditions
—
T
L
= 25
°C
CW wavelength
Modulated at 2.5 Gbits/s
at rated power
CW
T
C
= 0
°C
to 75
°C
0
°C ≤
T
C
≤
75
°C
—
Min
2.0
1528.77
Typ
—
—
Max
—
1563.86
Unit
mW
nm
SMSR
—
∆λ
C
/∆T
C
—
—
—
30
30
—
—
0.1
0.3
—
—
—
0.09
0.30
1.0
—
—
1
—
nm
nm
dB
dB
pm/°C
nm/°C
Lucent Technologies Inc.
5
电源技术
