Data
sheet
2.5 Gb/s Buried Het
Laser 175 km Reach With
Optional Etalon
Stabilisation
This laser module employs the Bookham Technology
strained layer MQW Buried Heterostructure DFB laser chip,
and has been designed specifically for use in Wavelength
Division Multiplexed (WDM) 2.5 Gb/s long distance optical
fibre trunk systems. The device is packaged in a
hermetically sealed 14-pin butterfly package incorporating
an isolator and monitor photodiode for control of the power
of the laser over life and all operating conditions.
The device is available with a number of power options
depending on application and link span requirements.
The optional internal etalon wavelength stabilisation and low chirp
performance makes this product compliant with 50GHz optical
channel spacing.
Features
•
2.5 Gb/s operation
•
+/-95pm wavelength stability over
life without etalon locker
•
Optional etalon wavelength
stabilisation provides 50GHz
optical channel spacing
compliance for interlay
or future upgrade
•
Narrow spectral line-width
•
Internal TEC with precision NTC
thermistor for temperature control
•
Entire C & L-band ITU
wavelengths available
(1527 nm to 1605 nm)
•
Code reduction with single
product for reaches up to 175 km
•
GaInAsP SLMQW DFB single
frequency laser chip
•
InGaAs monitor photo-diode
•
Hermetically sealed 14-pin
butterfly package with
optical isolator
Applications
•
WDM
•
On-off ramps
•
Long-Haul
•
DWDM on ITU Grid
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Parameters
Parameter
Threshold current (Ith)
Slope efficiency by product
2 mW
3 mW
4 mW
10 mW
(1)
1.3
(2)
(3)
-20 dB
32
(4)
Unlocked
Etalon locked
50
40
250
250
0.1
40
125
1200
360
100
10
70°C case temperature
70°C case temperature
20 to 35
Unlocked (5)
Locked, over life & temperature
including chirp (5)
-45
-9
250
600
1.0
0.09
+145
+9
900
2.4
1527
0.04
0.06
0.08
0.143
Conditions
Min
Typ
10
Max
22
0.09
0.13
0.17
0.43
-10
1.8
1605
2
0.6
Unit
mA
mW/mA
RF input reflection coef (S11)
Forward voltage
Peak wavelength (λp)
Dispersion penalty at 175 km
Time averaged spectral linewidth
Side-mode suppression
Optical rise/fall time
Monitor photo current
Monitor dark current
Thermistor resistance
Heatpump current
Heatpump voltage
Change of
λp
with laser temp.
Change in
λ
over life and
operating conditions
Optical Spectral Window
dB
V
nm
dB
nm
dB
ps
µA
nA
kΩ
mA
V
nm/°C
pm
GHz
(1) 50
Ω
measurement system, f = dc - 3 GHz
(2) Submount temperature between 20°C & 35°C start of life to achieve required
λ
p
(3) Standard product dispersion penalty will be compliant to the specified link length of 175 km using an extinction ratio of
10 dB. Fibre dispersion characteristics are derived from the following equation
Where So = 0.092 ps/(nm
2
.km) and
λ
= 1302 nm
(4) Measurements determined from 20 - 80% pk - pk
(5) For more information on wavelength control and drift over life refer to applications note DR1670. To give symmetrical
wavelength performance about the ITU channel wavelength (+/-95pm) offset the laser wavelength by –50pm at start
of life set up
So
λ
D
(
λ
)
=
(
λ −
03
)
ps
/(
nm
.
km
)
4
λ
4
Absolute Maximum Ratings
Parameter
Case operating temperature
Laser submount operating temperature (1)
Storage temperature
Laser current above Ith
Laser reverse voltage
Laser reverse current
Monitor diode bias
Heatpump voltage
Fibre bend radius
30
Min
0
20
-40
Max
70
35
85
100
1.0
10
-10
2.4
Unit
°C
°C
°C
mA
V
µA
V
V
mm
Notes: (1) Product without locker can be tuned onto the next 100 GHz ITU channel in the red shift
direction (2x100 GHz tunability) by increasing the submount temperature to a maximum of 43°C
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Reliability/Quality
Meets Qualification requirements of Telcordia / Bellcore GR468-Core for central office environment.
Operating reliability <500 FITs1 in 15 years.
1- Assumes laser die submount held at <35°C by internal thermoelectric cooler, mean forward current
of 35 mA, and end of life limits based on 10 mA increase in Ith and 25% change in laser efficiency. FIT rate
data for other end of life criteria, including minimum extinction ratio requirements, are available upon request.
Outline Drawing
Dimensions in mm
30
26.04±0.08
20.83
14 PINS x 0.5±0.08
ON 2.54 PITCH
36 MAX
HYTREL SECONDARY COATED
12.7
8.9
DIMENSIONS IN MILLIMETRES
TOLERANCES UNLESS
OTHERWISE SPECIFIED:
X.XX = ±0.25
X.XXX = ±0.127
PIN 1
NOSE CONE BOOT
4 HOLES Ø2.6
MIN
2.79
10.5
12.7
Ø5
MAX
9.92
5.46
1.52
17.8
Figure 1: Outline Drawing
Note: Devices can be supplied with the leads trimmed to a length of 3.81 mm.
Please see Ordering Information section.
Instructions for use – LC25W****A/LC25EW****A
Pin 1 and Pin 2 Thermistor
The thermistor is used in a control loop in conjunction with the thermo-electric cooler to maintain the laser submount
temperature at the required value for wavelength. Operating current should be less than 100 µA to prevent self-heating
errors.
For etalon stabilised devices the thermistor is used for the initial set up of the submount temperature at the required
wavelength value. Operating current should be less than 100 µA to prevent self-heating errors. Once the initial submount
temperature has been achieved control of the TEC current is handed over to the etalon locking circuit to achieve fine tuning.
Pin 3 Laser DC bias (-)
Laser bias current (negative with respect to package ground) is applied via this pin which forms one side of the bias-T
connection to the laser cathode.
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4.12
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Pin 4 Monitor anodes, Pin 5 Common Monitor cathode
The back facet monitor provides a mean power reference for the laser and is normally operated with a 5 V reverse bias.
For etalon stabilised devices the monitor diodes are arranged in the package such that they give an equal monitor current
when the laser wavelength is matched to the ITU grid. A reverse bias must be applied equally across each of the monitors,
this is commonly achieved by applying 5 V to Pin 5.
Pin 6 TEC (+), Pin 7 TEC (-)
Applying a positive voltage on pin 6 with respect to pin 7 will cause the internal submount to be cooled relative to the case
temperature. Reversing the polarity will raise the submount temperature relative to the case. The TEC supply should be
capable of delivering up to 0.9 A at 2.4 V.
Pin 8, 9, 11, 13 Case ground
These pins must be grounded in all applications
Pin 10
This pin is not connected for the LC25W product and it should be grounded if possible. For the Etalon locked product
this pin is used for the monitor long anode. The monitor diodes are arranged such that they give an equal monitor current
when the laser wavelength is matched to the ITU grid. A reverse bias must be applied equally across each of the monitors,
this is commonly achieved by applying 5 V to pin 5.
Pin 12 Laser modulation (-)
The data input (modulation current) is applied via this pin which is a nominal 25 Ohm impedance coplanar line. For 10mW
applications the end of life modulation current is 90mA maximum. For all other applications 60mA maximum modulation
current should be provisioned.
Pin 14 N/C
This pin is not connected. It should be grounded if possible.
Connections
Without Etalon
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Function
Thermistor
Thermistor
Laser DC bias (-)
Monitor Anode (-)
Monitor Cathode (+)
TEC (+)
TEC (-)
Case Ground
Case Ground
Not Connected
Case Ground
Laser Modulation (-)
Case Ground
Not Connected
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
With Etalon
Function
Thermistor
Thermistor
Laser DC bias (-)
Monitor Short Anode (-)
Monitor Cathode (+)
TEC (+)
TEC (-)
Case Ground
Case Ground
Monitor Long Anode (-)
Case Ground
Laser Modulation (-)
Case Ground
Not Connected
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Safety Information
Laser safety classifications:
IEC 60825-1: Edition 1.2 Class 1M
21 CFR Ch.1 (4-1-97 Edition) Class IIIb
Electrostatic discharge:
ESD threshold >500 V
TA-TSY-000870 class 3.
North America
Bookham Technology Inc.
49 Buford Highway
Suwanee
GA 30024
USA
• Tel: +1 678 482 4021
Ordering Information
LC25
[Etalon Option] [Wavelength] [Power Option]
W
= none
EW
= Etalon
****
E
= 2 mWpk
C
= 3 mWpk
A
= 4 mWpk
B
= 10 mWpk
[Reach]
A
= 175 km -
[Connector]
C28
= SC/PC
C34
= FC/PC
C57
= LC
C59
= MU
• Fax: +1 678 482 4022
Europe
Bookham Technology plc
Brixham Road
Paignton
Devon
TQ4 7BE
UK
• Tel: +44 (0) 1803 66 2875
• Fax: +44 (0) 1803 66 2801
**** = Last four digits of wavelength value E.g. for
λp
= 1545.32 nm **** = 4532
Product without locker can be tuned onto the next 100 GHz ITU channel in the red
shift direction (2x100 GHz tunability) i.e. an LC25W4135CA-C28 can be tuned to
service the 1542.14 nm ITU channel.
Fibre length 1130 to 1190 mm
Other connector types are available on request.
E.g.
LC25W4532BA-C28
is a 10 mW 1545.32 nm device with an SC connector
for use in a 175 km application.
E.g.
LC25EW4532EA-C28
is a 2 mW 1545.32 nm device with an SC connector
for use in a 175 km application with optional etalon stabilisation.
Asia
Bookham Technology plc
21/F Cityplaza One
1111 King's Road
Quarry Bay
Hong Kong
• Tel: +852 (2100) 2249
• Fax: +852 (2100) 2585
Sales@bookham.com
Trimmed lead option
Devices can be supplied with the leads trimmed to a length of 3.81 mm typ.
This option can be specified by adding a ‘K’ suffix after the reach option.
E.g. LC25W4532BAK-C28 is a 10 mW 1545.32 nm device with an SC connector
and a lead length of 3.81 mm typical, for use in a 175 km application.
Important Notice
Bookham Technology has a policy of
continuous improvement, as a result
certain parameters detailed on this flyer
may be subject to change without notice.
If you are interested in a particular product
please request the available from any
Bookham Technology sales representative.
INVISIBLE LASER RADIATION
DO NOT VIEW DIRECTLY
WITH OPTICAL INSTRUMENTS
CLASS 1M LASER
REFERENCE IEC 60825-1: Edition 1.2
DANGER
INVISIBLE LASER RADIATION
AVOID DIRECT
EXPOSURE TO BEAM
OUTPUT POWER 21 mW
WAVELENGTH >1510 nm
CLASS IIIb LASER PRODUCT
THIS PRODUCT COMPLIES WITH 21 CFR 1040.10
CAUTION
STATIC SENSITIVE DEVICE
OBSERVE PRECAUTIONS
Certificate No. FM 15040
Certificate No. EMS 35100
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REV 1 Feb 2003
© Bookham Technology 2003 Bookham & ASOC are registered trademarks of Bookham Technology plc
Analogue and Mixed Signal
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