Data
sheet
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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
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.
Parameter
Min
Max
Unit
Case operating temperature
0
70
C
Laser submount operating temperature (1)
20
35
C
Storage temperature
-40
85
C
Laser current above Ith
100
mA
Laser reverse voltage
1.0
V
Laser reverse current
10
A
Monitor diode bias
-10
V
Heatpump voltage
2.4
V
Fibre bend radius
30
mm
Parameter
Conditions
Min
Typ
Max
Unit
Threshold current (Ith)
10
22
mA
Slope efficiency by product
2 mW
0.04
0.09
3 mW
0.06
0.13
mW/mA
4 mW
0.08
0.17
10 mW
0.143
0.43
RF input reflection coef (S11)
(1)
-10
dB
Forward voltage
1.3
1.8
V
Peak wavelength (
p)
(2)
1527
1605
nm
Dispersion penalty at 175 km
(3)
2
dB
Time averaged spectral linewidth
-20 dB
0.1
0.6
nm
Side-mode suppression
32
40
dB
Optical rise/fall time
(4)
125
ps
Monitor photo current
Unlocked
50
250
1200
A
Etalon locked
40
250
360
Monitor dark current
100
nA
Thermistor resistance
10
k
Heatpump current
70C case temperature
250
600
900
mA
Heatpump voltage
70C case temperature
1.0
2.4
V
Change of
p with laser temp.
20 to 35
0.09
nm/C
Change in
over life and
Unlocked (5)
-45
+145
pm
operating conditions
Optical Spectral Window
Locked, over life & temperature
-9
+9
GHz
including chirp (5)
Parameters
(1)
50
measurement system, f = dc - 3 GHz
(2)
Submount temperature between 20C & 35C start of life to achieve required
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
= 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
)
.
/(
)
(
4
)
(
3
4
0
km
nm
ps
So
D
-
=
Absolute Maximum Ratings
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 43C
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Outline Drawing
Dimensions in mm
PIN 1
1.52
30
26.040.08
20.83
14 PINS x 0.50.08
8.9
12.7
12.7
MIN
2.79
ON 2.54 PITCH
17.8
10.5
5
9.92
4.12
4 HOLES 2.6
36 MAX
NOSE CONE BOOT
HYTREL SECONDARY COATED
DIMENSIONS IN MILLIMETRES
TOLERANCES UNLESS
OTHERWISE SPECIFIED:
X.XX = 0.25
X.XXX = 0.127
MAX
5.46
Figure 1: Outline Drawing
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 <35C 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.
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 A 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 A 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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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.
Without Etalon
With Etalon
Pin Function
Pin
Function
1
Thermistor
1
Thermistor
2
Thermistor
2
Thermistor
3
Laser DC bias (-)
3
Laser DC bias (-)
4
Monitor Anode (-)
4
Monitor Short Anode (-)
5
Monitor Cathode (+)
5
Monitor Cathode (+)
6
TEC (+)
6
TEC (+)
7
TEC (-)
7
TEC (-)
8
Case Ground
8
Case Ground
9
Case Ground
9
Case Ground
10
Not Connected
10
Monitor Long Anode (-)
11
Case Ground
11
Case Ground
12
Laser Modulation (-)
12
Laser Modulation (-)
13
Case Ground
13
Case Ground
14
Not Connected
14
Not Connected
Connections
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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.
Ordering Information
LC25
[Etalon Option] [Wavelength] [Power Option]
[Reach]
[Connector]
W = none
****
E = 2 mWpk
A = 175 km -
C28 = SC/PC
EW = Etalon
C = 3 mWpk
C34 = FC/PC
A = 4 mWpk
C57 = LC
B = 10 mWpk
C59 = MU
**** = Last four digits of wavelength value E.g. for
p = 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.
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.
THIS PRODUCT COMPLIES WITH 21 CFR 1040.10
INVISIBLE LASER RADIATION
DO NOT VIEW DIRECTLY
WITH OPTICAL INSTRUMENTS
CLASS 1M LASER
DANGER
INVISIBLE LASER RADIATION
AVOID DIRECT
EXPOSURE TO BEAM
OUTPUT POWER 21 mW
WAVELENGTH >1510 nm
CLASS IIIb LASER PRODUCT
CAUTION
STATIC SENSITIVE DEVICE
OBSERVE PRECAUTIONS
Certificate No. FM 15040
Certificate No. EMS 35100
REFERENCE IEC 60825-1: Edition 1.2
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REV 1 Feb 2003
Bookham Technology 2003 Bookham & ASOC are registered trademarks of Bookham Technology plc
North America
Bookham Technology Inc.
49 Buford Highway
Suwanee
GA 30024
USA
Tel: +1 678 482 4021
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
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
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.
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