Data
sheet
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Thinking optical solutions
2.5 Gb/s Buried Het
4x100GHz Tunable Laser
with Etalon Stabilisation
and extended reach
option
This laser module employs the Bookham Technology gain
coupled SLMQW 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 locking optics to lock
and stabilise wavelength and power of the laser over life.
The module is tunable by means of the internal thermo-electric
cooler over four adjacent 100 GHz ITU WDM channels.
The device is available with a number of power options
and wavelength schemes which are customizable to individual
customer specification. The internal etalon wavelength
stabilisation and low chirp performance makes this product
compliant with 50GHz optical channel spacing.
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Features
2.5 Gb/s Operation
Tunable over four separate
channels at 100 GHz
channel spacing
Integrated wavelength
locking optics
Entire C band ITU wavelengths
available (1528 to 1563 nm)
Narrow spectral line-width
Hermetically sealed 14 pin
butterfly package with
optical isolator
Internal TEC with precision
NTC thermistor
Extended reach performance
up to 360 km with low
dispersion penalty
50GHz optical channel spacing
compliant for interlay or future
upgrade
Applications
Optical Service Channel (OSC)
applications in DWDM
transmission systems using
optical amplifiers.
Figure 1: Schematic diagram
Parameter
Conditions
Min
Typ
Max
Unit
Threshold current (Ith)
10
22
mA
Slope efficiency
2 mW
0.04
0.09
mW/mA
3 mW
0.06
0.13
mW/mA
4 mW
0.08
0.17
mW/mA
High Power (1)
0.143
0.43
mW/mA
RF input reflection coef (S11)
(2)
-10
dB
Forward voltage
1.3
1.8
V
Peak wavelength (
p)
(3)
1527
1563
nm
Dispersion penalty
(4)
2
dB
Time averaged spectral linewidth
-20dB
0.4
0.6
nm
Side-mode suppression
34
40
dB
Optical rise/fall time
(5)
125
ps
Monitor photo currents
40
250
360
A
Monitor dark current
50
nA
Thermistor resistance
4.07
20.7
k
Heatpump current
T = 64C
1000
mA
Heatpump voltage
T = 64C
2.4
V
Change of
with laser temp.
8 to 50C
0.09
nm/C
Optical Spectral Window
Over life & temperature
-9
+9
GHz
including chirp (6)
Parameters
(1) The high power version provides 10 mW peak output power for 175 km applications and 7 mW peak ouput power
for 360 km applications.
(2) 50
measurement system, f = dc - 3 GHz.
(3) Submount temperature between 0C & 40C start of life to achieve required
p.
(4) Dispersion penalty is compliant to a link length of 175 km or 360 km using an extinction ratio of 10dB.
Fibre dispersion characteristics are derived from the following equation:
where So =0.092 ps/(nm
2
km) and
0
= 1302 nm.
(5) Measurements determined from 20 - 80% Pk - Pk
(6) For more information on wavelength control over life refer to application note DR1670
)
.
/(
)
(
4
)
(
3
4
0
km
nm
ps
So
D
-
=
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Reliability/Quality
Meets Qualification requirements of Telcordia / Bellcore GR468-Core for central office environment. Operating reliability <500
FITs
1
in 15 years.
1 - Assumes laser die submount is held within the range 8C to 50C by the internal thermoelectric cooler and the product is
deployed in equal quantities on each of the four channels with a mean forward current of 35 mA. 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.
Parameter
Min
Max
Units
Case operating temperature
0
+70
C
Laser submount operating temperature
8
50
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
Heat Pump Current
1
A
Heatpump voltage
2.4
V
Fibre bend radius
30
mm
Absolute Maximum Ratings
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 2: Outline Drawing and Pinout Information
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Pin #
Function
Pin #
Function
1
Thermistor
8
Case ground
2
Thermistor
9
Case ground
3
Laser DC bias (-)
10
Monitor long anode (-)
4
Monitor short anode (-)
11
Laser case ground
5
Monitor cathode (+)
12
Laser modulation (-)
6
TEC (+)
13
Laser case ground
7
TEC(-)
14
N/C
Connections
Instructions for use LC25ET
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. Operating current should be less than 100
A to prevent self-heating errors.
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.
Pin 4 + 10 Monitor anodes, Pin 5 Common Monitor cathode
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 10 V to Pin 5.
Pin 6 TEC (+), Pin 7 TEC (-)
Applying a positive voltage on pin 6 with respect to pin 7 causes the internal submount to be cooled relative to the case
temperature. Reversing the polarity raises the submount temperature relative to the case. The TEC supply is capable
of delivering up to 1.0 A at 2.4 V.
Pin 8, 9, 11, 13 Case ground
These pins must be grounded in all applications.
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. Ground it, if possible.
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REFERENCE IEC 608251: Edition 1.2
INVISIBLE LASER RADIATION
DO NOT VIEW DIRECTLY
WITH OPTICAL
INSTRUMENTS
CLASS 1M LASER
Certificate No. FM 15040
Certificate No. EMS 35100
CAUTION
STATIC SENSITIVE DEVICE
OBSERVE PRECAUTIONS
THIS PRODUCT COMPLIES WITH 21 CFR 1040.10
DANGER
INVISIBLE LASER RADIATION
AVOID DIRECT
EXPOSURE TO BEAM
OUTPUT POWER 21 mW
WAVELENGTH >1510 nm
CLASS III b LASER PRODUCT
Device Ordering Information
LC25ET [Wavelength]
[Power Option]
[Reach]
[Connector]
****
E = 2 mWpk
A = 175 km -
C28 = SC/PC
C = 3 mWpk
B = 360 km -
C34 = FC/PC
A = 4 mWpk
-
C57 = LC
B = High power
-
C59 = MU
Fibre Length 1130 to 1190 mm.
Other connector types are available on request.
**** = Last four digits of first channel / shortest wavelength
E.g. LC25ET4532CA-C28 has the following for channels:
1545.32 nm
1546.12 nm
1546.92 nm
1547.72 nm
The high power option provides 10 mW peak power at 175 km or 7 mW peak power
over 360 km
E.g. LC25ET4532BA-C28 is a 10 mW 1545.32 nm device with an SC connector
for use in a 175 km application.
E.g. LC25ET4532BB-C28 is a 7 mW 1545.32 nm device with an SC connector
for use in a 360 km application.
Lead trimming option
Devices can be supplied with the leads trimmed to a length of 3.81mm typ.
This option can be specified by adding a "K" suffix after the reach option.
E.g. LC25ET4532BAK-C28 is a 10mW 1545.32 nm device with an SC connector
and lead length of 3.81 mm typical, for use in a 175km application.
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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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