Data
sheet
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.
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.
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Figure 1: Schematic diagram
Parameters
Parameter
Threshold current (Ith)
Slope efficiency
2 mW
3 mW
4 mW
High Power (1)
(2)
1.3
(3)
(4)
-20dB
34
(5)
40
250
0.4
40
125
360
50
4.07
∆T
= 64°C
∆T
= 64°C
8 to 50°C
Over life & temperature
including chirp (6)
-9
0.09
+9
20.7
1000
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
1563
2
0.6
Unit
mA
mW/mA
mW/mA
mW/mA
mW/mA
dB
V
nm
dB
nm
dB
ps
µA
nA
kΩ
mA
V
nm/°C
GHz
RF input reflection coef (S11)
Forward voltage
Peak wavelength (λp)
Dispersion penalty
Time averaged spectral linewidth
Side-mode suppression
Optical rise/fall time
Monitor photo currents
Monitor dark current
Thermistor resistance
Heatpump current
Heatpump voltage
Change of
λ
with laser temp.
Optical Spectral Window
(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
Ω
measurement system, f = dc - 3 GHz.
(3) Submount temperature between 0°C & 40°C start of life to achieve required
λp.
(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
λ
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
So
λ
D
(
λ
)
=
(
λ −
03
)
ps
/(
nm
.
km
)
4
λ
4
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Absolute Maximum Ratings
Parameter
Case operating temperature
Laser submount operating temperature
Storage temperature
Laser current above Ith
Laser reverse voltage
Laser reverse current
Monitor diode bias
Heat Pump Current
Heatpump voltage
Fibre bend radius
30
Min
0
8
-40
Max
+70
50
85
100
1.0
10
-10
1
2.4
Units
°C
°C
°C
mA
V
µA
V
A
V
mm
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 8°C to 50°C 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.
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 2: Outline Drawing and Pinout Information
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4.12
Thinking optical solutions
Connections
Pin #
1
2
3
4
5
6
7
Function
Thermistor
Thermistor
Laser DC bias (-)
Monitor short anode (-)
Monitor cathode (+)
TEC (+)
TEC(-)
Pin #
8
9
10
11
12
13
14
Function
Case ground
Case ground
Monitor long anode (-)
Laser case ground
Laser modulation (-)
Laser case ground
N/C
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
µA
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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Device Ordering Information
LC25ET
[Wavelength]
****
[Power Option]
[Reach]
E
= 2 mWpk
A
= 175 km
C
= 3 mWpk
B
= 360 km
A
= 4 mWpk
B
= High power
[Connector]
-
C28
= SC/PC
-
C34
= FC/PC
-
C57
= LC
-
C59
= MU
North America
Bookham Technology Inc.
49 Buford Highway
Suwanee
GA 30024
USA
• Tel: +1 678 482 4021
• Fax: +1 678 482 4022
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.
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
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.
• 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.
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 III b LASER PRODUCT
THIS PRODUCT COMPLIES WITH 21 CFR 1040.10
CAUTION
STATIC SENSITIVE DEVICE
OBSERVE PRECAUTIONS
Certificate No. FM 15040
Certificate No. EMS 35100
www.bookham.com
REV 1 Feb 2003
© Bookham Technology 2003 Bookham & ASOC are registered trademarks of Bookham Technology plc
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