Advance Data Sheet
February 2000
C488-Type 2.5 Gbits/s
Tunable, Stabilized, Long-Haul Laser Transmitters
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Low-profile, 24-pin package
Laser bias monitor alarm
Laser back-facet monitor output
Transmitter-enable input
Applications
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SONET/SDH extended-reach
Extra long-haul, very dense, wave-division multi-
plexing (DWDM)
High-speed data communication
Digitized video
Offering multiple output power options and SONET/SDH com-
patibility, the C488-Type Tunable Laser Transmitters support
four wavelengths and can be remotely programmed.
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Features
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Description
The C488-Type 2.5 Gbits/s Laser Transmitters are
designed for use in transmission systems and high-
speed data communication applications. The trans-
mitter operates at the SONET OC-48 rate as well as
the ITU-T SDH rate of STM-16. The device supports
four wavelengths and uses an RS-232 interface to
control various transmitter functions, including aver-
age optical power, wavelength, and fine-power. In
addition, the interface allows access to the alarm and
monitoring outputs as well as the unit’s serial num-
ber.
The transmitters meet all present
Telcordia Technolo-
gies
* GR-253-CORE requirements and the ITU-T
G.957 and G.958 recommendations. They are also
ideally suited for extended-distance data and net-
working applications.
The C488 Transmitter features a 1.5
µ
m laser with an
electroabsorptive modulator and an integrated stabi-
lizer. The device is capable of 360 km or 640 km
transmission at 2.5 Gbits/s in DWDM systems at a
channel spacing of 50 GHz or less. By integrating the
modulator with the laser chip, the device offers a
compact, cost-effective solution for extended-reach
transmissions.
*
Telcordia Technologies
is a trademark of Bell Communications
Research, Inc.
Data rates to 2.5 Gbits/s
Long-haul transmission to 640 km
SONET and ITU-T compliant at OC-48 and
STM-16
Integrated Fabry-Perot Etalon stabilizer
— Replaces external wavelength lockers
Wavelength range, 1528.77 nm—1563.86 nm
Optical output power adjustment (
±
0.5 dB)
Extinction ratio
≥
11 dB
Wavelength remotely programmable over four
50 GHz ITU-T channels
Asynchronous serial interface for transmitter com-
munication
Dither signal input
Clocked or nonclocked operation with single-ended
or differential inputs
50
Ω
ac-coupled PECL compatible data and clock
inputs
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C488-Type 2.5 Gbits/s
Tunable, Stabilized, Long-Haul Laser Transmitters
Advance Data Sheet
February 2000
Description
(continued)
The versatile C488-Type transmitters are available at
wavelengths compatible with the ITU-T wavelength
standards at 200 GHz, 100 GHz, and 50 GHz. The
package also contains a thermoelectric cooler (TEC),
thermistor, back-facet monitor, and optical isolator. The
laser transmitter requires 5 V and –5.2 V power sup-
plies; the TEC operates on 3.3 V. The clock can be
enabled for those applications where jitter is critical.
Pin information is listed in Table 1.
Table 1. Pin Descriptions
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Name
Ground (TEC)
Back-facet Monitor *
Bias Monitor/Laser Degrade Alarm*
Tx Enable
Clock Select
Ground
Wavelength-Deviation Error Alarm
RS-232 Interface (Tx)
RS-232 Interface (Rx)
Dither Input
Ground
V
EE
V
CC
V
TEC
(TEC supply voltage)
Ground
DATA
Ground
DATA
Ground
CLOCK
Ground
CLOCK
Ground
V
CC
Transmitter Processing
The transmitter can withstand normal wave soldering
processes. The complete transmitter module is not her-
metically sealed; therefore, it should not be immersed
in or sprayed with any cleaning solution or solvents.
The process cap and fiber pigtail jacket can deform at
temperatures greater than 85
°
C. The transmitter pins
can be wave-soldered at a maximum temperature of
250
°
C for 10 seconds.
Installation Considerations
Although the transmitter has been designed with rug-
gedness in mind, care should be used during handling.
The optical connector should be kept free from dust,
and the process cap should be kept in place as a dust
cover when the device is not connected to a cable. If
contamination is present on the optical connector, the
use of canned air with an extension tube should
remove any debris. Other cleaning procedures are
identified in the
Cleaning Fiber-Optic Assemblies
Tech-
nical Note (TN95-010LWP).
* Laser back-facet and bias alarm functions are customer-use
options that are not required for normal operations of the transmit-
ter and are normally used during manufacture and for diagnostics.
The output will optionally be either a logic signal or an analog volt-
age. All alarm, select, and enable signals are active-high.
Connector Options
The standard fiber-optic pigtail is an 8
µ
m core single-
mode fiber in a 0.036 in. (914
µ
m) diameter, tight-buff-
ered outer jacket. The standard length is 39 in.
±
4 in.
(1 m
±
10 cm) and is terminated with an optical connec-
tor.
2
Lucent Technologies Inc.
Advance Data Sheet
February 2000
C488-Type 2.5 Gbits/s
Tunable, Stabilized, Long-Haul Laser Transmitters
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 operations sections of the data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability.
Parameter
Supply Voltage (positive)
Supply Voltage (negative)
Operating Case Temperature Range
Storage Case Temperature Range
Lead Soldering Temperature/Time
Relative Humidity (noncondensing)
Minimum Fiber-Bend Radius
Symbol
V
CC
V
EE
T
C
T
stg
—
RH
—
Min
—
—
0
–40
—
—
1.00 (25.4)
Max
5.25
–6.0
70
85
250/10
85
—
Unit
V
V
°
C
°
C
°
C/s
%
in. (mm)
Characteristics
(Min. and max. values specified over operating case temperature range at 50% duty cycle
data signal. Typical values are measured at room temperature unless otherwise noted.)
Table 2. Electrical Characteristics
Parameter
dc Power Supply Voltage
dc Power Supply Current
dc Negative Supply Voltage
dc Negative Supply Current
Power Dissipation
Input Data/Clock Voltage:
1, 2
Single-ended Input
Differential Input
Clocked/Nonclocked Select Voltage:
3
Clocked Operation (V
IL
)
Nonclocked Operation (V
IH
)
Input Impedance
Transmitter Disable Voltage (TTL) V
IH
Transmitter Enable Voltage (TTL) V
IL
λ
Deviation Alarm: Levels (CMOS) V
OL
λ
Deviation Alarm: Levels (CMOS) V
OH
Setting
4
Laser Degrade Alarm: Levels (CMOS) V
OH
Laser Degrade Alarm: Levels (CMOS) V
OL
Setting
Symbol
V
CC
I
CC
V
EE
I
CC
P
DISS
V
IN
V
IN
V
SEL_CLK
V
DIS_CLK
R
IN
V
DIS
V
EN
V
λ
ALARM N
V
λ
ALARM
λ
ALARM
V
ALARM
V
λ
ALARM N
LD
ALARM
Min
4.75
—
–5.46
—
—
250
125
0.0
2.0
—
2.0
0.0
0
4.5
–20
4.5
0
—
Typ
5.0
350
–5.2
—
4.5
900
450
—
—
50
—
—
—
—
—
—
—
—
Max
5.25
500
–4.94
250
6.5
1300
650
0.8
V
CC
—
V
CC
0.8
0.4
V
CC
20
V
CC
0.4
60
Unit
V
mA
V
mA
W
mVp-p
mVp-p
V
V
Ω
V
V
V
V
pm
V
V
mA
1. Inputs are ac-coupled internally into an equivalent input impedance of 50
Ω
.
2. Single-ended or differential operation may used. If the inputs are driven single-ended, the unused inputs must be terminated in 50
Ω
.
3. Clocked operation is optional. For clocked operation, pin 5 must be a logic 1. With clocked operation, the optical output changes state with
the rising edge of the input clock signal.
4. Deviation due to temperature variation detected by the thermistor.
Lucent Technologies Inc.
3
C488-Type 2.5 Gbits/s
Tunable, Stabilized, Long-Haul Laser Transmitters
Advance Data Sheet
February 2000
Characteristics
(continued)
Table 2. Electrical Characteristics
(continued)
Parameter
Laser Bias Monitor Voltage
Laser Monitor Voltage (50% duty cycle)
5
TEC Current
TEC Voltage
Setup Time
Hold Time
Clock Duty Cycle
Return Loss:
Input Data
6
Input Clock
7
Symbol
V
LBM
V
BF
I
TEC
V
TEC
T
SET
T
HOLD
C
DC
RL
DATA
RL
CLOCK
Min
—
—
—
3.0
—
Typ
20
500
0.6
3.3
—
—
50
—
—
Max
—
—
1.3
3.5
35
—
60
—
—
Unit
mV/mA
mV/mW
A
V
ps
ps
%
dB
dB
60
40
–10
–12
1. Inputs are ac-coupled internally into an equivalent input impedance of 50
Ω
.
2. Single-ended or differential operation may used. If the inputs are driven single-ended, the unused inputs must be terminated in 50
Ω
.
3. Clocked operation is optional. For clocked operation, pin 5 must a logic 1. If pin 5 is left floating, the transmitter operates in the clocked mode.
With clocked operation, the optical output changes state with the rising edge of the input clock signal.
4. Deviation due to temperature variation detected by the thermistor.
5. This voltage is measured from Pin 2 to GND.
6. Frequency range: 100 kHz—2 GHz.
7. At frequency of 2.5 GHz.
t
SET
t
HOLD
1-1087 (F)
Figure 1. Electrical Input/Output Interface Timing Diagram
4
Lucent Technologies Inc.
Advance Data Sheet
February 2000
C488-Type 2.5 Gbits/s
Tunable, Stabilized, Long-Haul Laser Transmitters
Characteristics
(continued)
Table 3. Optical Characteristics
Parameter
Average Optical Power Output:
1
BOL
EOL
Output Power Variation (BOL)
Wavelength Accuracy (room temperature)
Center Wavelength Range (See Table 5.)
Variation in Center Wavelength over Temperature
Range (EOL, all causes)
Side-mode Suppression Ratio
2
Jitter, Intrinsic (12 kHz—20 MHz)
3
Extinction Ratio
4
Eye Mask of Optical Output
5, 6
Optical Rise/Fall Time (20%—80%)
Maximum Return Loss (optical)
Symbol
P
AVG BOL
P
AVG EOL
∆P
∆λ
C
λ
C
∆λ
T
SMSR
—
r
e
—
t
R,
t
F
O
RL
Min
–2.0
TBD
–0.5
–0.015
1528.77
–0.016
30
—
11.0
—
—
Typ
—
—
—
—
—
—
—
—
—
—
—
Max
2
TBD
0.5
0.015
1563.86
0.016
—
0.05
—
125
24
Unit
dBm
dBm
dBm
nm
nm
nm
dB
UIp-p
dB
—
ps
dB
Meets SONET and ITU-T
1. Output power definitions and measurement per ITU-T Recommendation G.957.
2. Ratio of the average output power in the dominant longitudinal mode to the power in the most significant side mode under fully
modulated conditions.
3. Filter bandwidth from 12 kHz—20 MHz, according to ITU-T G813.
4. Ratio of logic 1 output power to logic 0 output under fully modulated conditions.
5. GR-253-CORE,
Synchronous Optical Network (SONET) Transport Systems: Common Generic Criteria.
6. ITU-T Recommendation G.957,
Optical Interfaces for Equipment and Systems Relating to the Synchronous Digital Hierarchy.
Table 4. Dispersion Performance
Parameter
Dispersion Penalty for Extended Reach (360 km)
Dispersion Penalty for Extended Reach (640 km)
Symbol
DP
DP
Test
Conditions
6400 ps/nm
10500 ps/nm
Min
—
—
Typ
—
—
Max
2.0
2.0
Unit
dB
dB
Lucent Technologies Inc.
5
Power technology
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