TX 20622
622 Mb/s DIGITAL TRANSMITTER MODULE
DESCRIPTION
The TX20622 product is a high performance, cost
effective module for serial data communication
applications specified for a data rate up to 622
Mb/s.
This Transmitter integrates a 1300nm Fabry Perot
laser diode optically coupled into a single mode
fiber. The output power is controlled through a
specific circuit via a monitor photodiode. The
electronic circuit provides two controls which
maintain constant the output optical power level
both for a digital ‘one’ and a digital ‘zero’ on the
input. These two loops compensate effects due to
thermal
variations
on
the
laser
diode
characteristics. So, the transmitter circuit can
operate from -40°C to +85°C.
When there is no input digital stream, the loop is
blocked to protect the laser for the case of
appearance of a new signal. An alarm is provided
in that case.
Another alarm is provided when current into the
laser goes up to 150% of the initial value.
A digital interface, between digital inputs and laser
driver circuit, controls the peak to peak voltage to
the laser modulator input. So, variations can be
accepted on the digital input levels.
MAIN FEATURES : APPLICATIONS
•
SONET OC-12 / SDH STM 4 Equipment Interconnect and ATM applications
•
Data link
•
Fiber in the loop
TX 20622
SPECIFICATIONS
Operationg Case Temperature: - 40°C to + 85°C
PARAMETERS
Wavelength
Spectral width (rms)
Average optical power
(*)
Min.
1260
Typ.
1310
4
Max.
1340
7
-8
UNITS
nm
nm
dBm
dB
-12
- 10
+ 1.5
Optical power stability (-40°C to +85°C)
Extinction ratio
Bit rate ( 2
23
8
20
12
622
17
dB
Mb/s
- 1 PRBS NRZ)
Data inputs
Alarm on (Laser current limitation)
Alarm off (Laser current limitation)
No input signal alarm on
No input signal alarm off
Thermistor at +25°C
Thermistor coefficient
Positive supply voltage
Positive supply current
(**)
Negative supply voltage
Negative supply current
(**)
DC power consumption
(**)
(*)
(**)
ECL 10K compatible
+4
1
+4
1
10
4
+ 4.75
60
- 4.75
150
1
-5
+5
+ 5.25
80
- 5.25
250
1.7
V
V
V
V
kΩ
% / °C
V
mA
V
mA
W
measured at point S in accordance with CCITT G. 957
Depending on the case temperature
TX 20622
ABSOLUTE MAXIMUM RATINGS
PARAMETERS
Positive supply voltage
Negative supply voltage
Fiber bending radius
Operating Case Temperature range
Storage Temperature
Min.
Max.
+6
-6
40
UNITS
V
V
mm
°C
°C
-40
-40
+85
+85
Information furnished is beleived to be accurate and reliable. However THOMSON-CSF LASER DIODES assumes no
responsability for the consequences of use of such information nor for any infringement of patents or other rights of third
parties which may result from its use. Specifications mentioned in this document are subjected to change without notice.
Copyright C 1997 THOMSON-CSF Laser Diodes
http://www.laser-diodes.thomson-csf.com.
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