xmt5170-622 ETC-unknow, xmt5170-622 Datasheet - Page 3

• Manufacturer Part Number: xmt5170-622
• Description: Mb/s Logic Interface Laser Transmitter
• Manufacturer: ETC-unknow

XMT5170-622 Block Diagram
Functional Description
The ECL input allows operation
from many logic families and
both single-ended or differential
signals. For single-ended
operation both DATA and DATA
are internally tied to a V
unused input then requires no
connection or biasing.
The disable function disables the
laser bias and modulator. The
switching threshold is V
If this input is not connected the
module is enabled. This input
may be connected to a CMOS HI
or tied to V
432
DATA
DATA
DISABLE
CC
INPUT
ECL
to disable.
CC
BB
. The
–3.2 V.
MODULATOR
LASER
The module provides the
necessary bias and modulation
control to maintain the extinction
ratio at better than 10 dB and the
waveform is compliant with
SONET/SDH Eyemask standard
G.957.
The laser bias control loop
compensates for temperature
induced variations in laser
performance. The bias current
monitor indicates the amount of
dc current supplied to the laser.
(This is approximately the laser
threshold current).
CONTROL
DRIVER
LASER
LASER
LASER
BIAS
BIAS
PHOTODIODE
(REAR FACET
MONITOR)
LASER BIAS
MONITOR
REAR FACET
MONITOR
The rear facet monitor is a signal
proportional to the laser output
power. This can be used as part
of a HI/LO light alarm.
In the absence of data the laser
will emit a mean optical power
within the specified limits. The
extinction ratio and duty cycle
distortion are specified assuring a
50% duty cycle at the correct
data rate.