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HP
70810B
Lightwave
Section
and
HP
70810B
Option
850
Lightwave
Section
W
ARNING
T
o
avoid
the
possibility
of
damage
to
your
eyes
,
verify
a
disabled
output
at
the
light
source
before
any
cleaning,
connecting,
or
disconnecting
of
optical
system
components
.
The
HP
70810B
lightwave
section
is
a
1/8-width
module
.
The
lightwave
section
provides
a
wavelength
measurement
range
of
1200
nm
to
1600
nm
(750
nm
to
870
nm
for
an
Option
850)
and
a
detected
modulation
bandwidth
of
100
kHz
to
22
GHz
with
an
input
noise
equivalent
power
of
064
dBm/
p
Hz
.
Lightwave
section
features
include
HP-IB
and
HP-MSIB
communication
capability
and
both
optical
and
electrical
input
connectors
.
The
module
can
operate
as
either
a
standard
slave
module
or
as
an
independent
module
(stand-alone
operation).
Typically
,
the
HP
70810B
lightwave
section
precedes
the
RF
section
in
a
modular
electrical
spectrum
analyzer
,
such
as
an
HP
71210C
microwave
spectrum
analyzer
or
an
HP
71100C
modular
spectrum
analyzer
.
An
electrical
spectrum
analyzer
congured
with
an
HP
70810B
lightwave
section
is
a
lightwave
signal
analyzer
.
The
lightwave
system
detects
and
displays
intensity
modulation
present
on
a
lightwave
signal
transmitted
on
single-mode
optical
ber
.
The
displayed
intensity-modulation
incorporates
frequency-response
calibration
corrections
that
compensate
for
photodetector
responsivity
and
preamplier
gain
variations
.
The
factory
determines
responsivity
values
for
1300
nm
and
1550
nm
wavelengths
(850
nm
for
an
Option
850).
The
user
can
select
one
of
these
values
or
calibrate
the
lightwave
section
to
some
other
reference
.
Basically
the
HP
70810B
lightwave
section
consists
of
optical
attenuator
,
broadband
photodetector
,
microwave
preamplier
,
and
optical
power
meter
.
The
lter-wheel
attenuator
provides
up
to
30
dB
of
optical
attenuation
programmed
in
1
dB
steps
.
A
lens
focuses
the
light
onto
a
high-speed
PIN
photodetector
,
which
detects
the
modulation
and
converts
optical
power
to
electrical
current
(photons
to
electrons).
One
path
for
the
detected
current
drives
the
high-gain,
low
noise
,
four-stage
preamplier
,
which
consists
of
four
traveling-wave
GaAs
MMICs
(Gallium-Arsenide
Microwave-Monolithic
Integrated
Circuit).
The
preamplier
typically
provides
32
dB
gain
and
an
8
dB
noise
gure
from
100
kHz
to
22
GHz.
A
second
path
monitors
the
detected
current's
dc
component
with
a
transimpedance
circuit,
which
determines
a
value
representing
average
optical
power
.
(The
average
power
value
appears
on
a
lightwave
signal
analyzer
display
as
both
a
real-time
vertical
power
bar
and
a
digital
power
readout.)
A
softkey
function
connects
the
RF
input
to
the
RF
output,
thus
bypassing
all
optical
hardware
to
allow
conventional
electrical
spectrum
analyzer
operation
without
removing
the
HP
70810B
lightwave
section
from
the
modular
measurement
system.
In
a
stand-alone
conguration,
the
HP
70810B
lightwave
section
electrical
output
is
the
amplied,
uncorrected,
detected
intensity
modulation.
The
function
of
the
power
meter
is
unchanged
when
the
lightwave
section
is
congured
for
stand-alone
operation.
B-12
Input
and
Output
P
orts
Содержание 70000 series
Страница 42: ...Auxiliary Measurement Indicators Figure 1 8 Auxiliary Measurement Indicators Overview 1 19 ...
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Страница 346: ...Figure A 2 Simpli ed Lightwave Signal Analyzer Block Diagram Theory of Operation A 3 ...
Страница 366: ...Figure B 6 HP 70620A B Preampli er and HP 70621A Preampli er Front View Input and Output Ports B 11 ...
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