12
Quick Reference Guide
Figure 7
Laser diode test connections
Polarity
Polarity for the laser diode current source, both detector voltage bias sources, and laser
diode voltage measurement can be controlled by using the POLARITY selections in the
corresponding configuration menus:
Press CONFIG > LASER I
L
, LASER V
L
, or DETECTOR I
PD
> select POLARITY.
See Section 3 of the Model 2520 User’s Manual for details on polarity.
Remote command programming
Table 1
lists the SCPI commands to select polarity.
Table 1
SCPI commands for selecting polarity
Command
Description
:SENSe[1]:VOLTage:POLarity <polarity>
:SENSe2:CURRent:POLarity <polarity>
:SENSe3:CURRent:POLarity <polarity>
:SOURce[1]:CURRent:POLarity <polarity>
Set laser diode measure polarity (POSitive or NEGative).
Set detector #1 measure polarity.
Set detector #2 measure polarity.
Set laser diode source polarity (POSitive or NEGative).
CURRENT
OUTPUT
VOLTAGE
SENSE
CAT I
DETECTOR 1
DETECTOR 2
BIAS
CURRENT
INPUT
ISOLATION FROM EARTH: 10V MAX.
HI
HI
LO
LO
!
!
Model 2520 Testhead
Triax Cable
Triax Cable
Center
Conductor
Center
Conductor
Inner Shield
Detector 1
Detector 2
Voltage
Sense
Current
Output
Inner Shield
Shield
Outer Shield
(Chassis Ground)
Coax
Cables
BNC
Shields
Connected
Optional Earth
Ground
Connection
Back
Photodiode
Detector
Forward
Photodiode
Detector
Laser
Diode
