Table of Contents
Advertisement
Step 2: Coarse Calibration Adjustment
Refer to the schematic in Figure 1 and the drawing
in Figure 2 for the locations of measurements and
components.
2-1. Connect the attenuator output to the reference
power meter.
For the remaining calibration
adjustments, use the cable used in step
2-1 for connecting the attenuator output
to the reference power meter or the FOM.
2-2. Set the attenuator to 0 dBm. Set the
1300 nm light source to -10 dBm ±0.05 dBm.
Record the level shown on the reference
power meter as P in (power in) for use in step
2-6.
2-3. Connect the attenuator output to the FOM.
2-4. Measure V det between U1 pin 7 and the
analog ground reference at U1 Pin 4. Adjust
R2 for 0.3 V ±0.01 V dc.
2-5. Measure V ref between U2 pin 1 and the
analog ground reference at U1 Pin 4. Record
this value for use in the transfer function
calculations.
2-6. Use the following transfer function to
calculate Vo:
9R =
V
× −
ref
53 dBm
2-7. Measure between DBout at U2 pin 7 and the
analog ground reference at U1 Pin 4. Adjust
R10 for Vo (as calculated in step 2-6)
±0.0005 V.
Step 3: 1300 nm Fine Calibration
Adjustment
3-1. Connect the attenuator output to the reference
power meter. Set the attenuator output to
-45 dBm ±0.1 dBm. Record the value shown
on the reference power meter as P in for step
3-3.
3-2. Connect the attenuator output to the FOM.
Note
(
)
( )
+
P
3 dBm
in
Service Information Sheet for Serial Numbers < 79370000
3-3. Use P in from step 3-1, V ref from step
2-5, and the transfer function below to
calculate Vo:
9R =
3-4. Measure between DBout at U2 pin 7 and the
analog ground reference at U1 Pin 4. Use the
formula below to calculate V n:
Vn =
3-5. Adjust R10 for V n ±0.0005 V at DBout.
3-6. Connect the attenuator output to the reference
power meter. Set the attenuator for a power
meter reading of -10 dBm ±0.1 dBm.
3-7. Connect the attenuator output to the FOM.
Adjust R2 for Vo ±0.0005 V (as calculated in
step 2-6) at DBout.
3-8. Repeat steps 3-1 through 3-7 until the FOM's
-10 dBm and -45 dBm readings are within
specifications.
Step 4: 850 nm Fine Calibration
Adjustment
4-1. Set the switch on the FOM to the 850 nm
position.
4-2. Set the 850 nm light source to -10 dBm
±0.05 dBm. Use the reference power meter to
measure the source output power level.
Record this level as P in for use in step 4-4.
4-3. Connect the 850 nm light source to the FOM.
4-4. Use P in from step 4-2, V ref from step
2-5, and the transfer function below to
calculate Vo:
9R =
4-5. Measure between DBout at U2 pin 7 and the
analog ground reference at U1 Pin 4. Adjust
R1 for Vo (as calculated in step 4-4)
±0.0005 V.
Calibration Adjustments
V
(
( )
× −
+
ref
P
in
53 dBm
DBout - Vo (from step 3 - 3)
2
V
(
( )
× −
+
ref
P
in
53 dBm
)
3 dBm
)
3 dBm
5
Advertisement
Table of Contents
