LS-1310/1550
Laser Source
Service Information Sheet
Introduction
This Service Information Sheet provides the
following service information for the LS-1310/1550
Laser Source (hereafter referred to as "the laser
source").
• Precautions and safety information
• Parts and service information
• Specifications
• Cleaning procedures
• Required equipment
• Performance tests
• Calibration adjustments
• Diagrams showing calibration measurement
and adjustment points
• Parts and accessories lists
For operating instructions, refer to the
LS-1310/1550 Laser Source Instruction Sheet.
Precautions and Safety Information
• Always clean the fiber optic connectors before
use.
• Before testing, let the laser source stabilize for
2 minutes after you turn it on.
Warning: Class I Laser Product
To avoid injury, do not service the
source unless you are qualified to do so.
To avoid possible exposure to
hazardous laser radiation and to prevent
eye damage
Never look directly into the source
connector. Though the laser radiation is
invisible, it can damage your eyes.
Do not modify the source.
Do not magnify or otherwise modify the
laser output. Use only approved
connectors and adapters.
Do not use controls, adjustments, or
procedures not documented or approved
by Fluke Corporation.
Caution
While servicing the laser source, always
follow guidelines for preventing
electrostatic discharge (ESD). Otherwise,
ESD can damage sensitive compone nts,
causing immediate or delayed failure of
the source.
Parts and Service
The source is warranted to be free from defects in
material and workmanship for one year, while
under normal use. Parts and repairs are warranted
for 90 days. Refer to the laser source instruction
sheet for the complete warranty statement.
To order parts, or for warranty service, contact
Fluke as follows:
U.S.A.: 1-888-993-5853
Canada: 1-800-363-5853
Europe: +31-402-675-200
Japan: +81-3-3434-0181
Singapore: +65-738-5655
Anywhere in the world: +1-425-446-4519
For operating assistance in the USA, call
1-800-283-5853.
Visit the Fluke Networks web site at
www.flukenetworks.com.
PN 688967
November 1997, Rev. 1, 9/01
1997, 2001 Fluke Networks, Inc. All rights reserved. Printed in USA. Product names are trademarks of their respective companies.
LS-1310/1550
Laser Source
Specifications
Accuracy is specified for a period of one year after
calibration, at 18 °C to 28 °C (64 °F to 82 °F) with
relative humidity to 90%. Specifications are shown
in Table 1.
Table 1. Specifications
Emitter Type Laser
Laser
Classification
Safety Complies with ANSI/ISA S82.01-
Output
Wavelengths
Output Connector Singlemode ST
Output Power
(CW)
Output Level
Stability
Temperature
Range
Power Source 9 V battery
Size 17.4 cm x 7.6 cm x 3.8 cm
Weight 266 g (9.38 oz)
Battery Life 16 hours typical (alkaline)
Indicators SOURCE ACTIVE (power on)
Class 1
1994, CSA C22.2 No. 1010.1-92,
EN61010.1: 1993
1310 nm ±20 nm
1550 nm ±30 nm
-10 dBm (100 µW) adjustable
At 25 °C after a 15-minute
warm-up:
±0.2 dB over 1 hour
±0.4 dB over 8 hours
Operating: 0 °C to 40 °C
Storage: -10 °C to +60 °C
(6.9 in x 3.0 in x 1.5 in)
LED
LOW BATTERY LED
Cleaning the Optical Connector
Most problems with optical sources result from
contaminated connectors. Therefore, always clean
the connector before troubleshooting or calibration.
To clean the source connector, wipe it gently with
an optical-grade tissue or swab dampened with
optical-grade alcohol. To remove loose dirt and
dust from the connector, use filtered, compressed
air.
Always cover the connector with a dust cap when
the unit is not in use.
Required Equipment
The following equipment is required for
performance tests and calibration adjustments:
• Fiber optic power meter calibrated at 1310 nm
and 1550 nm
• 0-10 V dc adjustable power supply with a
minimum output of 500 mA and a current-limit
adjustment
• Fluke 187 DMM (digital multimeter),
equivalent, or better
• 20 MHz digital or analog oscilloscope,
equivalent, or better
• Optical power meter (OPM) traceable to local
national standards
• ST/ST singlemode fiber patch cable
Note
Using a multimode fiber patch cable will
cause calibration errors.
Performance Tests
Use the performance tests to confirm that the
source is working properly. If the source fails any
of these tests, clean the fiber connectors, verify that
the connections are solid, then retest the laser
source. If the source still fails a test, it needs
calibration adjustments or repair.
1. Turn on the optical power meter (OPM).
2. Set the laser source's power switch to 1310 nm.
Verify that the
briefly before the
on. Let the laser source stabilize for 5 minutes.
3. Using a singlemode fiber patch cable, connect
the laser source to the OPM.
4. Set the OPM to measure 1310 nm. Set the laser
source's
5. Verify that the power reading is -10.00 dBm
±0.5 dB.
6. Set the laser source’s CW/MOD switch to
MOD. Verify that the power reading increases
by 0.6 dBm +0.3 dB.
7. Set the laser source's CW/MOD switch to CW;
set the power switch to 1550 nm. Set the OPM
to measure 1550 nm.
8. Repeat steps 5, 6, and 7.
9. Turn off the laser source. Disconnect the fiber
patch cable; then install the dust caps on the
source.
LOW BATTERY LED flashes
SOURCE ACTIVE LED turns
CW/MOD switch to CW.
2
Service Information Sheet
Calibration Adjustments for Serial Numbers
<
79130000
Calibration Adjustments for Serial
Numbers < 79130000
(for later serial numbers, see page 6)
To ensure that the laser source performs to
specifications, calibrate it annually using the
procedure that follows.
Always perform the complete calibration
adjustment procedure.
Step 1: Preparing for Calibration
Before you start the calibration procedures
described in this sheet, do the following (refer to
Figure 1 for locations of components on the circuit
board):
1-1. Turn off the laser source.
1-2. Remove the battery door and the 9 V battery.
1-3. Remove the four Phillips screws from the back
of the source. Remove the top case.
1-4. Unscrew the external retaining nuts from the
source’s power switch and
1-5. Carefully remove the laser source circuit board
from the bottom case. Take care to not strain
the fiber that connects the circuit board to the
ST connector mounted in the bottom case.
1-6. Before applying power to the source, do the
following:
a. Remove the jumpers from J2 and J4.
b. Adjust the internal potentiometers R4 and
R14 to their full counterclockwise
positions. You will hear a faint click at the
full counterclockwise position.
c. Adjust the external
potentiometers (R24 and R35) to their full
clockwise positions. You will hear a faint
click at the full clockwise position.
1-7. Adjust the dc power supply to 10 V ±0.25 V
with the output current limited to 250 mA.
Connect the power supply's positive lead to
BT1 on the source; connect the negative lead
to BT2.
1-8. Set the laser source's
CW position.
CW/MOD switch.
OUTPUT ADJUST
CW/MOD switch to the
1-9. Set the laser source's power switch to either
the 1310 nm or 1550 nm position. Verify that
the laser source
and the
SOURCE ACTIVE LED is on.
LOW BATTERY LED is off
Step 2: Checking the Laser Drive Voltage
Use the following procedure to check the drive
voltage for the laser diodes and to verify that the
laser source's low battery detection circuit is
operating properly.
2-1. Set up the DMM to measure dc voltage.
Connect the DMM to the laser drive voltage
between J2-6 and J2-4 (Gnd). Verify that the
voltage is between 3.2 V dc and 3.5 V dc.
Record this measurement for use in the next
step.
Note
To avoid overshooting the target voltage in the
next step, slow the adjustment rate on the
power supply as the voltage approaches 7 V.
2-2. Decrease the power supply voltage just until
the laser source's
Verify the following:
a. The power supply voltage is between
5.4 V dc and 6.2 V dc.
b. The DMM reading has changed less than
0.3 V dc from the reading you recorded in
step 1.
2-3. Connect the DMM's positive lead to U3-5.
Verify the reading to be < 500 mV dc.
2-4. Turn off the laser source and the power
supply. Remove the power supply leads from
the laser source's battery terminals.
2-5. Reassemble the bottom case, as follows:
a. Verify that the star washers are in place at
the bases of the laser source switches; then
carefully reinstall the PCA into the bottom
case. Ensure that the fiber connecting the
circuit board to the ST connector is not
pinched between the board and the case.
b. Reinstall the external retaining nuts on the
laser source's power switch and
switch.
LOW BATTERY LED lights.
CW/MOD
3
LS-1310/1550
Laser Source
SW1 SW2
U3
R24
R35
BT1 BT2R35R24U3
Front
J2J4R14 R4
J2
J4
R14
R4
Back
Figure 1. Jumpers and Calibration Measurement and Adjustment Points for SN < 79130000
nu01f.eps
4
Service Information Sheet
Calibration Adjustments for Serial Numbers
<
79130000
Step 3: Calibrating and Adjusting the 1310 nm Circuit
Use the following procedure to make calibration
adjustments to the 1310 nm laser diode circuit and
to calibrate the 1310 nm modulation circuit:
3-1. Adjust the dc power supply to 9 V dc
±0.25 V dc. Connect the supply's positive
lead to BT1; connect the negative lead to
BT2.
3-2. Set up the DMM to measure dc current less
than 300 mA. Connect the DMM's positive
lead to J4-1; connect the negative lead to J4-
2.
3-3. Use a singlemode fiber patch cable to connect
the laser source to the OPM. Set the OPM to
measure 1310 nm.
WCaution
In the following steps, do not exceed
the laser diode’s maximum operating
current of 60 mA. Doing so can damage
the laser diode. If the current reaches
60 mA before the optical power reading
reaches -9.2 dBm, clean the ST
connectors or repair the laser source.
3-4. Set the laser source to 1310 nm. Verify that
the laser diode current is less than 60 mA.
WCaution
In the next step, slow the adjustment
rate on R4 as the optical power reading
approaches -14 dBm. If you turn R4 too
quickly, you might overshoot the
-9.2 dBm target and exceed the laser
diode’s maximum cur rent of 60 mA.
3-5. Adjust R4 clockwise until the either the
power reading is -9.2 dBm ±0.1 dB or the
current reaches 60 mA. A typical current
value is 15 mA at -9.2 dBm. If the current
reaches 60 mA before the power reading
reaches -9.2 dBm, the laser source requires
repair.
3-7. With the laser source set to 1310 nm, verify
that the power reading is -9.2 dBm ±0.1 dB.
3-8. Adjust the 1310 nm external potentiometer
(R24) counterclockwise to verify that the
laser source output is adjustable to
-11.2 dBm ±0.1 dB.
3-9. Adjust R24 until the laser source output
reads -10.0 dBm ±0.1 dB.
3-10. While the laser source is on, disconnect the
power supply; then install a 9 V battery.
Verify that the output is still at -10.0 dBm
±0.1 dB.
3-11. Connect an oscilloscope across J4-1 and J4-4
(Gnd). Set the laser source's
CW/MOD
switch to the MOD position.
3-12. Verify that the power reading is -10 dBm
±0.5 dB. Verify that the signal frequency is
2 kHz ±100 Hz with a duty cycle of 50%
±5%.
3-13. Set the laser source's
CW. Turn off the laser source. Remove the
CW/MOD switch to
9 V battery.
Step 4: Calibrating and Adjusting the 1550 nm Circuit
Use the following procedure to make calibration
adjustments to the 1550 nm laser diode circuit and
to calibrate the 1550 nm modulation circuit:
4-1. Adjust the dc power supply to 9 V dc
±0.25 V dc. Connect the supply's positive
lead to BT1; connect the negative lead to
BT2.
4-2. Set up the DMM to measure dc current less
than 300 mA. Connect the DMM's positive
lead to J2-1; connect the negative lead to
J2-2.
4-3. Use a singlemode fiber patch cable to connect
the laser source to the OPM. Set the OPM to
measure 1550 nm.
3-6. Turn off the laser source. Disconnect the
current meter. Reinstall the jumper between
J4-1 and J4-2.
5
LS-1310/1550
Laser Source
WCaution
In the following steps, do not exceed
the laser diode’s maximum operating
current of 60 mA. Doing so can damage
the laser diode. If the current reaches
60 mA before the optical power reading
reaches -9.2 dBm, clean the ST
connectors or repair the laser source.
4-4. Set the laser source to 1550 nm. Verify that
the laser diode current is less than 60 mA.
WCaution
In the next step, slow the adjustment
rate on R14 as the optical power reading
approaches -14 dBm. If you turn R14 too
quickly, you might overshoot the
-9.2 dBm target and exceed the laser
diode’s maximum cur rent of 60 mA.
4-5. Adjust R14 clockwise until either the power
reading is -9.2 dBm ±0.1 dB or the current
reaches 60 mA. A typical current value is
25 mA at -9.2 dBm. If the current reaches
60 mA before the power reading reaches
-9.2 dBm, the laser source requires repair.
4-6. Turn off the laser source. Disconnect the
DMM. Reinstall the jumper between J2-1
and J2-2.
4-7. With the laser source set to 1550 nm, verify
that the power reading is -9.2 dBm ±0.1 dB.
4-8. Adjust the 1550 nm external potentiometer
(R35) counterclockwise to verify that the
laser source output is adjustable to
-11.2 dBm ±0.1 dB.
4-9. Adjust R35 until the laser source output
reads -10.0 dBm ±0.1 dB.
4-10. While the laser source is on, disconnect the
power supply; then install a 9 V battery.
Verify that the output is still at -10.0 dBm
± 0.1 dB.
4-11. Connect an oscilloscope across J2-1 and J2-4
(Gnd). Set the laser source
MOD position.
to the
CW/MOD switch
4-12. Verify that the power reading is -10 dBm
±0.5 dBm. Verify that the signal frequency
is 2 kHz ±100 Hz with a duty cycle of 50%
±5%.
Step 5: Reassembly and Final Test
5-1. Remove the singlemode cable from the laser
source. Put the dust cap onto the laser source
optical ST connector.
5-2. Apply insulating varnish, such as red GLPT,
to all potentiometers adjusted.
5-3. Put the board back in the case. Put the case
halves together and install the four Phillips
screws. Reinstall the lock washers and nuts to
the CW/MOD and 1550/1310 switches.
Install a 9 V battery and the battery door.
5-4. Run the performance tests as described in the
earlier section "Performance Tests".
Calibration Adjustments for Serial
Numbers
(For earlier serial numbers, see page 3)
To ensure that the laser source performs to
specifications, calibrate it annually using the
procedure that follows.
Always perform the complete calibration
adjustment procedure.
Step 1: Preparing for Calibration
Before you start the calibration procedures
described in this sheet, do the following (refer to
Figure 2 for locations of components on the circuit
board):
1-1. Turn off the laser source.
1-2. Remove the battery door and the 9 V battery.
1-3. Remove the four Phillips screws from the
back of the laser source. Remove the top case.
1-4. Unscrew the external retaining nuts from the
laser source's power switch and
switch.
1-5. Carefully remove the laser source circuit
board from the bottom case. Take care to not
strain the fiber that connects the circuit board
to the ST connector mounted in the bottom
case.
≥
79130000
CW/MOD
4-13. Set the laser source
Turn off the laser source.
6
CW/MOD switch to CW.
Service Information Sheet
Calibration Adjustments for Serial Numbers
≥
79130000
1-6. Before applying power to the laser source, do
the following:
a. Adjust the internal potentiometers R39
and R40 to their full counterclockwise
positions. You will hear a faint click at
the full counterclockwise position.
b. Adjust the external OUTPUT ADJUST
potentiometers (R12 and R31) to their full
counterclockwise positions. You will hear
a faint click at the full counterclockwise
position.
1-7. Adjust the dc power supply to 9 V ±0.25 V
with the output current limited to 250 mA.
Connect the power supply’s positive lead to
BT1+ on the laser source, connect the
negative lead to BT1-.
1-8. Set the laser source's
CW position.
CW/MOD switch to the
1-9. Set the laser source's power switch to either
the 1310 nm or 1550 nm position. Verify that
the laser source
and the
SOURCE ACTIVE LED is on.
LOW BATTERY LED is off
Step 2: Checking the Laser Drive Voltage
Use the following procedure to check the drive
voltage for the laser diodes and to verify that the
laser source's low battery detection circuit is
operating properly.
2-1. Connect negative probe of DMM to TP2
(Gnd).
2-2. Turn laser source to either 1310 nm or
1550 nm, set the CW/MOD switch to the CW
position.
2-3. With the DMM verify the voltage of Z5 pin 8
is 1.23 V ±0.04 V.
2-4. Check the voltage on the plus (+) side of C13,
verify it is 5 V ±0.2 V.
2-5. Decrease the power supply voltage just until
the laser source's
2-6. Verify the power supply voltage is 5.9 V
±0.2 V.
2-7. Reverify voltage on plus (+) side of C13 is
5 V ±0.2 V.
LOW BATTERY LED is lit.
Step 3: Calibrating and Adjusting the 1310 nm Circuit
Use the following procedure to make calibration
adjustments to the 1310 nm laser diode circuit:
3-1. Adjust the dc power supply to 9 V ±0.25 V
with the output current limited to 250 mA.
Connect the power supply's positive lead to
BT1+; connect the negative lead to BT1-.
3-2. Set up the DMM to measure dc volts less than
2 V. Connect the negative probe to TP2 (Gnd)
and the positive to the side of R20 furthest
from Z2. To calculate current in the 1310 nm
laser drive use the equation I = V/22.
3-3. Use a singlemode fiber patch cable to connect
the laser source to the OPM. Set the OPM to
measure 1310 nm.
WCaution
In the following steps, do not exceed
the laser diode’s maximum operating
current of 60 mA. Doing so can damage
the laser diode. If the current reaches
60 mA before the optical power reading
reaches -9.2 dBm, clean the ST
connectors or repair the laser source.
3-4. Set the laser source to 1310 nm. Turn R12 to
full clockwise position.
WCaution
In the next step, slow the adjustment
rate on R39 as the optical power reading
approaches
-14 dBm. If you turn R39 too quickly,
you might overshoot the -9.2 dBm target
and exceed the laser diode’s maximum
current of 60 mA.
3-5. Adjust R39 clockwise until either the power
reading is -9.2 dBm ±0.1 dB or the current
reaches 60 mA. A typical current value is
15 mA at -9.2 dBm. If the current reaches
60 mA before the power reading reaches
-9.2 dBm, the laser source requires repair.
3-6. With the laser source set to 1310 nm, verify
that the power reading is -9.2 dBm ±0.1 dB.
3-7. Adjust the 1310 nm external potentiometer
(R12) counterclockwise to verify that the
laser source output is adjustable to -11.2 dBm
±0.1 dB.
3-8. Adjust R12 until the laser source output reads
-10.0 dBm ±0.1 dB.
7
LS-1310/1550
Laser Source
TP2
R20
Z5
TP1
Z2
R12 R31
R29
R39
C13+
R2
R40
BT1+
BT1-
Figure 2. Calibration Measurement and Adjustment Points for SN ≥ 79130000
nu02f.eps
8
Service Information Sheet
Calibration adjustments for Serial Numbers
≥
79130000
Step 4: Calibrating and Adjusting the 1550 nm Circuit
Use the following procedure to make calibration
adjustments to the 1550 nm laser diode circuit.
4-1. Adjust the dc power supply to 9 V ±0.25 V.
Connect the supply's positive lead to BT1+;
connect the negative lead to BT1-.
4-2. Set up the DMM to measure dc volts less than
2 V. Connect the negative probe to TP2 (Gnd)
and the positive to the side of R2 furthest
from the board edge. To calculate current in
the 1550 nm laser drive use the equation
I = V/22.
4-3. Use a singlemode fiber patch cable to connect
the laser source to the OPM. Set the OPM to
measure 1550 nm.
WCaution
In the following steps, do not exceed
the laser diode’s maximum operating
current of 60 mA. Doing so can damage
the laser diode. If the current reaches
60 mA before the optical power reading
reaches -9.2 dBm, clean the ST
connectors or repair the laser source.
4-4. Set the laser source to 1550 nm. Turn R31 to
the full clockwise position.
WCaution
In the next step, slow the adjustment rate
on R40 as the optical power reading
approaches -14 dBm. If you turn R40 too
quickly, you might overshoot the -9.2 dBm
target and exceed the laser diode’s
maximum current of 60 mA.
4-5. Adjust R40 clockwise until either the power
reading is -9.2 dBm ±0.1 dB or the current
reaches 60 mA. A typical current value is
15 mA at -9.2 dBm. If the current reaches
60 mA before the power reading reaches
-9.2 dBm, the laser source requires repair.
4-6. With the laser source set to 1550 nm, verify
that the power reading is -9.2 dBm ±0.1 dB.
4-7. Adjust the 1550 nm external potentiometer
(R31) counterclockwise to verify that the
laser source output is adjustable to -11.2 dBm
±0.1 dB.
4-8. Adjust R31 until the laser source output reads
-10.0 dBm ± 0.1 dB.
Step 5: Adjusting the 2 kHz Modulated Signal
5-1. Connect an oscilloscope across TP1 and TP2
(Gnd).
5-2. Set the laser source
MOD position. Set the 1550/1310 switch to
CW/MOD switch to the
1310.
5-3. Verify that the signal frequency is 2 kHz
±100 Hz with a duty cycle of 50% ±5%.
Adjust R29 as necessary.
5-4. Set the 1550/1310 switch to 1550 and reverify
signal frequency is 2 kHz ±100 Hz with a
duty cycle of 50% ±5%.
Step 6: Reassembly and Final Test
6-1. Remove the singlemode cable from the laser
source. Put the dust cap onto the laser source
optical ST connector.
6-2. Apply insulating varnish, such as red GLPT,
to all potentiometers adjusted.
6-3. Put the board back in the case. Put the case
halves together and install the four Phillips
screws. Reinstall the lock washers and nuts to
the CW/MOD and 1550/1310 switches.
Install a 9 V battery and the battery door.
6-4. Run the performance tests as described in the
earlier section "Performance Tests".
9
LS-1310/1550
Laser Source
Parts and Accessories
Tables 2 and 3 show the replacement parts and
accessories available from Fluke for the
LS-1310/1550 Laser Source.
Table 2. Replacement Parts
Fluke Part
Description
Battery cover assembly 662632
Top case 625837
Bottom case 625829
Fiber optic cable assembly, ST/ST,
singlemode
Fiber optic adapter, ST/ST, singlemode 625928
9 V battery 614487
LS-1310/1550 Laser Source Instruction
Sheet
Number
662368
687290
Table 3. Accessories
Description
Fiber optic cable assembly, ST/ST,
singlemode
Fiber optic cable assembly, ST/SC,
singlemode
Fiber optic cable assembly, ST/FC,
singlemode
Fiber optic adapter, ST/ST,
singlemode
Fluke Model
Number
NF100SM
NF110SM
NF120SM
NF300SM
10
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