THORLABS S5FC Series User manual

S5FC Series Single
Channel Fiber-Coupled
SLD Sources
Operating Manual

Fiber Coupled SLD Source
Table of Contents
Chapter 1 Warning Symbol Definitions ..........................................................................................1
Chapter 2 Safety................................................................................................................................2
Chapter 3 Description.......................................................................................................................3
Chapter 4 Setup ................................................................................................................................4
4.1. Setting the AC Line Voltage...........................................................................................4
4.2. Changing the Fuse..........................................................................................................4
4.3. Initial Set-up.....................................................................................................................4
Chapter 5 Operation .........................................................................................................................5
5.1. Front and Back Panel Overview.....................................................................................5
5.2. Turning On the Source ...................................................................................................6
5.3. Viewing Information........................................................................................................6
5.4. Adjusting the SLD Output Power and Temperature ....................................................6
5.5. Turning the SLD Off........................................................................................................7
5.6. Modulating the SLD Output............................................................................................7
Chapter 6 Making the Safety Interlock Connections.....................................................................9
Chapter 7 Remote Communications.............................................................................................10
7.1. Installing the USB Drivers............................................................................................10
7.2. Command Line Interface ..............................................................................................10
7.3. Keywords (Commands and Queries) ..........................................................................11
Chapter 8 Troubleshooting............................................................................................................12
Chapter 9 General Maintenance....................................................................................................13
9.1. Cleaning.........................................................................................................................13
9.2. Connector Cleaning......................................................................................................13
Chapter 10 Specifications................................................................................................................14
Chapter 11 Mechanical Drawing......................................................................................................16
Chapter 12 Regulatory......................................................................................................................17
12.1. Waste Treatment is Your Own Responsibility............................................................17
12.2. Ecological Background ................................................................................................17
Chapter 13 Thorlabs Worldwide Contacts......................................................................................18

Fiber Coupled SLD Source Chapter 1: Warning Symbol Definitions
Rev K, October 31, 2017 Page 1
Chapter 1 Warning Symbol Definitions
Note: Throughout this manual, references to temperature are with respect to °C.
Below is a list of warning symbols you may encounter in this manual or on your device.
Symbol Description
Direct Current
Alternating Current
Both Direct and Alternating Current
Earth Ground Terminal
Protective Conductor Terminal
Frame or Chassis Terminal
Equipotentiality
On (Supply)
Off (Supply)
In Position of a Bi-Stable Push Control
Out Position of a Bi-Stable Push Control
Caution: Risk of Electric Shock
Caution: Hot Surface
Caution: Risk of Danger
Warning: Laser Radiation
Caution: Spinning Blades May Cause Harm

Fiber Coupled SLD Source Chapter 2: Safety
Page 2 19844-D02
Chapter 2 Safety
All statements regarding safety of operation and technical data in this instruction manual will only apply when the
unit is operated correctly.
SHOCK WARNING
High voltage inside. To avoid electrical shock, before powering unit, make sure that the protective
conductor of the 3-conductor power cord is correctly connected to the protective earth contact of
the socket outlet. Improper grounding can cause electric shock resulting in severe injury or even
death. Do not operate without cover installed.
WARNING
This unit must not be operated in explosive environment.
WARNING
Avoid Exposure – Radiation Emitted from apertures.
The unit is supplied with a 115 V parallel blade line cord for North American use only. For all other applications
use an IEC 320 compatible line cord fitted with a plug appropriate for your particular AC wall socket.
Make sure that the line voltage ratin g marked o n the r ear panel agrees with your local supply an d that the
appropriate fuses are installed. Changing of the mai ns fuse can be done by the user (see Setting the AC Lin e
Voltage and Installing Fuses). With the exception of the mains fuses, there are no user serviceable parts in this
product.
Do not operate in wet or damp conditions. Do not obstruct the air-ventilation slots in the housing!
This device can only be returned when packed into the complete original packaging, including all foam-packing
inserts. If necessary, ask for a replacement package.
Mobile telephones, cellular phones or other radio tra nsmitters should not to be used within the range of three
meters of this unit since the electromagnetic field intensity may exceed the maximum allowed disturbance values
according to EN50082-1.

Fiber Coupled SLD Source Chapter 3: Description
Rev K, October 31, 2017 Page 3
Chapter 3 Description
The Thorlabs Fiber Coupled SLD Sources provide easy coupling and simple control of Superluminescent Diode
(SLD) driven fiber optics. Each system is equipped with a single fiber output and is available in 1050 nm, 1310
nm, and 1550 nm center wavelength. The benchtop unit for the 1050 nm SLD has a polarization-maintaining (PM)
fiber output, while units containing an SLD with a 1310 nm and 1550 nm center wavelength are offered with either
single mode (SM) or PM fiber.
Superluminescent Diodes are excellent high power broadband light sources for use as ASE Light Sources and in
applications like Optical Coherence Tomography (OCT) Imaging Systems and Fiber Optic Gyroscopes (FOG).
The SLDs offered here are indium phosphide (InP) devices manufactured by Thorlabs' Quantum Electronics
Division.
The SLD operates from an independent, high-precision, low-noise, constant-current source and temperature
control unit. An intuitive LCD interface allows the user to view and set the parameters for the SLD. T he user can
adjust the S LD current and temperature control independently. The display indicates th e model type, output
wavelength of the source, the operating power calculated from the SLD monitor diode, and the actual temperature
the SLD is set to.
This device includes a mic rocontroller to fully control the SLDs optical power, temperature, and monitor the
system for fault conditions. The S5FC source includes a USB connection that allows remote adjustment of power,
temperature, and enabling. On the rear panel, an analog input is available to modulate the SLD with an external
signal. This is added to the internal set point. To prevent damage, the microcontroller will disable the output if the
analog input plus the internal set point exceeds the SLD limits.
For added safety, there is an interlock located on the rear panel that must be shorted in order for any SLD output
to be enabled. This can easily be configured to be triggered by doors to disable the SLD in unsafe conditions. The
power switch is a key-lo ck system to prevent accidental or unwanted use. An enabl e button must b e set to
activate the unit with a green LED indicator to easily determine its current state. There is a 3 second delay before
the SLD turns on, and the user is warned by the rapidly blinking LED.
The S5FC includes a universal power supply allowing operation over 100 to 240 VAC without the need for
selecting the line voltage. This unit is supplied with a US line cord as well as a standard European line cord. The
fuse access is conveniently located on the rear panel.

Fiber Coupled SLD Source Chapter 4: Setup
Page 4 19844-D02
Chapter 4 Setup
4.1. Setting the AC Line Voltage
The S5FC Series SLD Source has been shipped configured for 100 to 240 VAC operation. There is no end user
adjustment of the line voltage for 110 or 220 VAC. The user needs to select the correct AC cord for their location.
4.2. Changing the Fuse
To change the power fuse, follow the following steps.
1. Remove the AC power cord if it is connected to the unit.
2. Locate the fuse tray directly below the AC power cord connection on the rear panel of the unit.
3. Carefully use a flat blade screwdriver to open the fuse tray.
4. Remove the existing fuse and install the appropriate 500 mA fuse. The replacement fuse must be a 5 mm
x 20 mm, 250 VAC Type T Fuses (IEC 60127-2/III, low breaking capacity, slow blow)
5. Push the fuse tray back into place making sure that it snaps and seats correctly.
6. Connect the appropriate power cord into the AC receptacle and plug the unit in.
4.3. Initial Set-up
1. Set the unit on a dry, level working surface.
2. Make sure the POWER key switch on the front of the unit is in the OFF po sition (key perpendicular to
working surface).
3. Plug the female end of the AC line cord provided into the AC In put Receptacle on the rear of the unit.
Plug the male end into a properly grounded AC socket.
4. Install the interlock “shorting device” into the interlock connector located on the rear panel. See page 9 for
details.
5. Connect a FC/APC Fiber Optic cable to the SLD output connector on the front panel of the unit.

Fiber Coupled SLD Source Chapter 5: Operation
Rev K, October 31, 2017 Page 5
Chapter 5 Operation
5.1. Front and Back Panel Overview
Figure 1 Front and Rear Panels of SLD Source
Digit Display with Backlight
Displays channel, output power,
wavelength, and temperature.
SLD Output Port
FC/APC fiber optic connecto
r
SLD Enable Switch
Press to activate.
SLD Emission Indicato
r
Indicates activation. It will blink for
3 seconds prior to the SLD turning on.
Keylock Power Switch
Key only removes when off
Control Knob/Switch
Selects channel, adjusts current
and temperature.
Remote Interlock Inpu
t
(See page 9 for details)
USB Input Connecto
r
Allows full operation
through a PC interface
AC Power Cord
Connector
Modulation Input - 0 to 5 V Max
A
ccepts complex waveforms.
See section 5.6 for details
Fuse Tray
See section 3.1 for replacement details
Fiber Alignment Symbol
Slow Axis (S.A.) is aligned to
connector key (PM Versions Only)
Cooling Fan - Do Not Block
Periodically remove dust buildup
from vents for best operation.

Fiber Coupled SLD Source Chapter 5: Operation
Page 6 19844-D02
5.2. Turning On the Source
1. Turn the POWER key switch clockwise. The LCD display will scroll “Thorlabs” across the screen, followed
by the software revision number.
2. Make sure the Interlock Input is short-circuited; see page 9 for detailed instructions.
3. Press and release the ENABLE swit ch to activate the SLD. Ther e will be an approximately 3 second
delay before the SLD powers up. During this time the ENABLE indicator will light up and blink rapidly.
4. SLD power (mW) an d thermo-electric cooler readings will be activated when the unit t urns on. The
temperature will typically require 1 to 2 minutes to stabilize.
5.3. Viewing Information
The S5FC uses a single four quadrant LCD to display and access information. At any time, display varia bles can
be adjusted by simply rotating the control knob located to the left of the display. The following information will be
available:
• Top left – Indicates device type (SLD).
• Top Right – Indicates the wavelength of the SLD internal to the S5FC. This is set at the factory when the
SLDs are installed.
• Bottom Left – If a monitor diode is included in the
SLD package, a power reading in (m W) will be
displayed. When enabled, the current po wer
level determined from the monitor photodiode will
indicate the approximate power level of th e
output. When disabled, the power le vel will read “0.00mW”. If a monitor diode is not included in the SLD
package, a current reading in (mA) will be indicated instead.
Note: The power shown on the display is the optical power at the SLD output connector calibrated to the
monitor photodiode. The actual power at the end of your fiber optic cable may be less, depending on the
quality of the connection. All fiber optic cables installed should be cleaned first since dust and dirt particles in
the connector will effect coupling efficiency and possibly damage the fiber connectors.
• Bottom Right – Indi cates the actual temperature the SLD i s stabilized to and is di splayed in °C. The
system defaults to a temperature of 2 5.00 °C until changed by the user. T he temperature control is
always active and may require 5 to 10 minutes to fully stabilize.
5.4. Adjusting the SLD Output Power and Temperature
Note: The adjustment knob utilizes an intelligent speed control. Adjusting the knob slowly will increment
values at the maximum resolution while adjusting fast will make larger movements. This allows both a fine
and course control.
1. The bottom left location will start blinking and will change to current, ex: xx.xx mA, when the control knob
is pressed. Adjust the control knob until the desired current is a chieved. The first time defaul t setting will
be current full off. Adjusting the knob clockwise will immediately set the current to the SLD threshol d and
then incrementally to the max operating current. Adjusting the knob counter clockwise will incrementally
decrease the current until it hits the thresh old, and then immediately to SLD of f. On system shut down,
the current setting will be remembered.
Note that there is a timeout on the display, after which the display will revert back to the viewing mode. This is
to prevent accidental adjustment of the power.
2. Press the knob again to switch to temperature adjustment. The set poi nt temperature will be displayed
and will be blinking; for example, 25.00 °C. Adjust the control knob to increase or decrease the
temperature set point. The temperature default is 25.00 °C but can be adjusted over a range of 20.00 to
30.00 °C with a resolution of 0.01 °C.

Fiber Coupled SLD Source Chapter 5: Operation
Rev K, October 31, 2017 Page 7
Note, as above there is a timeout where the display will revert to the viewing display and lock out adjustment
to the temperature.
3. Pressing the control knob again will exit the adj ustment mode and revert b ack to the viewin g mode,
locking in the selected parameters. This can also be achieved by allowing the display to time out at any
point in the process. The power display will adjust real-time to its new current setting and depending on
the magnitude of the change in temperature set point, it will take anywhere from a few seconds to a few
minutes for the system to settle into the new operating temperature.
5.5. Turning the SLD Off
• Standby Mode – By adju sting the control knob fully counterclockwise the current/power will adjust down
to the threshold current and then to standby mode. The threshold current is a user settable point at which
the internal SLD diode can be set to op erate within a desirable range. For convenience the system is set
up to adjust from the threshold to the max current. In addition, when adjusting below the threshold, the
current will be set to almost 0 mA. Since the system utilizes a constant current control, there will al ways
be a minimum current to maintain the current control loop. The output emission is typically very low, or
nonexistent. The SLD is still enabled and operating at the minimum possible current. This can be useful
while using the external modulation. The full 5 V can be applied without compensating for the internal set
point. However, the external signal will need to provide a DC offset to bias the SLD above the threshold
current for best results. Input signals will see clipping on their lower edges below threshold.
• Disable/Enable Mode - The SLD output should be turned off by pressing and releasing the ENABL E
switch. The SLD temperature will be maintained even when the SLD is disabled.
• Power Down - When completely powering down an enabled unit, first p ress and release the ENABLE
switch and then turn the POWER key switch co unterclockwise, which will t urn OFF the entire u nit.
Anytime the unit is turned OFF and then turned back ON, the S LD will be disabled until the ENABLE
switch is pressed.
5.6. Modulating the SLD Output
The MOD IN input can b e used to mo dulate the SLD output, or set the SLD output remotely using a 5 V power
source. The 5 V maximum input co rrespond to the maximu m calibrated power, which operates using a constant
current drive technique. The re sulting actual outp ut power is depe ndent on the set cu rrent and op erating
temperature. In addition, i n order to eliminate a dead zone in th e power control knob, the output of the unit is
offset to the threshold current of the coupled SL D diode. Adjusting the knob below threshold will immediately set
the current to almo st 0 mA, or Stand by mode a s described in section 4.5. Therefore, there are two modes of
modulation available. First setting the control to “Sta ndby” allows the analog modulation to utilize the full 0 to 5 V
input range. The drawback is that a minimum voltage will be required to operate above the threshold current but
allows more flexibility by the user. The second mode is to adjust the control knob so that the SLD is at threshold
or above. The analog modulation voltage will be limited to less than 5 V, but a DC offset will not be required. This
should be kept in mind when using the modulation input since it will limit the actual input voltage range.
1. Connect a signal generator or 0 to 5 V power source to the unit using a BNC type connector.
2. Set the PWR ADJ knot on the f ront panel to its f ull counter clockwise setting for sta ndby mode, o r
increase slightly to the threshold current mode.
3. Press the ENABLE switch to turn on the SLD, wait for the safety delay to time out.

Fiber Coupled SLD Source Chapter 5: Operation
Page 8 19844-D02
4. For Threshold Offset - Apply the appropriate signal to the MOD IN input. If too mu ch voltage is applied
internal current limiting will prevent da mage to the SLD diod e and the SLD diode will be immediately
disabled. If a n internal th reshold is set the a cceptable drive voltage range will be le ss than 5 V. To
calibrate your input apply a DC voltage to the MOD IN and slowly increase until the system disables. This
will be the max voltage allowable.
For Standby Operation – Apply a n appropriate signal between 0 and 5 V to the M OD IN input.
Determine the DC offset by increasing the voltage slowly until a large power jump is seen on the output.
An easier method is to apply a 1 Vpp sinusoid and adjust the DC offset until the sinusoid appears and then
the bottom edge is no longer clipping. This method requires applying the SLD output to a photodetector
and monitoring with a n oscilloscope. Next maximi ze the amplitude so that the pe ak is 5 V or less a s
desired.