High-Power Fiber-Coupled Laser Sources: NIR, with TEC

S6FC2000

2000 nm, 15 mW

FC/PC or FC/APC Interface for Single Mode Fiber
High Current TEC for Temperature Regulation and Stability
Software Interface for Computer Control

S4FC1310

1310 nm, 50 mW

Please Wait

Overview
Specs
Temp. Stability
Pin Diagrams
Software
Laser Safety
Feedback

Single Channel Benchtop Laser Sources Selection Guide
Spectrum	Wavelength	TEC	Laser Type	Cavity Type	Output Fiber Type
Visible	405 - 675 nm	No	Semiconductor	Fabry Perot	SM, MM, or PM
Visible	405 - 685 nm	Yes	Semiconductor	Fabry Perot	SM
NIR	785 - 1550 nm	No	Semiconductor	Fabry Perot	SM or PM
	705 - 2000 nm	Yes	Semiconductor	Fabry Perot	SM
	1310 - 1550 nm	Yes	Semiconductor	DFB	SM
	1900 - 2000 nm	N/A	Fiber Laser	Fabry Perot	SM
MIR	2.7 µm	N/A	Fiber Laser	Fabry Perot	SM
Other Fiber-Coupled Laser Sources

Click to Enlarge
An illustration of the difference in the intensity noise floor between our S3FC series standard FP laser sources with TEC and our S4FC series high-power FP laser sources with TEC. The noise signal from the S4FC laser shows a considerable reduction in the peak-to-peak noise amplitude, as well as suppression of high frequency components that are seen in the noise signal of the S3FC laser. The S3FC plot is vertically offset in order to better compare the two signals. Note that the curves shown are without mode-hopping, which will occur despite temperature or current adjustment.

Features

NIR Wavelengths Available from 705 to 2000 nm
Single Mode, FC/PC or FC/APC Fiber Interface
Typical Maximum Output Powers up to 100 mW
High-Current TEC for Temperature Regulation and Stability
BNC Connector for Modulating Output with Analog Input
USB Connector for Computer Control via Included GUI or Command Line
Power Level is Adjustable via Knob and BNC Modulation Input
Constant Current Operation
Interlock Circuit Provided via 2.5 mm Mono Jack

Thorlabs' NIR High-Power Fiber-Coupled Laser Sources are high-performance benchtop Fabry-Perot laser diode sources with TEC, which offer excellent stability and computer control. The internal electronics isolate the laser diode driver from noise coupling (such as that produced by nearby switching supplies). As a result, these high-power FP laser sources with TEC offer lower noise intensity compared to our standard FP sources with TEC (see graph to the right). The integrated, high-current TEC element can provide excellent temperature regulation and stability to the laser diode, as illustrated in the graphs on the Temp. Stability tab. Even when the ambient temperature changes significantly, the temperature control servo is capable of maintaining constant temperature at the laser diode head. This exceptional temperature stability produces a constant and stable power output from the device.

Click to Enlarge
An example of the S4FC series software GUI. Both the S4FC series and S6FC2000 high-power laser sources include software packages. See the Software tab above for details.

For both the S4FC series and S6FC2000 laser sources, the laser diode is pigtailed to a single mode fiber. In the S4FC series sources, the fiber is terminated at an FC/PC bulkhead connector (wide and narrow key compatible). In the S6FC2000 source, the fiber is terminated at an FC/APC fiber connector (wide and narrow key compatible). The S6FC2000 features an angled fiber ferrule at the internal laser/fiber launch point to minimize reflections back into the laser diode, thereby increasing the stability of the laser diode's output. To minimize losses, we recommend using a fiber patch cable that is the same fiber type as the fiber-pigtailed laser.

These laser sources operate via constant current. The power is displayed on the S4FC sources, whereas the current is displayed on the S6FC2000 source. Also on the display panel is the temperature in °C, an on/off key, an enable button, a knob to adjust either the laser power (S4FC series) or the laser current (S6FC2000), and a trimpot to adjust the temperature (TEC current).

The back panel includes a BNC input that allows the laser diode drive current to be controlled via an external voltage source (0 - 5 V) and a remote interlock input. This input enables intensity modulation of the laser source. Using a sine wave, the output can obtain full-depth modulation at frequencies up to 100 kHz. A USB connector on the back panel enables computer communication. The included GUI provides control and readout of the laser's output power and setpoints (see Software tab). The back panel also features a remote interlock input (2.5 mm mono jack) for added safety.

Note that the fiber bulkhead and patch cable ferrule must be cleaned prior to connecting a patch cable. For instructions, please refer to the operating manual. The laser must be off when connecting or disconnecting fibers from the device, particularly for power levels above 10 mW. For applications that require several laser sources, consider the temperature-stabilized four-channel fiber coupled laser source.

Common Specifications
Driver
Display Accuracy		±5% of Actual
S4FC Series Laser Adjustment Range	Default	Laser Threshold to Max
S4FC Series Laser Adjustment Range	Option	0 mA Current to Max
S6FC2000 Laser Adjustment Range	Default	Laser Threshold to Max or Min
S6FC2000 Laser Adjustment Range	Option	0 mA Current to Max or Jumps to Min
Laser Adjustment Resolution^a		S4FC Series: 0.01 mW S6FC2000: 0.1 mA
Temperature Adjustment Range		20 °C to 30 °C
Temperature Setpoint Resolution		0.01 °C
Modulation Input^b		0 to 5 V (0 to Full Power)
Modulation Input Impedance		1 kΩ
Modulation Input Connector^c		BNC
Modulation Bandwidth^d		≤100 kHz, Sine Wave
General
Output Fiber Connector		FC/PC or FC/APC^e, 2.2 mm Wide-Key Slot
Operating Temperature		15 to 35 °C
Storage Temperature		0 to 50 °C
Input Power		85 - 264 VAC; 50 - 60 Hz
USB Connector^c		Type B

While Laser is Enabled
Modulation Input voltage directly corresponds to output power, where 5 V = Max Power and 0 V = 0 mW when the front panel knob is set to 0 mW. The maximum voltage will be less than 5 V when using the default laser adjustment range (Laser Threshold to Max).
The maximum USB and BNC cable length is 3 meters in order to avoid a susceptibility to RF interference according to IEC61000-4-3.
Waveforms other than sine waves contain components with higher frequency than the overall frequency of the waveform, which may not be followed.
Only the S6FC2000 is offered with an FC/APC connector.

Laser Source and Fiber Specifications
Item #	Wavelength	Internal Fiber	Spectrum^a (Click for Graph)	Laser Class	Maximum Output Power^b		Laser Power Stability^c
Item #	Wavelength	Internal Fiber	Spectrum^a (Click for Graph)	Laser Class	Min	Typical	15 min	24 hr
S4FC705^d	705 ± 10 nm	SM600		3B	13 mW	15 mW	≤0.022 dB (≤0.5%)	≤0.087 dB (≤2.0%)
S4FC785^d	785 ± 10 nm	780HP		3B	98 mW	100 mW	≤0.022 dB (≤0.5%)	≤0.087 dB (≤2.0%)
S4FC808^d	808 ± 10 nm	SM800-5.6-125		3B	28 mW	30 mW	≤0.087 dB (≤2.0%)	≤0.087 dB (≤2.0%)
S4FC820^d	820 ± 10 nm			3B	78 mW	80 mW	≤0.022 dB (≤0.5%)	≤0.150 dB (≤3.5%)
S4FC852^d	852 ± 10 nm			3B	28 mW	30 mW	≤0.022 dB (≤0.5%)	≤0.065 dB (≤1.5%)
S4FC915^d	915 ± 10 nm			3B	38 mW	40 mW	≤0.013 dB (≤0.3%)	≤0.022 dB (≤0.5%)
S4FC940^d	940 ± 10 nm			3B	28 mW	30 mW	≤0.022 dB (≤0.5%)	≤0.087 dB (≤2.0%)
S4FC1064^d	1064 ± 10 nm	HI1060		3B	48 mW	50 mW	≤0.087 dB (≤2.0%)	≤0.132 dB (≤3.0%)
S4FC1310	1310 ± 20 nm	SMF-28 Ultra		3R	48 mW	50 mW	≤0.004 dB (≤0.1%)	≤0.009 dB (≤0.2%)
S4FC1550	1550 ± 20 nm	SMF-28 Ultra		3B	48 mW	50 mW	≤0.004 dB (≤0.1%)	≤0.009 dB (≤0.2%)
S6FC2000^d	2000 ± 20 nm	SM2000		1M	10 mW	15 mW	≤0.043 dB (≤1.0%)	≤0.087 dB (≤2.0%)

Spectral plots are typical and actual spectra may vary from lot to lot. Measurements were obtained with an optical spectrum analyzer. For further information, please contact Tech Support.
Specified at Temperature Set Point of 25 °C
At 75% of maximum output power. The stability spec was obtained after a 1 hour warm-up period.
This laser source may experience mode-hopping that cannot be tuned out with temperature or current adjustment. Therefore, power stability should be interpreted as the maximum power drift over that period.

The stability data below was obtained using an S4FC660 Laser Source. The performance is representative of both our S4FC sources and our S6FC2000 source.

Click to Enlarge
A demonstration of the long-term stability of the S4FC660 Laser source, shown over the course of 25 hours. The device is capable of maintaining a constant laser diode temperature, and thus constant output power, over long periods of operation. To obtain the detector signal, the S4FC660 output power was set to 75% of maximum and passed through ND filters reducing the power to 1 mW. The resultant beam was directed into a DET100A (previous generation) detector which was then connected to an oscilloscope via a T-adapter and high-impedance terminator.

Click to Enlarge
The graph above demonstrates the ability of the S4FC660 to maintain steady temperature regulation even with large changes in the environmental temperature. Even when the environment changes by 20 °C, the S4FC660 is able to maintain a steady and regulated temperature of the laser diode, yielding a consistent power output. To obtain the detector signal, the S4FC660 output power was set to 75% of maximum and passed through ND filters reducing the power to 1 mW. The resultant beam was directed into a DET100A (previous generation) detector which was then connected to an oscilloscope via a T-adapter and high-impedance terminator.

Modulation In

BNC Female

0 to 5 V Max, 1 kΩ

Remote Interlock Input

2.5 mm Mono Phono Jack

2.5 mm Phono Jack

Terminals must be shorted either by included plug or user device, i.e. external switch, for laser mode "ON" to be enabled.

USB

USB Type B

Computer Interface

S4FC Software Package

Version 2.0.1

Includes a GUI for control of Thorlabs S4FC Benchtop Laser Sources. To download, click the button below.

S6FC Software Package

Version 1.1.0

Includes a GUI for control of Thorlabs S6FC2000 Benchtop Laser Source. To download, click the button below.

GUI Interface
Each software package allows the user to control the settings and the display features of the benchtop laser source. The Options window in the S4FC software and the Settings tab in the S6FC software include several helpful features for controlling the device, including setting an output limit, starting the device from the last setting (instead of at 0 mW or threshold power), adjusting the device by current, dimming the display intensity, or enabling the temperature LED to blink when the device is not at its temperature setpoint (making it visually easier to observe when the laser is not at thermal equilibrium).

The controls tab can be used to select the temperature setpoint, interlock status, and to enable the laser's output. In the S4FC software, the power of the device can be adjusted and will be displayed when the enable button is activated. In the S6FC2000 software, the current of the device can be adjusted and will be displayed when the enable button is activated.

Click to Enlarge
The control panel of the software when the laser source is connected. An example of the S4FC series GUI is shown.

Click to Enlarge
The Controls tab of the software when the laser source is connected and the laser not yet enabled. An example of the S6FC2000 GUI is shown.

Laser Safety and Classification

Safe practices and proper usage of safety equipment should be taken into consideration when operating lasers. The eye is susceptible to injury, even from very low levels of laser light. Thorlabs offers a range of laser safety accessories that can be used to reduce the risk of accidents or injuries. Laser emission in the visible and near infrared spectral ranges has the greatest potential for retinal injury, as the cornea and lens are transparent to those wavelengths, and the lens can focus the laser energy onto the retina.

Safe Practices and Light Safety Accessories

Laser safety eyewear must be worn whenever working with Class 3 or 4 lasers.
Regardless of laser class, Thorlabs recommends the use of laser safety eyewear whenever working with laser beams with non-negligible powers, since metallic tools such as screwdrivers can accidentally redirect a beam.
Laser goggles designed for specific wavelengths should be clearly available near laser setups to protect the wearer from unintentional laser reflections.
Goggles are marked with the wavelength range over which protection is afforded and the minimum optical density within that range.
Laser Safety Curtains and Laser Safety Fabric shield other parts of the lab from high energy lasers.
Blackout Materials can prevent direct or reflected light from leaving the experimental setup area.
Thorlabs' Enclosure Systems can be used to contain optical setups to isolate or minimize laser hazards.
A fiber-pigtailed laser should always be turned off before connecting it to or disconnecting it from another fiber, especially when the laser is at power levels above 10 mW.
All beams should be terminated at the edge of the table, and laboratory doors should be closed whenever a laser is in use.
Do not place laser beams at eye level.
Carry out experiments on an optical table such that all laser beams travel horizontally.
Remove unnecessary reflective items such as reflective jewelry (e.g., rings, watches, etc.) while working near the beam path.
Be aware that lenses and other optical devices may reflect a portion of the incident beam from the front or rear surface.
Operate a laser at the minimum power necessary for any operation.
If possible, reduce the output power of a laser during alignment procedures.
Use beam shutters and filters to reduce the beam power.
Post appropriate warning signs or labels near laser setups or rooms.
Use a laser sign with a lightbox if operating Class 3R or 4 lasers (i.e., lasers requiring the use of a safety interlock).
Do not use Laser Viewing Cards in place of a proper Beam Trap.

Laser Classification

Lasers are categorized into different classes according to their ability to cause eye and other damage. The International Electrotechnical Commission (IEC) is a global organization that prepares and publishes international standards for all electrical, electronic, and related technologies. The IEC document 60825-1 outlines the safety of laser products. A description of each class of laser is given below:

Class	Description	Warning Label
1	This class of laser is safe under all conditions of normal use, including use with optical instruments for intrabeam viewing. Lasers in this class do not emit radiation at levels that may cause injury during normal operation, and therefore the maximum permissible exposure (MPE) cannot be exceeded. Class 1 lasers can also include enclosed, high-power lasers where exposure to the radiation is not possible without opening or shutting down the laser.
1M	Class 1M lasers are safe except when used in conjunction with optical components such as telescopes and microscopes. Lasers belonging to this class emit large-diameter or divergent beams, and the MPE cannot normally be exceeded unless focusing or imaging optics are used to narrow the beam. However, if the beam is refocused, the hazard may be increased and the class may be changed accordingly.
2	Class 2 lasers, which are limited to 1 mW of visible continuous-wave radiation, are safe because the blink reflex will limit the exposure in the eye to 0.25 seconds. This category only applies to visible radiation (400 - 700 nm).
2M	Because of the blink reflex, this class of laser is classified as safe as long as the beam is not viewed through optical instruments. This laser class also applies to larger-diameter or diverging laser beams.
3R	Class 3R lasers produce visible and invisible light that is hazardous under direct and specular-reflection viewing conditions. Eye injuries may occur if you directly view the beam, especially when using optical instruments. Lasers in this class are considered safe as long as they are handled with restricted beam viewing. The MPE can be exceeded with this class of laser; however, this presents a low risk level to injury. Visible, continuous-wave lasers in this class are limited to 5 mW of output power.
3B	Class 3B lasers are hazardous to the eye if exposed directly. Diffuse reflections are usually not harmful, but may be when using higher-power Class 3B lasers. Safe handling of devices in this class includes wearing protective eyewear where direct viewing of the laser beam may occur. Lasers of this class must be equipped with a key switch and a safety interlock; moreover, laser safety signs should be used, such that the laser cannot be used without the safety light turning on. Laser products with power output near the upper range of Class 3B may also cause skin burns.
4	This class of laser may cause damage to the skin, and also to the eye, even from the viewing of diffuse reflections. These hazards may also apply to indirect or non-specular reflections of the beam, even from apparently matte surfaces. Great care must be taken when handling these lasers. They also represent a fire risk, because they may ignite combustible material. Class 4 lasers must be equipped with a key switch and a safety interlock.
All class 2 lasers (and higher) must display, in addition to the corresponding sign above, this triangular warning sign.

Posted Comments:

user (posted 2023-11-29 04:31:26.86)

Your collimation overview states: "To observe interference fringes, the coherence length of the incident light must be longer than the change in optical path length caused by the shear plate being used. See the Specs tab for the approximate change in optical path length, ΔOPL, for each shear plate offered here. Broadband sources, such as Superluminescent Diodes (SLDs) and LEDs, will not create interference fringes due to their low coherence lengths." But unless I missed it, I can't find the coherence length listed for any of the fiber coupled laser sources. Please help.

ksosnowski (posted 2023-11-29 02:17:22.0)

Thanks for reaching out to Thorlabs. On the Specs tab you can view the sample spectra for these lasers. The S4FC series uses fabry-perot emitters. These spectra are not Lorentzian, but rather a set of discrete narrow peaks corresponding to the cavity modes. When you look at the interferogram of such a laser, you would see beating effects between the modes, which makes it not-so-straightforward to determine its coherence length. Due to this, the typical coherence is much shorter than expected if taking a rough estimate of the spectral width from our plots. A laser with external cavity like DFB or VHG will have a much narrower spectrum and better coherence.

Filip Milojkovic (posted 2022-10-27 16:01:34.283)

Hi does S4FC852 have an integrated optical isolator? I can't see it in the specifications. Thanks in advance

ksosnowski (posted 2022-10-27 04:51:53.0)

Thanks for reaching out to Thorlabs. The S4FC series do not include an internal isolator on the output port.

Tahseen Kamal (posted 2019-12-03 10:39:49.89)

Hi, I encountered some issues while trying to use the GUI. As there is minimal instructions on the software, I am unsure how to handle them. If you could help would be great. 1. I tried using my Dell laptop which has Windows 10 pro installed. The software kept crashing. 2. Then I used another PC with windows 7 and the GUI worked. But there was communication delays I guess. It happened that I changed the power quickly and then the device went to lock mode despite the GUI showing the Lock was "off". 3. Also, when I changed the power and the beam looked brighter on the card, the GUI was showing 0 mW as power on the top right display. Hope to get some support on this. Thanks.

asundararaj (posted 2019-12-05 01:57:24.0)

Thank you for contacting Thorlabs. I have reached out to you directly to troubleshoot this further.

Ben Garber (posted 2019-05-22 13:31:58.193)

If there's a specific intermediate wavelength we need (e.g. 813nm), can you provide a laser of one of the existing models that can provide that?

YLohia (posted 2019-05-23 08:32:10.0)

Hello, thank you for contacting Thorlabs. Custom items can be requested by clicking the "Request Quote" button above. I have reached out to you directly to discuss the possibility of offering this.

user (posted 2018-11-02 11:13:13.69)

Sorry, can you tell me the noise current of the source:S4FC785?

YLohia (posted 2018-11-05 09:43:29.0)

Hello, thank you for contacting Thorlabs. The noise current measurement for the S4FC785 is 7.92 uA.

user (posted 2018-10-30 12:25:02.19)

What is the 'a.u.' in the diagram Noise Comparison meaning?

mmcclure (posted 2018-10-30 09:12:56.0)

Hello, thank you for your inquiry. "a.u." is an abbreviation of "arbitrary units".