FAQ

Whether there are any technical issues concerning our products or any general questions, we are always willing to answer them as fast as possible via email or phone. In order to save both our and our clients time, we have provided a list of frequently asked questions.

• Q: What type of power supply should I use?

A: It should be 5V output power and 4 A current for DPSS lasers and 1 A for diode lasers. We highly recommend using the same power supply as we offer on our website. Otherwise, we cannot ensure that the laser would work the same as it was tested during production. Note: Some lasers can draw a little more current at the moment of turn-on, compared to specified.

• Q: How should I cool Matchbox®?

A: Diode laser typically requires 5 W heat dissipation so basically such laser could be cooled when attached to any optical table or cooling device (AM-H4/AM-H7/AM-H8)
DPSS laser typically requires 15 W heat dissipation so such laser should be cooled using our air-cooled heatsink (AM-H3) or TEC cooler (AM-H9) .

• Q: Power has dropped drastically. What happened?

A: There might be several reasons: the laser overheating, the power supply is not sufficient, the laser diode or pump diode has failed. Please check if heat dissipation is sufficient. Launch the laser control software, check whether the TEC is not operating at 100% capacity. What is the voltage between +5 Vcc and GND pins? It should be not less than 4.9 V and not exceed 5.5 V. In case the voltage is different, wires might be too long or too thin or other components are involved that might cause voltage drop/increase.

• Q: How to be sure that laser gets enough cooling?

A: During production, our lasers are tested on a large aluminum breadboard - this is one example of how to dissipate heat. Keep in mind that steel has very poor thermal conductivity, therefore conventional optical tables and breadboards are not suitable for heatsinking of DPSS lasers. Customer should always use thermal grease when mounting the laser. Body temperature of the laser should not exceed about 35°C, and the TEC load should not exceed 80%, with rare exceptions. Diode laser needs no more than 7,5 W heat dissipation. DPSS lasers usually require more – about 15 W heat dissipation. All diode lasers and a majority of DPSS lasers in the MatchBox® series could work properly attached to our forced air cooler.

• Q: What accessories are needed in order to use the Matchbox laser?

A: The MatchBox® series is designed for OEM applications. Integrators can install the laser without any other accessories, just by providing 5 V power and UART control signals to corresponding pins on the back of the laser. However for quick setup, a Breakout-Box or a breakout cable is a good help to start the laser and connect it to a PC via USB. Breakout-Box and a standard USB cable are not included in the laser package. Also power supply and AC power cable are necessary. You should have in mind that the power supply should be ordered separately and that power cable is not included in the package with the power supply.

• Q: What is the Breakout-Box?

A: Breakout-box includes a small printed circuit board attachable directly to the pins of the laser. This electronics board features a USB power socket (optionally, a soldered DC power cable), an RF connector for TTL signal, a fan control socket. Furthermore, it incorporates a UART-to-USB converter chip (SiLabs) and a micro USB socket for remote control.

• Q: I changed the laser power in the control software, but after restart of the system the new power setting was not saved ?

A: New parameters are not saved in the microcontroller of the laser unless 'Save settings’ in the right bottom corner of the main MatchBox software window is activated. This is done to save EPROM write resource.

• Q: What fiber core diameter do you use ?

A: We use fibers from many different vendors. Whether you need to know the actual fiber details, please contact us in order to get detailed information, such as core diameter or NA of the fiber.

• Q: When do I have to use FC/PC and FC/ APC fiber connectors?

A: We recommend to use FC/APC for SLM lasers - this is to avoid back-reflections from a polished fiber tip to the laser cavity. In all other cases, both FC/PC or FC/APC connectors can be used, depending on the users preference.

• Q: Should I ensure grounding for the laser?

A: We recommend that the laser would be mounted to a breadboard that is properly grounded. Electrical socket where power supply is connected must be grounded too. We sell power supplies having grounded pin only.

• Q: Can I modulate the laser with the PWM square wave?

A: In general, yes. However, the bandwidth of PWM depends on the laser type and pinout configuration. For example, by default, DPSS lasers are configured for fan control instead of TTL modulation. It can still be PWM controlled by sending commands over the UART interface with up to 1kHz bandwidth. Direct diode lasers are typically configured for fast (up to 10MHz in ACC mode) modulation instead of fan control, thus PWM with a bandwidth of 10MHz is possible.

• Q: Do I get a replacement if the laser is broken?

A: Lasers within the warranty period are repaired or replaced free-of-charge. Warranty becomes obsolete in cases indicated in the chapter ‘Warranty’.

• Q: I have ordered an SLM laser, but can observe more than one longitudinal mode. How can I solve this problem ?

A: It is possible that the laser is working at a non-optimal temperature point. The first step is to make sure if the laser gets enough heat dissipation. The second step is to adjust laser diode (or cavity) temperature using the laser control software. For this access level 2 or level 3 is needed. Please contact Integrated Optics, UAB for further instructions.

• Q: Laser is working, but its body is very hot.

A: First of all it means that laser diode should be fine, but it could be that heat dissipation is not sufficient. You should check how much Amperes does the laser consume. It should be no more than 1,5 A for diode lasers and no more 4 A for DPSS lasers.

• Q: Laser emits no light at all. The power is 0 mW.

A: Firstly. internal coldplate of the laser could be more than 45 C temperature. Second option is that laser fiber could be not fully straightened up or even damaged. You should check for any damages on the fiber itself or its connector. Recommendations: Before turning the laser on, proper cooling of the laser should be ensured. The laser should be mounted using thermal grease and the screws that were provided with the laser. Please make sure that thermal grease is put very evenly and covers the whole bottom of the laser. If a laser is fiber coupled, the fiber should be carefully straightened up first.

• Q: Is there a recommended way to improve the Diode laser's longevity?
A: Cold start is one of the factors reducing the lifetime of laser diodes, especially pump laser diodes in DPSS lasers. 'Warm laser' is the best mode for a stand-by operation to improve the longevity of the laser diode or the pump diode.

• Q: How to send laser to a warm-up state?
A: There are two ways to send the laser to warm-up state, or in general to control laser: using our software. There is simply a button, that says ‘Auto Warm-up’ or sending commands via terminal. The command is: ‘e 2’.

• Q: What command must be sent to read MatchBox® CW laser input voltage?
A: To read the input voltage “r_r” command must be used. The information it returns is explained in the command table in User’s manual.

• Q: Is AM-H8 cooler suitable with DPSS lasers?
A: Unfortunately DPSS lasers require a better cooling system. The most suitable coolers, in this case, would be AM-H9 or AM-H3.

• Q: Turned on laser voltages are below nominal 4.9V to 5.5V mentioned in the laser specs., is there something wrong with the laser?
A: If the laser works, the voltage isn’t below 3.5V which is the minimum voltage for the internal microprocessor to operate, doesn’t overheat and cools itself, then the voltage drop can be not taken into consideration.

• Q: Our laser has Firmware version of 1.76483. Is there a later version of the firmware and can  it be upgraded?
A: Updating firmware is highly not recommended, because if in any case power source would disconnect or get damaged while updating, laser would be instantly damaged and would have to be sent to Integrated Optics, UAB for repair. So laser firmware can only be updated in particular situations after consulting with the support team at Integrated Optics, UAB.

• Q: After a while of working, laser power dropped by a few mW, why is that?
A: There could be a few reasons why the laser power might drop by a few mW:

   1. The laser is getting some back-reflections and these are having impact on the internal photodiode response. The photodiode ‘sees’ more light and triggers the driving electronics to reduce LD current.

   2. The environmental temperature changed significantly and the internal photodiode isn’t perfectly thermally stabilized and its temperature has changed as did the quantum efficiency of the laser.

   3. The wavelength of the laser diode drifted. If it is on the slope of efficiency of the photodiode, then wavelength change of hundreds of picometers can change the response of the photodiode. Please, adjust the DAC value to restore the power level. If the power of the laser was calibrated, you might want to recalibrate it.

    4. The power sensor of the power measurement degraded.
    5. The power sensor got saturated. Please, check the parameters of the power sensor.

    In cases 1 to 3 it should be visible in the software window that the LD current decreased upon decrease of the laser power.

• Q: Is there a way to change the polarization direction of MatchBox® lasers?
A: You can change the polarization direction by turning the laser body by a desired angle or using optical devices like quartz polarization rotator, waveplate/2. We should note that different types of MatchBox lasers have different polarization directions, but two of the same type lasers of MatchBox’es must have the same polarization!

• Q: How hard should I screw the laser?

A: Recommended Tightening torque is 0.25 - 0.35 N·m.