Home FAQs


  What is typical lead time for your products?

QPhotonics maintains a large inventory which allows us to ship most of our products within 1-2 days of receipt of purchase order. In event that we are out of stock the lead time typically varies between 4 to 8 weeks. Lead time for special orders and non-standard wavelengths is between 6 to 8 weeks .


Can I purchase a device at specific wavelength?

Yes, we offer wavelength selection or selecting diode with other criteria from our inventory for an additional fee of $30-$200 per device depending on the selection requirements.


Can I select the device prior to placing the purchase order?

Yes, for an additional fee of $75 per device we will send you device datasheets from which you can select the devices that you want to purchase.


What do I need to operate the device?

Commercially available laser diode driver or laser diode controller with temperature controller is required to operate models QLD, QFLD, QFBGLD, QSDM, QLDM, QBTF and QOFP. For example:

  • QPhotonics SuperDIL laser diode controller
  • Thorlabs model ITC 510
  • ILX Lightwave model LDC-3724B or similar
  • Newport model 6505 or similar

Devices with in-built TEC (models QFLD, fiber coupled QSDM, QFBGLD, QLDM, QBTF) must be operated with TEC controller. For example:

  • Thorlabs TED200
  • ILX Lightwave model LDT-5412 or LDT-5525
  • Newport model 325

Devices without in-built TEC (models QLD, free-space QSDM, QOFP) must be operated using temperature controlled mount. For example:

  • Thorlabs TCLDM9
  • ILX Lightwave model LDM-4407 or LDM-4412
  • Newport model 700-9-5.6

TEC controller is required to operate the mount. PUMA modules have an in-built laser driver. An air-cooled radiator (thermal resistance < 0.120C/W) is required to dissipate heat from the module. A stabilized DC power supply (15 V, 6A) is required to operate PUMA modules. Turn-Key HBS systems do not require any external equipment for operation. Power: AC 120/230 V ( 50/60 Hz ).


Can I operate the device in pulsed mode?

Yes, the devices can be operated in pulsed mode. Typical rise and fall times for models QLD, QFLD are 0.5ns and for models QFLED, QSDM are 12.5ns. For PUMA modules typical rise and fall times are 0.1ms and 0.01ms respectively.


Does SuperDIL laser diode controller support modulation?

No, current version of SuperDIL laser diode controller is designed for continuous wave (CW) operation.


What is the life time of your devices?

QPhotonics carries semiconductor light emitting devices from several manufacturers. Their life time depends on wavelength, power and operating conditions.

For models QLD, QFLD, QFGBLD typical Mean Time to Failure (MTTF) varies between 10,000 hours for QLD-808-100S (100mW @ 808nm) and 250,000 hours for QLD-1550-150S (150mW @ 1550nm)

For model QLDM and PUMA modules typical Mean Time to Failure is at least 50,000 hours at 808 nm and at least 100,000 hours at longer wavelengths.


Can you manufacture non-standard devices as per my requirements?

Yes, we work closely with our manufacturers and customers to deliver custom ordered devices. Please contact us with details regarding your special requirements.


There is no light from the laser/ superluminescent/ light emitting diode, what is wrong with my device?

If there is absolutely no light coming out of your device the most likely reason could be that it is not properly connected. Please refer to the enclosed datasheet to determine pin configuration of the device. Make sure that electrical configuration of the mount you are using corresponds to the device pin configuration. Please refer to the instruction manual of your mount for specifics regarding changing the electrical configuration.

There should be a proper electrical contact between the device pins and the mount socket. Gently push / adjust the device to ensure that the device pins are uniformly engaged in the socket. Turn the socket lever to locked position and/or place the laser clamp over the device package, whichever is applicable.

Operating the device with wrong electrical configuration, even momentarily, can cause permanent irreversible damage to the device.

In the case of fiber-coupled (pig-tailed) device if there is still no light, the reason could be that the fiber/connector is broken. Glass fiber is fragile and requires very careful handling. If your device has an in-built photo-diode, check if there is any photo-diode current by driving the device at a low operating current (10% of the rated operating current IOP). If there is some photo-diode current you can be certain that the fiber is broken. QPhotonics may be able to repair the broken fiber/connector for a fee. Please contact us for details.


My device does not perform according the specifications, why?

Devices are extensively tested and are subjected to stringent selection criteria at our facility. They are carefully packaged in specially designed static-shielded boxes for shipment. Each device is shipped with a complete datasheet generated in our testing facility. Some of the most common reasons for the device to perform below specifications are listed below:

Semiconductor light emitting devices are extremely sensitive to static electricity and surge current. These may cause instantaneous breakdown of the device and/or degradation of optical parameters (power, spectrum, far field).

Operating the device in excess of 10% of rated operational parameters, even momentarily, can cause instantaneous damage to the device resulting in performance deterioration. It is required that the device is driven using commercially available laser diode controllers such as:

  • QPhotonics SuperDIL laser diode controller
  • Thorlabs model ITC 510
  • ILX Lightwave model LDC-3724B or similar
  • Newport model 6505 or similar

Device operating characteristics are function of temperature and the performance deteriorates rapidly at higher temperatures. It is required that the device temperature is controlled using TEC controller for devices with in-built TEC. Devices without in-built TEC must be operated with temperature controlled mount

For details regarding handling and operating the device please refer to ‘PRECAUTIONS’ note that was enclosed with your device.