Home How to Operate QPhotonics Laser Diode

How to Operate QPhotonics Laser Diode


I. Safety

This Laser/Superluminiscent diode emits visible/invisible electromagnetic radiation which may be harmful to eyes and/or skin. The intensity of the radiation may be sufficient to cause instantaneous and permanent damage to retina of the eye. Avoid watching output light from the diode directly (or through collimating optics) or indirectly after reflection from smooth surfaces. For viewing the invisible laser beam use of infrared camera or Infrared card is recommended.

Class 3b Laser


Refer to ANSI-Z-136.1 (1986) and CFR 1040.10 -1040.11 standards for requirements and recommendations for the safe use of lasers.

II. Static Electricity or Surge Current

Laser diode can be adversely affected by static electricity and/or surge current. This may cause the breakdown of the device and/or reduction in reliability. Following precautions are strongly recommended while handling the device:

  1. Body of the personnel handling the device should be static protected by use of earth-band or like and grounded. Clothes, hats, shoes etc of the personnel must also be static protected when in use.
  2. Soldering Iron if used should be grounded to protect the diode from voltage leak.
  3. Power supply, measurement instruments and installations should be grounded as well.
  4. Use of commercially available laser diode drivers or laser diode controllers with temperature controller is strongly recommended to operate laser/Superluminiscent diodes. Otherwise use of a regulated power supply, current limiting resistor and negative surge absorbing diode is required.
  5. Use of common DC power supplies is not recommended as it may generate destructive current surges when it is switched ON and OFF. Current level must be zero before switching the supply ON or OFF.

III. Absolute Maximum Ratings

Do NOT exceed, even momentarily, the maximum ratings. Driving the laser diode in excess of 10% of the rated operational parameters (Iop, Vop, Pop) may cause instantaneous breakdown, performance deterioration and reduction in lifetime. Check the transient characteristics of the power supply to make sure that the surge currents generated during ON/OFF operations do not exceed the maximum ratings.

IV. Temperature

Laser diode operating characteristics vary with temperature. Reliability of the laser diode falls exponentially at higher temperatures. Never allow the case to exceed the maximum operating temperature (TOP MAX = 50 degrees C, unless specified otherwise). The device must be mounted on a heatsink made of high thermal conducting metal like aluminum, copper etc. Radiant area of the heatsink must be at least 100 cm2 unless specified otherwise.

Laser diodes in 14pin DIL and Butterfly packages have an in-built peltier TEC (thermoelectric cooler) and NTC Thermistor. In addition to the heatsink, an external TEC controller should be used to maintain a stable operating temperature. TEC temperature must be stabilized (T=25 degrees C, unless specified otherwise) before turning ‘ON’ the laser diode. Make sure that controller maintains the set temperature throughout the operation of the device.

V. Package Handling

  1. Package must not be opened, reworked, or damaged.
  2. In the case of free-space laser diodes (9mm, 5.6mm can package), do not hold the cap of the laser diode tight as it may cause cracks in the window glass. Do not touch the surface of the window glass. Any scratch or contamination may result in reduction of optical characteristics. Minor surface contaminations may be cleaned softly using cotton with small amount of methyl alcohol or acetone.
  3. In the case of fiber coupled laser diodes the fiber pigtail should be handled very carefully. Do not twist, pull or bend the fiber. If the pigtail is connectorized, clean the connector regularly using standard industry equipment. Do not operate the device without removing the connector cap. Make sure to replace the connector cap after each use.
  4. While mounting the device on a heatsink block using screws, do not use torque greater than 1.5 kg.f.cm.
  5. Device may be soldered into a circuit only after proper mounting of the header to an appropriate heatsink. Soldering time should be less than 10 seconds at below 260 degrees C (Case Temperature < 25 degrees C)