The patented circuitry of our QCL Driver has been integrated into several applications where low noise is key to achieving new detection thresholds. For example, Aerodyne found “a significant improvement in the performance of our [trace gas sensor] instruments over the last five years, with much of the improvement due to reduced noise power supplies and laser drivers. The instrument employs a QC laser current driver manufactured by Wavelength Electronics…. Efforts to reduce electronic noise throughout the system have resulted in exceptional performance”.
Other field deployed gas sensors also reference this technology. If you are still wondering if your application would benefit from low electronic noise, Wavelength has made demonstration units available for you to try in your system. Contact your local distributor or Wavelength’s technical support engineers to arrange a trial.
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At Wavelength, we manufacture all of our products, giving us complete control of the processes to ensure the highest quality. We take Electro-Static Discharge very seriously and have strict ESD protocols to protect the products from any discharge.
In developing our ESD protocol, we found few practical examples, just basic industry guidelines. For example, sticky notes are rarely mentioned, but since they always create static discharge when removed, they cannot be used to label ESD sensitive parts or assemblies.
In our new Electro-Static Discharge Basics application note, we offer the practical examples not found in other ESD Basics white papers.
The PLD family of laser diode drivers has proven to be a reliable workhorse in many industries.
The input voltage specifications on our PLD drivers list a maximum of 30V. With a simple Product Variation (PV044), this value can be increased up to 85V, so higher voltage laser diode stacks can also be powered. It is critical to calculate how much internal power will be dissipated in the PLD at the higher input voltage.
Our technical support engineers can model your application and determine how to best implement these drivers in your system.
Often the photodiode transfer function listed on a laser diode datasheet can be off by over 100%, which can cause a problem with constant power mode operation. If the photodiode produces half the expected current, the drive current can rail to the limit.
We suggest the following process when using a laser diode in constant power mode when the photodiode transfer function is not yet calibrated.
1. Set current limit to a safe level below the maximum current listed on the LD datasheet.
2. Start in Constant Current mode with the setpoint at a typical operating current.
3. Monitor the PDMON signal to see if PD feedback is present (Ideally this will be mid range).
4. If it is not in range, reduce the photodiode feedback resistor (RPD) by half (to RPD / 2). Lower this resistance until the feedback signal is in range.
5. Now calculate the setpoint for constant power mode. Adjust setpoint to this level and shift to Constant Power mode.
6. An optional external power meter can be used to calibrate the PD transfer function.
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