Automatic Power Control

This kit is designed for fixed wavelength lasers. The value of the wavelength is an input parameter for the control software and must be entered manually. The computer controlled closed loop attenuator sets and maintains the power by positioning the ½ wave-plate based on a feedback signal from a photo detector which can exhibit a strong dependence on wavelength.

Schematic of the CCVA-L-KT kit.

Attenuate Light by a Factor of 1000

Depending on the choice of components the attenuator is suitable for laser wavelengths ranging from 400 nm to 1100 nm, and average powers from 1nW up to 20 Watts (500 Watts/cm2 damage threshold). This device is capable of attenuating light by a factor of 1000 while still maintaining an error of less than 10%. The algorithm used to control power operates in a closed loop with PID (proportional, integral, derivative) feedback, compensating for slow changes in output power within the bandwidth of the device greater than 500 ms.

Reference Software

The software included with this product is for reference only. It has been tested in the experimental setup described in our Computer Controlled Variable Attenuator for Lasers application note. The software will need to be customized by the user for additional experimental requirements. At the present time, Newport provides limited support for this software and any concern should be discussed with Newport before purchasing the product.


Applications for this variable attenuator kit include:

Please see our Computer Controlled Variable Attenuator for Lasers application note for more information.