The plot below shows a measurement of thermal lensing in only 270 watts from a single mode fiber laser using the Haas Laser Technologies, Inc. M-squared measurement system based upon the use of dual BWA-CAM cameras. The measurement shows a thermal shift of about 1.5 mm within 30 seconds of operation.
A laser beam is directed into a polarization insensitive attenuator either as a collimated beam or an optical fiber collimator with a variety of fiber connection choices for a real plug and play operation. One BWA-CAM is set for the first Rayleigh range and the second BWA-CAM is set for greater than the third Rayleigh range. This combination provides the highest speed, real time M2 measurement on the market with no moving parts. This system easily measures thermal lensing and all ISO parameters in real time with frame rates exceeding 12 frames per second.
As the BWA-CAM is based upon the use of a pair of Fabry-Perot resonator optics and the spacing between the optics creates "time" slices of the beam, the entire beam waist is imaged on the camera sensor so that the full beam waist caustic can be visualized and measured without any moving parts. Further, the spacing of the Fabry-Perot is user adjustable to accommodate short or long Rayleigh lengths. This design provides a more consistent and stable measurement of a laser system's focusing characteristics.

Parameter Name	Parameter Value
Function	thermal
Sensor	CMOS
Interface	GigE