Measuring Small-Beam MFD: Overcoming the Challenges

By Derrick Peterman, Ophir Photonics

Accurate beam size measurements for beam sizes under 10 μm are critical for many applications such as fiber optic coupling efficiency, defect scanning, optical design, and optical fabrication process control. The challenges for such a measurement include the use of focal plane arrays that are too large to reasonably profile without magnification, the high mechanical precision of the beam profiling apparatus, and the beams’ high divergences and rapid expansion. Reliable profiles for such small beams, however, can be obtained using near-field or far-field profiling techniques. This article presents and in-depth discussion of each technique, diagrams for their systems' set-up, and the benefits for using each one. Download the full article for more information.