Optical isolators provide protection of expensive/complex lasers systems from damage due to back reflections into the laser. As lasers of ever higher powers are being deployed in applications such as laser processing, there is a need to scale the power handling of optical isolators as well. The standard geometry that is used for optical isolators consists of rods that are cooled at their cylindrical surfaces. This leads to the formation of a thermal lens and stress-induced birefringence in the media that limits the power handling of the isolator. We will use a different geometry with aggressive cooling to mitigate thermal effects. In this SBIR program, a kW-level optical isolator will be designed a prototyped suitable for an ultrafast laser system. We will also provide a path to a 100-kW optical isolator. The optical isolator that we will develop will enable higher performance in the laser processing field. Our optical isolator will provide protection again laser instabilities yielding poor machining results and laser damage eliminating the cost of replacing the laser and down time on the manufacturing floor.
