Cylindrical rod lenses are highly polished small diameter rods made of optically transparent homogeneous materials. A carefully controlled manufacturing process produces rods (or fibers) with precise diameters and unsurpassed surface quality.
When illuminated sideways, these rods (or fibers) act as cylindrical lenses whose numerical aperture is proportional to their refractive index. The rods are cut to desired length and can be ground on top and/or bottom relative to the direction of the optical axis in order to facilitate packaging and orient AR coating. The round cross-section of these lenses results in a large field of view and a simple and cost-effective alignment where most of the positioning errors result in simple focusing errors.
These lenses can be used either as fast-axis collimators for single laser diodes or for building cylindrical lens arrays for laser diode bars.
In order to accommodate a small emitter pitch, the edge of the lens may be ground to a desired width.