Focus Adjustable Fiber Collimators can adjust beam diameter at specified distance by screwing a ring, which drives a lens stuck to it and changes the distance between this lens and fiber at last. Naturally, devices for larger collimated beams need to be both longer and larger in diameter. FiberPorts can be used to provide a stable platform for coupling light into and out of FC/PC, FC/APC, or SMA terminated fiber with five or six directional adjustments. 1 This animation provides an introduction to the mechanism of the FiberPort and shows how the FiberPort can be used as a collimator. For more information, please see the Alignment Procedure tab. Thorlabs' compact, ultrastable FiberPort micropositioners provide an easy-to-use platform for. The adjustable focus fiber collimator provided by JCOPTIX consists of three parts: an external stainless steel housing, a compression spring, and a non spherical lens. The non spherical lens coated with anti reflective film is loaded on the spring, and the focus is adjusted by rotating the. Fiber-optic collimators are used to launch the light from an optical fiber into a free space collimated beam with specified beam diameter or spot size. There are lenses (often GRIN lenses) which can be attached to fiber endfaces for performing some optical function — typically, collimating the light coming from a fiber to a diameter which is substantially larger than the fiber mode (→ fiber collimators).