Fiber optic collimators are disclosed for use in 
fiber optic rotary joints (20) providing for improvement in 
insertion loss performance. One embodiment of the 
fiber optic 
collimator has a gradient-index rod lens (61) possessing a 
pitch of less than one-quarter. Improvement in 
insertion loss arises due to the increase in the effective 
focal length of the lens as the 
pitch is reduced, allowing the 
collimator to achieve a longer working distance. The increase in the effective 
focal length is accompanied by an increase in the back 
focal length of the lens, compared to the zero back focal length of the more typical quarter-
pitch gradient-index rod lens. The increased back focal length can be filled by a cylindrical glass spacer (64), to which an 
optical fiber (68) is attached, resulting in a 
collimator with very similar form factor to the usual quarter-pitch gradient-index rod lens collimator. The increased back focal length can also be filled by a form of right-angle 
prism (71), to which an 
optical fiber is attached such that the 
fiber is oriented at 90 degrees to the 
optical axis of the lens useful for applications of pancake-style 
hybrid slip rings wherein the desired direction of fiber ingress to the rotary joint is perpendicular to the rotation axis of the rotary joint.