SUMMARY
Fiber Optic Delay Lines (ODL) consist of an input and output fiber collimator to project the light into free space and collect it again into a fiber. The distance the light travels in free space is precisely controlled, either by controlling the separation between the input and output optics, or by reflecting the light off a movable reflector. In either case, by varying the distance the light travels, one can control the delay time through the device.
