Apparatus for transmitting light through Cassegrain optics

An active optical system comprising:

• a light source;
• a centrally apertured primary mirror where the aperture is small compared to the overall size of the primary mirror;
• a secondary mirror placed with respect to said primary mirror so it can receive light from the aperture and reflect it onto the primary mirror;
• a fiber optic bundle placed with respect to said light source and said primary mirror such that the angle of incidence to receive light from the source and transmit it through the aperture and exit as annularly shaped beam toward the secondary mirror is less than the critical angle of total reflection for the given materials used between the source and the fiber optic bundle;
• and
• means for directing the light so that the angle of incidence on the fiber optic bundle is other than zero degrees for plane waves and so that the non zero angle for converging light refers to the incident angle of the ray traveling along the axis of symmetry of the converging light.