Dispersive type optical filter utilizing light-transmitting fiber elements

Claim 1

A CUT-OFF FILTER COMPRISING A LIGHT-CONDUCTING FIBER EMBODYING A LIGHT-TRANSMITTING CORE AND A LIGHT-TRANSMITTING MATERIAL SURROUNDING SAID CORE, SAID CORE AND SURROUNDING MATERIAL FORMING A LIGHT-REFLECTING INTERFACE THEREBETWEEN, SAID CORE AND SURROUNDING MATERIAL BEING FORMED OF MATERIALS HAVING A COMMON INDEX OF REFRACTION FOR LIGHT OF A SELECTED WAVELENGTH AND HAVING SUBSTANTIAL, DIFFERENT, DISPERSIVE POWERS SUCH THAT LIGHT CAN BE DIRECTED INTO THE FIBER CORE FROM ONE END THEREOF TO BE OBLIQUELY INTERCEPTED BY SAID INTERFACE AT SELECTED ANGLES TO THAT LIGHT OF AT LEAST SAID SELECTED WAVELENGTH CAN BE TRANSMITTED THROUGH SAID INTERFACE EXTERIORLY OF THE CORE AND LIGHT OF OTHER SELECTED WAVELENGTHS CAN BE TOTALLY REFLECTED A MULTIPLICITY OF TIMES FROM SAID INTERFACE TO BE CONDUCTED THROUGH THE CORE AND PROJECTED FROM THE OPPOSITE END THEREOF, SAID FIBER BEING ELONGATED AND BEING CURVED LONGITUDINALLY IN THE DIRECTION OF ITS LENGTH AND HAVING ITS ENDS ORIENTED RELATIVE TO SAID SURROUNDING MATERIAL AND TO EACH OTHER FOR RECEIVING LIGHT PROJECTED ALONG A PREDETERMINED LIGHT PATH AT SAID ONE END AND FOR PROJECTING LIGHT CONDUCTED THROUGH SAID FIBER FROM SAID OPPOSITE FIBER END OUT OF SAID LIGHT PATH.