Abstract: A quantum cryptographic key distribution (QKD) endpoint (405) includes a QKD receiver and a feedback system (1600). The QKD receiver receives symbols transmitted over a QKD path. The feedback system (1600) controls a length of the QKD path based on the received symbols.

Abstract: A quantum cryptography system [100] may include a transmitter [110] configured to generate entangled first and second photons, modulate and detect the first photon, and transmit detection information and the second photon. The system [100] may also include a receiver [160] configured to modulate the second photon. The receiver [160] may also be configured to detect the second photon based on the detection information.

Abstract: An optical fiber can be coupled to a semiconductor light source or detector using molded lens elements. The apparatus is easy to assemble, it is inexpensive, and it achieves true hermetic sealing of the semiconductor for a good reliability.

Abstract: The mosaic image screen of a shadow mask color tube has a plurality of sets of elemental screen areas, each of which areas includes a phosphor for emitting light of one of three primary colors and a filter which is transmissive of that color but otherwise is essentially a visible light attenuator. The color filter for the first set is formed by applying a thin film of a metallic resinate of a particular color onto the faceplate, directing a laser beam to the elemental screen areas for the other two primary colors to liquify the film and to withdraw the liquefied film from these areas, and heating the entire film to raise the energy threshold at which liquefaction occurs. Second and third metallic resinate films of the other two colors are similarly processed, and then all three films are heated to volatilize their respective organic material to form the color filters.