We report on 1N branching devices for fiber-optic networks. A novel Y-pattern mask for loss reduction in branching waveguide has been investigated based on simulation. 18 branching waveguides fabricated by ion-exchange proved that the scattering loss at the branching region made with novel Y-pattern is reduced considerably. Pigtailing technique has been developed using glass fiber arrays (FAs). The fibers in FA are aligned precisely, so that all fibers can be easily and precisely put into alignment with the output ports in a branching waveguide chip at the same time. A glass plate is used for reinforcement which improves mechanical and thermal stability of the device. Reliability of packaged devices is being strongly demanded. Various reliability tests have been performed with packaged 18 branching devices and those results are presented.

The authors found that the coloration in appearance as a noticeable defect of super twisted nematic LCD (STN-LCD) can be cancelled out and monochromatic display can be realized by adding an optical compensator to the STN-LCD. This NTN mode display shows the steepness of threshold characteristic and the response times equivalent to those in STN, but its contrast ratio, viewing angle, and multiplex driving capability are far better than those in STN. A liquid crystal cell is used as a compensator. Monochromatic display can be done when both display cell and compensator cell satisfy the following three conditions. (1) Product values nd of display cell and compensator cell coincide with each other. (2) The twist angles of liquid crystal layers are opposite to each other in their helix, but equal to each other in their absolute values. (3) The liquid crystal molecular directors adjacent to the opponent substrates of two cells are perpendicular to each other. In order to satisfy condition (1), the NTN cell gap must be controlled severer than the STN cell gap. The authors fabricated a prototype full-color NTN-LCD, and obtained an excellent contrast ratio of 10:1 to 17:1 by driving it at 1/240 duty ratio.