In this paper, a novel coupler-type wavelength demultiplexer composed of the K+-ion diffused waveguides, which has an adjustment function for optimizing the diffusion depth, is proposed to achieve reliably the high extinction ratio. The optimization in the diffusion depth is made by repeating the K+-ion diffusion and extinction-ratio measurement alternatively, and the high extinction ratios more than 20 dB are measured reliably at both operation wavelengths of 0.6328 and 0.83 µm. Experimental results on the polarization dependence in the extinction-ratio adjustment are also reported.

A new many-valued JK type flip-flop is proposed. Many-valued sequential machines are designed by different types of many-valued flip-flops to compare their costs.

A method is proposed to design synchronous mod N counters (logical type) by using many-valued JK flip-flops. Then costs of the counters are derived.

A method is presented to synthesize many-valued majority elements which can correct errors and simultaneously realize logic functions.

A schematic method of determining the functional form of a given three-valued majority function from its weights and thresholds is presented.