Abstract: A method of manufacturing a semiconductor device for forming with high accuracy a marker used for separating a semiconductor device 10, wherein a plurality of semiconductor devices 10 are fabricated in a semiconductor substrate 16 are separated, and wherein etched grooves 31 are formed outside the semiconductor regions in the semiconductor substrate 16.

Abstract: There is provided an optical wave-length filter which is constituted by a wave-guide route formed on a surface of a substrate; a front stage polarizer disposed in the wave-guide route for transmitting as an input light either TM mode light or TE mode light; a plurality of mode-converters disposed in the wave-guide route for mode converting one TM/TE-mode light transmitted from the front stage polarizer having a conversion wave length corresponding to an output light of the optical wave-length filter into the other TE/TM-mode light; and a rear stage polarizer disposed in the wave-guide route for transmitting as the output light of the optical wave-length filter the other TE/TM-mode light; the mode-converters being constituted by a finger-type electrode for control and a finger-type electrode for earthing interdigitally coupled for each other and disposed along the wave-guide route.