| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical band-pass filter which has superior rectangularity and a periodic transmission spectrum whose repetition period is controlled with high precision. SOLUTION: The optical band-pass filter which selectively transmit only light signals within a specified light frequency range among inputted light signals has on a plane substrate a couple of array waveguide diffraction gratings each having an input (output) waveguide, an array waveguide which is configured to increase in waveguide length by a specified waveguide length difference in order, a 1st slab waveguide which connects the input (output) waveguide and array waveguide, and a 2nd slab waveguide connected to the other end of the array waveguide; and a couple of 2nd slab waveguides are so arranged that the center line of the couple of slab waveguides is shared and the focus position on the center line is coincident, and a spatial filter provided partially with an opening part is arranged on the connection surface of the couple of 2nd slab waveguides as a plane which is perpendicular to the center line and passes the focus position. COPYRIGHT: (C)2004,JPO |
