| 摘要 |
PROBLEM TO BE SOLVED: To provide a practical waveguide circuit which includes a lot of intersections and has a low loss. SOLUTION: The width of the core of the waveguide is w<SB>1</SB>at input/output terminal parts 22 and 26, w<SB>2</SB>at the intersection portion 24, and w<SB>2</SB>>w<SB>1</SB>. The intersection pitch of waveguides 27 at the intersection portion 24 has a constant value d and the intersection angle isθ. The optical wavegiude circuit is so set that the width of the core at the intersection portion 24 is different from the width of the core at the input/output parts 22 and 26, or the height of the core at the intersection portion is different from the height of the core at the input/output terminal parts 22 and 26, the width of the core is smoothly varied with a taper portion 23 between the input/output terminal parts 22 and 26 and the intersection portions 24. In a case where the number of the waveguides 27 intersecting the intersection portion 24 is 100, the intersection loss is 5.8 dB for a conventional case where w<SB>2</SB>=w<SB>1</SB>=5μm, the intersection loss of the present waveguide circuit where w<SB>2</SB>=12μm is 1.8 dB, resulting in a remarkable decrease in the intersection loss. COPYRIGHT: (C)2003,JPO |
