OPTICAL ELEMENT, OPTICAL TRANSMITTER, OPTICAL RECEIVER, OPTICAL TRANSMITTER-RECEIVER, AND METHOD OF MANUFACTURING OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide an optical element having a low optical loss.SOLUTION: An optical element 10 includes: a first clad layer 12; a core layer 13 which is disposed on the first clad layer 12 and extends in a direction from a first end part 10g for light input/output to a second end part 10h while having a cross-sectional area increased from the first end part 10g; a slab layer 14 which is disposed on the first clad layer 12 and extends in the direction from the first end part 10g to the second end part 10h; a rib layer 15 which is disposed on the slab layer 14 and extends in the direction from the first end part 10g to the second end part 10h while having a cross-sectional area decreased up to the second end part 10h; and a second clad layer 16 disposed on the core layer 13 and the rib layer 15. The core layer 13, the slab layer 14, and the rib layer 15 are optically coupled by a part having a maximum cross-sectional area of the core layer 13 and a part having a maximum cross-sectional area of the rib layer.