Patent ID: 9690044
Date: 2017-06-27
CPC Classifications: G02B

Claim:
1. A waveguide mode converter, wherein the waveguide mode converter is a rib-type waveguide placed in a connection section of a rib-type waveguide and a channel-type waveguide and includes a tapered section, and wherein a first core layer, of the rib-type waveguide, comprises a first portion and a rib projecting above the first portion, the tapered section extends on both sides of the rib positioned between the first core layer and the channel-type waveguide, and a width of the tapered section changes in a direction which is parallel to a waveguide direction; a height of the tapered section which is substantially equal to a height of the first portion of the first core layer, wherein a width change of the tapered section is denoted as Ts, a width of the first core layer, including the tapered section, in a direction parallel to the waveguide direction is denoted as Wr, a width of a second core layer, of the channel-type waveguide, is denoted as Ww, a length of the tapered section is denoted as Lt, and a value of (Wr−Ww)/Lt is denoted as Ts, the value of Ts indicating that the width change of the tapered section is smaller than 0.01.