Optical isolator integrated with optical devices

A method, comprising:

• forming a first waveguide having a first length extending along a first direction, a first width extending along a second direction that is orthogonal to the first direction, and a first height extending along a third direction that is orthogonal to the first and second directions;
• forming a second waveguide aligned with the first waveguide along the first direction, the second waveguide having a second length extending along the first direction, a second width extending along the second direction, and a second height extending along the third direction, the second length of the second waveguide entirely overlapping the first length of the first waveguide along the second direction;
• and
• forming an optical isolator between the first waveguide and the second waveguide, the optical isolator having a third length extending along the first direction, a third width extending along the second direction, and a third height extending along the third direction, the third height being greater than at least one of the first height or the second height, the optical isolator being formed of a material that is different from a material of the first waveguide or a material of the second waveguide.

A multiplexing device, comprising:

• a first waveguide having a first length extending along a first direction, a first width extending along a second direction that is orthogonal to the first direction, and a first height extending along a third direction that is orthogonal to the first and second directions;
• a second waveguide aligned with the first waveguide along the first direction, the second waveguide having a second length extending along the first direction, a second width extending along the second direction, and a second height extending along the third direction, the second length of the second waveguide being greater than the first length of the first waveguide;
• and
• an optical isolator being partially positioned between the first waveguide and the second waveguide, the optical isolator having a third length extending along the first direction, a third width extending along the second direction, and a third height extending along the third direction, the third height being greater than at least one of the first height or the second height, the optical isolator being formed of a material that is different from a material of the first waveguide or a material of the second waveguide.