Optical waveguide, corresponding coupling arrangement and method

An optical coupling arrangement, comprising:

• first and second optical waveguides;
• and
• a third optical waveguide that provides an optical propagation path between said first and second optical waveguides, third optical waveguide including:
• first and second end sections for optical radiation to propagate in a longitudinal direction therebetween and an intermediate section extending between the first and second end sections, wherein:
• the intermediate section includes first and second portions superposed in a superposition direction transverse to the longitudinal direction,
• the first end section has a first height in said superposition direction corresponding to a sum of heights of the first and second portions of the intermediate section in said superposition direction, and
• the second end section has a second height in said superposition direction corresponding to the height of the first portion of the intermediate section.

A method of making an optical waveguide, comprising:

• forming first and second end sections for optical radiation to propagate in a longitudinal direction therebetween and forming an intermediate section extending between the first and second end sections, wherein:
• forming the intermediate section includes forming first and second portions superposed in a superposition direction transverse to the longitudinal direction,
• the first end section has a first height in said superposition direction corresponding to a sum of heights of the first and second portions of the intermediate section in said superposition direction, and
• the second end section has a second height in said superposition direction corresponding to the height of the first portion of the intermediate section.