Polarization beam splitter

A method comprising:

• in a first longitudinal segment of an apparatus that includes a first waveguide and a second waveguide including a first layer and a second layer, arranging the first layer so as to gradually approach the first waveguide in a first transverse direction;
• in the first longitudinal segment, offsetting the first layer from the first waveguide in the first transverse direction by a first gap and in a second transverse direction by a second gap;
• in a second longitudinal segment of the apparatus adjacent to the first longitudinal segment, longitudinally orienting the first and second waveguides;
• in the second longitudinal segment, offsetting the second layer from the first waveguide in the first transverse direction by a third gap and from the first layer in the second transverse direction by a fourth gap;
• in a third longitudinal segment of the apparatus adjacent to the second longitudinal segment, gradually decreasing a width in the first transverse direction of a length portion of the first layer along a first longitudinal direction;
• and
• in the third longitudinal segment, gradually increasing a width in the first transverse direction of a length portion of the second layer along the first longitudinal direction.

An apparatus comprising:

• a first waveguide configured to receive a transverse electric mode signal polarized in a first transverse direction and a transverse magnetic mode signal polarized in a second transverse direction and to output the transverse electric mode signal;
• a second waveguide including a first layer and a second layer configured to output the transverse magnetic mode signal;
• and
• a first longitudinal segment, a second longitudinal segment adjacent to the first longitudinal segment, and a third longitudinal segment adjacent to the second longitudinal segment, wherein:
• in the first longitudinal segment, the first layer gradually approaches the first waveguide in the first transverse direction, the first layer is offset from the first waveguide in the first transverse direction by a first gap and in the second transverse direction by a second gap, and the second layer is offset from the first waveguide in the first transverse direction by a third gap and is offset from the first layer in the second transverse direction by a fourth gap,
• in the second longitudinal segment, the first and second waveguides are longitudinally oriented, and wherein the second layer is offset from the first waveguide in the first transverse direction by the third gap and is offset from the first layer in the second transverse direction by the fourth gap, and
• in the third longitudinal segment, the first layer includes a length portion having a width in the first transverse direction that gradually decreases along a first longitudinal direction, and the second layer includes a length portion having a width in the first transverse direction that gradually increases along the first longitudinal direction.