Integrated photonic transceiver

A method of forming a wavelength-division multiplexed (WDM) transceiver, the method comprising:

• providing a substrate with a first z-height measured in a z-direction at a first portion of the substrate and a second z-height measured in the z-direction at a second portion of the substrate that is different than the first portion;
• providing a first insulator layer over the first portion of the substrate;
• providing a second insulator layer over the second portion of the substrate;
• providing a first waveguide over the first insulator layer, the first waveguide having a first thickness measured in the z-direction at a first portion of the first waveguide and a second thickness measured in the z-direction at a second portion of the first waveguide, wherein the second thickness is greater than the first thickness;
• and
• providing a second waveguide over the second insulator layer, wherein the second waveguide is coupled with a portion of the first waveguide, wherein the first waveguide includes silicon, and the second waveguide includes silicon and nitrogen.

A wavelength-division multiplexing (WDM) transceiver, comprising:

• a substrate with a first z-height measured in a z-direction at a first portion of the substrate and a second z-height measured in the z-direction at a second portion of the substrate that is different than the first portion;
• a first insulator layer over the first portion of the substrate;
• a second insulator layer over the second portion of the substrate;
• a first waveguide over the first insulator layer, wherein a portion of the first waveguide tapers in a direction perpendicular to the z-direction;
• and
• a second waveguide over the second insulator layer, wherein the second waveguide is coupled with a portion of the first waveguide, the first waveguide includes silicon, the second waveguide includes silicon and nitrogen, and the second waveguide does not taper in the direction perpendicular to the z-direction.