Monolithic multi-wavelength optical devices

A multi-wavelength photodetector structure comprising:

• a substrate;
• and
• a vertical structure over the substrate and extending away from the substrate along an axis, the vertical structure comprising:
• a first active region including one or more cascade stages of superlattices for light detection at a first wavelength;
• a second active region including one or more cascade stages of superlattices for light detection at a second wavelength different from the first wavelength, wherein the second active region is closer to the substrate than the first active region and spaced apart from the first active region;
• and
• an electrically conductive material along sidewalls of at least one of the first active region or the second active region.

An integrated circuit (IC) device for medium wavelength infrared (MWIR) or long wavelength infrared (LWIR), the device comprising:

• a substrate;
• and
• an epitaxial structure over the substrate and extending away from the substrate, the epitaxial structure comprising:
• a first active region including one or more cascade stages of superlattices for light emission at a first center wavelength;
• a second active region including one or more cascade stages of superlattices for light emission at a second center wavelength different from the first center wavelength, wherein a distance from the second active region to the substrate is shorter than a distance from the first active region to the substrate;
• and
• a middle region between the first active region and the second active region, the middle region including an absorbing material to absorb at least a portion of a shorter wavelength light emission of the first active region or the second active region.