Abstract: An apparatus, methods, and a system for a photonic biosensor are disclosed. The photonic biosensor includes a substrate having a sample addition zone in fluid communication with a wicking zone and a sample detection zone. The substrate also includes an optical input port configured to optically couple to a light source and an optical output port configured to optically couple to a light detector. The photonic biosensor also includes a photonic integrated circuit (“PIC”) connected to the substrate. The PIC includes a first grating coupler aligned with the optical input port, a second grating coupler aligned with the optical output port, at least one waveguide between the first grating coupler and the second grating coupler, and at least one detection element disposed within the at least one waveguide.