Abstract: Flexible, low-cost, physically robust optical coupling patches for use in spectrophotometric patient monitoring, and methods of fabrication thereof, are described. The optical coupling patch comprises a flexible base layer having a skin-contacting surface and a first aperture formed therethrough that establishes an optical interface with a skin surface when the base layer is placed against the skin surface. The optical coupling patch further comprises an elastomeric waveguiding member laterally disposed on a surface of the base layer opposite the skin-contacting surface. The optical coupling patch guides optical radiation between a laterally propagating state at a first location laterally distal from the first aperture and a generally vertically propagating state at the first aperture.