An optical glucose sensor may include an optical fiber and a glucose-permeable membrane having a hollow interior and being coupled to the optical fiber's distal end. The membrane's hollow interior provides a compartment to house a competitive glucose binding affinity assay. The assay may include a glucose analog that may be labeled with a dye, and a glucose receptor that may be labeled with a fluorophore. The optical fiber may include a compound parabolic concentrator tip, and the compartment may additionally house a reflector disposed so as to face the optical fiber's tip. A fluorophore-labeled assay may be interrogated by an optical interrogating system including a light source and a filter substrate having one or more coatings to effect, e.g., an excitation filter and/or an emission filter. The interrogating system may be manufactured as a stacked planar integrated optical system and diced into smaller units.
