The present disclosure relates to a sensor having a set of photodetectors that are arranged at various locations to enable the measurement of blood glucose. The photodetectors are arranged across multiple locations. For example, the detector may comprise multiple photodetector arrays that are arranged to have a sufficient difference in mean path length to allow for noise cancellation and noise reduction. Walls may be used in the detector to separate individual photodetectors and prevent mixing of detected optical radiation between the different locations on the measurement site. A window may also be employed to facilitate the passing of optical radiation at various wavelengths for measuring glucose in the tissue.