This disclosure is generally concerned with optical systems that employ guided-mode grating resonant reflector filters (“GMGRF”) to facilitate wavelength and/or polarization selectivity in the optical system. In one example, an optical system is provided that includes first and second tunable detectors. Each of the tunable detectors includes a GMGRF that is tuned to select a corresponding optical wavelength and/or polarization of an optical data channel, such that the optical wavelength and/or polarization associated with the first tunable detector is different from the optical wavelength and/or polarization associated with the second tunable detector. In this way, an array of tunable detectors can be employed to select some or all of the wavelengths and/or polarizations of an optical data signal having a plurality of data channels.