A number of fluidic-photonic devices for allowing optical detection, systems employing such devices, and related methods of operation and fabrication of such devices are disclosed herein. In at least some embodiments, the devices can serve as flow cytometry devices and/or employ microfluidic channels. Also, in at least some embodiments, the devices are fluidic-photonic integrated circuit (FPIC) devices that employ both fluidic channels and one or more waveguides capable of receiving and/or delivering light, and that can be fabricated using polymeric materials. The fluidic-photonic devices in at least some embodiments are capable of functionality such as on-chip excitation, time-of-flight measurement, and can experience enhanced fluorescence detection sensitivity. In at least some embodiments, the devices employ detection waveguides that are joined by way of a waveguide demultiplexer. In additional embodiments, a variety of techniques can be used to process information received via the waveguides, including an iterative cross-correlation process.