The present work deals with the development and testing of optical components for application-specific lab-on-microchips (ALMs). These include, on one hand, monolithically integrated planar waveguides with a liquid core, and on the other hand, structured thin-film detectors made of amorphous silicon, which are hybrid bonded to the microfluidic system. The sensory innovations include a vertically polymer-insulated pin diode with a detection distance of 150 µm and a liquid waveguide to inject excitation light orthogonally to the detection direction of the sensor element into the analysis capillary. In application, an increase in the light share of pH-sensitive anthracene derivatives based on fluorescence was observed, reaching a limit of approximately ~5.25 fmol. Additionally, the detection of a specific ruthenium(II)-based sensor molecule for metal ions of lead, mercury, and copper was successfully studied at a measurement volume of 1.2 nl over a concentration range of three orders of magnitude, up to a substance amount of ~66 nM.