We report for the first time a hybrid polymeric microfluidic device with optical detection for microfluidic droplet-based systems. The device consists of a fluidic part and an optical part. Microchannels were fabricated using CO2 laser. The microfluidic part consists of two microchannels for forming droplets of an aqueous liquid in an immiscible carrier liquid. The optical part consists of two optical fiber for light emission and light detection. Microdroplets are formed, when the aqueous liquid is injected into the carrier flow. The formed bubbles pass the optical detection and diffract some of the incoming light. The detected signal from the other optical fiber can be evaluated for droplet size, droplet shape, and droplet formation frequency.