An electronic circuit device, including a combined optical transmission and cooling fluid conduit network. The network includes at least one cooling conduit having an optical transmission medium. The network is configured to convey a cooling fluid via the at least one cooling conduit and to convey an electromagnetic signal via the optical transmission medium. The network is in thermal communication with a first set of one or more components of the electronic circuit device and in signal communication with a second set of one or more components of the electronic circuit device. The first set and second set of components are at least partly overlapping. A method for conveying optical signal in such an electronic circuit device is also provided.