The basic optical receiver consists of a photodetector to convert the optical signal into a current, a low-noise preamplifier to convert and amplify the current into a voltage, an optional low pass filter to shape the received pulse or limit the bandwidth and a high-gain. The basic optical receiver consists of a photodetector to convert the optical signal into a current, a low-noise preamplifier to convert and amplify the current into a voltage, an optional low pass filter to shape the received pulse or limit the bandwidth and a high-gain. Optical audio, also known as TOSLINK or S/PDIF (Sony/Philips Digital Interface), is a digital audio connection that utilizes fiber optic cables to transmit audio signals between devices. Unlike traditional analog connections, optical audio ensures a pure and unadulterated transfer of sound, free. The optical audio port, also known as TOSLINK, can be useful for connecting older sound systems or linking devices like soundbars to TVs. TOSLINK cables use fiber optic technology to transmit digital audio signals, which makes them distinct from other types of audio cables that use electrical. I have two older receivers with Optical out, Denon 3808CI and Anthem MRX-710 but I don't think either will output from HDMI sources thru optical out, just optical inputs. So this may not work for you anyways. Every cable, from the wire between your receiver and speakers to the HDMI cable on your smart TV, contains copper wires inside. The one exception in home audio/video is the optical audio cable.