TOSLink splitters work fine in reverse but you can only have one of the two sources on at a time. If they’re both on, neither works.
Is optical out the same as audio out?
Though they are both commonly used in speakers and transmit audio, the ways they work are entirely different. This difference comes down, in part, to their connectivity: optical is digital and aux is analogue.
Does Nintendo switch have optical out?
I was pretty bummed to find out there is no Optical Audio on the Switch, let alone some way to hooking up a headset to the Switch while docked.