I'm not sure Star Trek ever really defined what an "isolinear chip" was formally -- although there are numerous Star Trek Encyclopedias and similar that contain this jargon. And it's probably a good thing too, as isolinear has a real, technical meaning in mathematics, at a minimum:
iso+linear => on the same line
It sure sounds fancy though -- and makes for great technobabble. Likewise, Voyager used some sort of neural mumbo-jumbo completely unrelated to modern neural networks.
Optical data transmission has been a thing for a long time (late 50s?). Optical data processing is relatively new, but since at least 2005ish there's been significant research there. Good wikipedia rabbit holes can be found if you start here: https://en.wikipedia.org/wiki/Optical_computing