I don't doubt there might be undisclosed info about UFOs, including maybe the Roswell incident, but pursuing the idea we got technology from UFOs doesn't seem very clever to me, it isn't likely to persuade anyone who has in depth technical education, which includes the history of development of various things including semiconductors and optic fibres. German scientists were working with semiconductor type devices around the time of Nikola Tesla and Marconi, even sharing the Nobel prize with Marconi for their work on semiconducting materials.
Optic fibres go even further back to roman times when glass was first stretched to fibres and the light conduction properties of those first started to be remarked on.
We would need to be uneducated in the history of technology to believe we didn't actually do all the work of developing those things you mentioned.