The first two posts linked below mention the use of a 6 meter fiber optical cable between Curiosity's ChemCam's receiver telescope on top of a tower and the spectrometer used to analyze the collected light tucked away in the belly of Curiosity.
Presumably Perseverance's upgraded SuperCam is similar in this regard.
Are these the first, and the only use of fiber optic cables beyond cis-lunar space, or is it more widespread?
- How cold do Curiosity's & Perseverance's appendages get at night with all those sensitive cameras and lasers?
- this answer to Has ChemCam been used to characterize the martian atmosphere?
Fiber in space:
- Could multimode (polymer) optical fiber Gigabit Ethernet be a better choice than WiFi inside future satellites?
- Is there a space-certification procedure used by commercial spacecraft manufactures for electronic components?
- Has Made in Space any track record growing specialty crystals in microgravity before? ("Industrial Crystal Facility" to fly this year)
- How well would optical fiber work on the Moon or Mars?
- Use or tests of multimode optical fiber for cubesat battery charging or datalink while in storage, or waiting to launch?