fiber-optic transmission system vs fibre-optic transmission system

fiber-optic transmission system and fibre-optic transmission system both are nouns.

Word	Noun	Adjective	Verb	Adverb
fiber-optic transmission system	Yes	No	No	No
fibre-optic transmission system	Yes	No	No	No

As nouns, fiber-optic transmission system and fibre-optic transmission system are synonyms defined as:

fiber-optic transmission system and fibre-optic transmission system: a communication system using fiber optic cables

Other synonyms of fiber-optic transmission system include FOTS.

fiber-optic transmission system (noun)	fibre-optic transmission system (noun)
a communication system using fiber optic cables	a communication system using fiber optic cables