optical device vs device

optical device and device both are nouns.

Word	Noun	Adjective	Verb	Adverb
optical device	Yes	No	No	No
device	Yes	No	No	No

As nouns, device is a hypernym of optical device; that is, device is a word with a broader meaning than optical device:

optical device (noun)	device (noun)
a device for producing or controlling light	any clever maneuver
	an instrumentality invented for a particular purpose
	an emblematic design (especially in heraldry)
	any ornamental pattern or design (as in embroidery)
	something in an artistic work designed to achieve a particular effect