"optical" - key terms from Wikipedia

asahi optical
high definition optical disc
nintendo optical disc
nonlinear optical
optical
optical activity
optical amplifier
optical axis
optical camouflage
optical carrier
optical cavity
optical character recognition
optical coherence tomography
optical communication
optical communications
optical density
optical disc
optical drive
optical drives
optical effects
optical fiber
optical frequency
optical heterodyne detection
optical illusion
optical illusions
optical media
optical mice
optical microscope
optical microscopy
optical modules
optical mouse
optical network
optical phase conjugation
optical phenomena
optical phenomenon
optical power
optical printer
optical quality
optical seti
optical sight
optical signal
optical sound
optical storage
optical system
optical systems
optical telescopes
optical tracker
optical zoom
passive optical network
synchronous optical networking