- optical bistable device
- optical bleaching
- optical bleaching agent
- optical bleaching agent; fluorescent whitening agent
- optical branch
- optical breakdown
- optical brightness
- optical buffer
- optical burst
- optical burst switching，OBS
- optical cable
- optical camera
- optical camouflage
- optical cavity
- optical celestial navigation
- optical cement
- optical center
- optical ceramics
- optical chaos
- optical characteristics measurement
- optical character reader
- optical character reader, OCR
- optical character reader,OCR
- optical character recognition
- optical Chinese character recognition