The best replacement for optical is laser mouse.

The best alternatives to optical are rated as following:
★★★★★  laser mouse
★★★★  digital zoom
★★★★  coaxial
★★★★  hdmi
★★  laser
★  digital image stabilization
★  coax
★  rca
★  coaxial audio
★  electronic viewfinder
★  laser mice
★  hdmi audio
★  digital audio
  digital coax
  metric kerning
  usb dac
  laser gaming
  hdmi for audio
  analog audio
  metrics
  aux
  coaxial cable
  spdif
  laser sensor
  digital coaxial
  toslink
  randolph engineering
  hdmi for sound quality
  laser wireless mouse
  component
  hdmi for sound
  hdmi cable
  rca audio
  coaxial digital
  radio telescopes
  3.5mm
  s-video
  electronic image stabilization
  geometric isomers

Your alternative for optical is not listed? Suggest!
Speaking about optical, one probably shouldn't forget about hdmi.

Other search terms related to optical and their ratings are:
★★★★★ hdmi
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Google Trends

Scale is based on the average worldwide traffic of optical in all years. Click on graph for more.
optical
laser mouse
digital zoom