Physical reasons for optical interconnection

There are many physical reasons for using optics for interconnection within otherwise electronic information processing machines. These reasons are summarized and categorized based on the fundamental physical differences of the higher frequency, shorter wavelength, and larger photon energy of optics compared with electrical interconnections. Optics arguably solves or mitigates most of the physical problems that limit electrical interconnections, such as signal and clock distortion, skew and attenuation, impedance matching, cross-talk, power dissipation, wave reflection phenomena, interconnect density limitations, and voltage isolation. Optics also creates radical opportunities that have no analogue in existing electrical interconnections, such as free-space parallel interconnections, wavelength-division multiplexing, and the use of short optical pulses for timing and improved interconnect performance.