Silicon photonics has emerged as one of those areas of such far-reaching potential that its challenges and benefits tend to be clouded in generalities. Light as the main medium does indeed promise to alter fields including biological and chemical sensing, navigation, radio frequency sensing, communications, but for our purposes here, the potential within large-scale computing is of greater interest...We shouldn't be holding our breath for photonic devices to make it to market and hit large systems within the next year or even for the next few years, says David Calhoun, a PhD fellow who focuses on the integration of photonic devices with larger systems at Columbia University's Lightwave Research Laboratory.
https://www.nextplatform.com/2016/01/21/light-at-the-end-of-the-silicon-photonics-tunnel/