Avshae, any chance we will see fiber-optic circuit boards in the future?
Currently network information typically travels over a medium such as copper or fiber, (or electromagnetic waves in the air, which is a different story), until it reaches a network node such as a switch or end-point, such as your modem at home. There it is converted into digital electrical signals for processing, which is done on a system which resides on a circuit board. From there it might be reconverted and retransmitted over fiber/copper/wireless.
So, you are asking, will it be possible to skip the conversion to electrical and do the entire processing optically. Well there are definitely people working on it, but it'll take years of research before computation in optics will be able to do what transistor-based processors are able to do today. MEMS (Microelectromechanical systems) might be the key. MEMS researchers try to do stuff like fabricate miniaturized motorized directional mirrors on a silicon die, to do computation in optics. Fascinating stuff for your PhD research.