Much has been said about optical communications. Ultra wide bandwidth, almost loss free communication over large distances. Much better tha copper wires. Typically we talk about transmission by fibre, the light is guide from source to destination just like a railway line. We can insert optical switches, multiplexors, just like in the copper world. With WDM multiple colours can be used in the same fibre to increase capacity. We can use multi-orthoganal modulation to in effect achieve parallel transmission of data.
If we take away the fibre the same can be done in free air (a reflector mirror on the ceiling would be an enhancement). An Ethernet type enviroment can be created allowing CMSA/CD between multiple peers. A token ring priority type environment could also be envisaged, here we have multiple tokens floating in the air (al la WDM). A device gets a free token and broadcasts on it, due to the WDM effect dozens of tokens could be in the air at the same time. By using optical filters on the receivers we can restrict the communication to between specific devices if we require.
Now lets go further an miniturise everything to chip or multi chip level. We cover a chip with a fibre like coat/layer that achieves internal reflection between different areas of a chip or even other chips. Faster tha copper, much less loss than copper, less heat....
By doped grading and etching of the optical surface the we can direct/control the light between different areas/chips. For example using multiple frequencies we could achieve parallel memory access between a CPU and optical memory ( For example the data via a WDM approach and addressing via orthoganal modulation)!
Want a high speed connection between two chips, then etch the coat to make a psuedo waveguide between the two areas(care with possible evanesence mode propagation). I.C technology we could make embedded optical switches to direct or On/Off flows. I envisage something like an optical amplifier, shine a specific light frequency on it and the characteristics change.
Of cause we are dependent on there being an extremely small (transistor size) light source/receiver/modulator
Diagram of optical scheme required here
Now that is one way of doing it, direct excitation of LED dots + a modulations, differently doped dots for different frequencies. We can use led groups to get both amplitude a phase modulation. Now what about the reverse, in-direct excitation, we flood the optical layer with with a broad band of radiation that provides energy for band jumping like in a laser but controlled by an electrical or capacitive change to vary the band gap properties.