5 ms·
I seem to recall information travels slower in fiber (optical) vs wires (electric), resp. ~2c/3 vs ~c, or am I remembering it wrong? Or is it a significantly di
by lloeki 2y ago
I seem to recall information travels slower in fiber (optical) vs wires (electric), resp. ~2c/3 vs ~c, or am I remembering it wrong? Or is it a significantly different optical medium?
If so, does that matter at all here? Dunno if that holds up for such kind of devices and/or at these scales (much shorter distance, but also much higher speed).
- Terr_ 2y agoIIRC the lower speed in fiber-optic cables has to do with the the refractive index of the glass, and maybe some bouncing introduced by curvature. I'm not sure what kind of refractive indices are possible in much smaller photonic circuits, particularly if it's not practical to develop and run everything in a permanent vacuum.
- deleted 2y ago[deleted]
- cycomanic 2y agoIn general that's correct, however it's not quite as simple. For latency you need to consider group velocity (not phase velocity), which depends on the waveguide and frequency of the EM wave. I'm actually not quite sure what it is for electric waves, but for most photonic structures it's very similar to the phase velocity. The phase velocity is about c/1.5 for silica, but more like c/3.5-c/2 for most materials used in photonic integration. I'm not an expert on integrated electronic circuits, but I guess the difference could matter depending on application.
- hughesjj 2y agoI'm thankful you posted this and adjacent chain of responses and I enjoyed learning what you shared =) Viva la HN