I worked closely with some of these devices at a previous employer. Might've even fried one at some point. I'm pretty excited about what other things they can be used for!
Nice to see some more posts about light communications on HN. I have had the pleasure talking with people who developed this tech & see it in action.
Apparently, it is a big step towards purely optical network switching.
Once optical comb sources become economically available off the shelf, they should be game-changers in several fields from spectroscopy to time/frequency work. Right now everything you can buy is still around 6 figures AFAIK.
> seamlessly connected to optical waves that oscillate at 10,000 times higher frequencies
Somehow four orders of magnitude sound too less for the transition from radio to light, but it makes sense. A i9 processor works at ~6 GHz, and light is at the THz range
Microwave communication goes comfortably into the tens of gigahertz range, and visible light is in the hundreds of terahertz. So it is about a factor of 10,000.
And in between you have the terahertz gap, where we have no effective technology to emit or receive these frequencies.
But one giga to one tera is just 1000.
From 50 GHz to 500 THz we have 10,000.
Perhaps I'm being pedantic, but in the video, when they show multi-spectral light coming in from the left, they show low-frequency light moving faster than high-frequency light. ("Survey says: EEEEEHHHHHNNNNNNK!")
I was also hopeful the video would have actual info on how they work, but no such luck. Just a lot of "Are they cool, or what?".
Don't be too hard on the video or article. I just went through the Frequency_comb Wikipedia article and I'm still none the wiser.
Well, I did get an idea about what the thing actually is: basically a signal consisting of a mixture of frequencies, precisely spaced. Techniques to generate some of the bands include nonlinear mixing. Turns out, light can undergo distortion, so you can get intermodulation distortion to generate colors not present in the inputs.
The unclear part is the details of how the frequency comb is hooked together with the radio frequency domain in a feedback loop to control the comb. I.e. where in the RF domain we have the precise frequency reference we'd like to convey to the optical domain.
Red light does go through non-vacuum faster than blue light. They're equal in a vacuum.