Headline seems misleading. They’re buildings detectors for someone, not ‘betting’ on it.
The word is mostly used for finance investment promotion. I'd guess that it's written to attract those bloggers/casters, and make money for somebody.
TSMC bets on unorthodox optical tech
61–70 of 110 posts
Re: TSMC bets on unorthodox optical tech
#62With this design, how do they route enough pins from the chip to the optical transceiver? Would it take chiplets to get enough lanes?
Re: TSMC bets on unorthodox optical tech
#63Earlier quoted context omitted.
I think this is intended for short distances (e.g. a few cm). cpu to GPU and network card to network card still will be lasers, the question is whether you can do core to core or CPU to ram with optics
But why are they talking about multicore fibres then? I would have expected ribbons. You might be right though.
> I would have expected ribbons.
The cable is just 2D parallel optical bus. With a bundle like this, you can wrap it with a nice, thick PVC (or whatever) jacket and employ a small, square connector that matches the physical scheme of the 2D planar microled array.
It's a brute force, simple minded approach enabled by high speed, low cost microled arrays. Pretty cool I think.
The ribbon concept could be applicable to PCBs though.
Re: TSMC bets on unorthodox optical tech
#64Earlier quoted context omitted.
short links it’s in the article
Ah I missed the 10m reference there. I'm not sure it makes more sense though. Typical intra-datacenter connections are 10s-100s of meters and use VCSELs, so introducing microleds just for the very short links instead of just parallelising the VCSEL connections (which is being done already)? If they could actually replace the VCSEL I would sort of see the point.
There's been a constant drum-beat that even intra-rack is trying to make its way to optical as fast as it can, that copper is more and more complex and expensive to scale faster. If we have a relatively affordable short range optical system that doesn't require heavy computational work to do, that sounds like a godsend, like a way to increase bits per joule while reducing expensive cabling cost.
Sure yes, optical might use expensive longer range optical today! But using that framing to assess new technologies & what help the could be may be folly.
Re: TSMC bets on unorthodox optical tech
#65Earlier quoted context omitted.
Mode dispersion is frequency dependent phase changes.
That's chromatic dispersion, mode dispersion is spatial "path" dependent phase changes. Vibration is actually somewhat more relevant because if it wasn't for that we could theoretically undo mode dispersion (we would need phase information though). That said all of that is irrelevant to what the previous speaker said, vibration induced phase variation as an impairment. Thats just not an issue, vibrations are way too…
How do the gravity wave optical paths solve the vibration issues? Couldn't TSMC do something similar?
Re: TSMC bets on unorthodox optical tech
#66> The transmitter acts like a miniature display screen and the detector like a camera. So if I'm streaming a movie, it could be that the video is actually literally visible inside the datacenter?
They story states there are 300 optical lines in the "fiberbundle." Let's assume this is arranged as 20x15 and the wavelength of the led is visible and bright enough to perceive. So if your unencoded, monochrome 20x15 movie was aligned on every frame and rendered at 10E9 FPS, then yes, your movie would be visible at the end of one of these cables through a magnifying glass.
Re: TSMC bets on unorthodox optical tech
#67Earlier quoted context omitted.
But why are they talking about multicore fibres then? I would have expected ribbons. You might be right though.
> I would have expected ribbons. The cable is just 2D parallel optical bus. With a bundle like this, you can wrap it with a nice, thick PVC (or whatever) jacket and employ a small, square connector that matches the physical scheme of the 2D planar microled array. It's a brute force, simple minded approach enabled by high speed, low cost microled arrays. Pretty cool I think. The ribbon concept could be applicable to P…
You might be right and they are talking about fibre bundles, but that that's something different to a multicore fibre (and much larger as well, which could pose significant problems especially if we are talking cm links). What isn't addressed is that leds are quite spatially incoherent and beam divergence is strong, so the fibres they must use are pretty large, coupling via just a connector might not be easy especially if we want to avoid crosstalk.
What I'm getting at is, that I don't see any advantage over vcsel arrays. I'm not convinced that the price point is that different.
Re: TSMC bets on unorthodox optical tech
#68Forgive the noob question but what stops us from making optical transistors?
I think the most fundamental reason is that there is no efficient enough nonlinearity at optical frequencies. So two beams(or frequencies in some implementation) tends not to affect each other in common materials, unless you have a very strong source (>1 W) so the current demonstrations for all-optical switching are mostly using pulsed sources.
As somebody who tried to do a PHD in optical communications, this is 100% correct.
I wonder if meta material might provide such nonlinearities in the future.
Re: TSMC bets on unorthodox optical tech
#69Earlier quoted context omitted.
> I would have expected ribbons. The cable is just 2D parallel optical bus. With a bundle like this, you can wrap it with a nice, thick PVC (or whatever) jacket and employ a small, square connector that matches the physical scheme of the 2D planar microled array. It's a brute force, simple minded approach enabled by high speed, low cost microled arrays. Pretty cool I think. The ribbon concept could be applicable to P…
You might be right and they are talking about fibre bundles, but that that's something different to a multicore fibre (and much larger as well, which could pose significant problems especially if we are talking cm links). What isn't addressed is that leds are quite spatially incoherent and beam divergence is strong, so the fibres they must use are pretty large, coupling via just a connector might not be easy especial…
> You might be right and they are talking about fibre bundles
The caption of the image of the cable and connector reads: "CMOS ASIC with microLEDs sending data with blue light into a fiberbundle." So yes, fibre bundles.
> I don't see any advantage over vcsel arrays
They claim the following advantages:
1. Low energy use
2. Low "computational overhead"
3. Scalability
There you are. All pretty simple.
I think there is use case for this outside data centers. We're at the point where copper transmission lines are a real problem for consumers. Fiber can solve the signal integrity problem for such use cases, however--despite several famous runs at it (Thunderbolt, Firewire)--the cost has always precluded widespread adoption outside niche, professional, or high-end applications. Maybe LED based optics can make fiber cost competitive with copper for such applications: one imagines a very small, very low power microLED based transceiver costing only slightly more than a USB connector on each end of such a cable with maybe 4-8 parallel fibers. Just spit-balling here
Re: TSMC bets on unorthodox optical tech
#70Earlier quoted context omitted.
You might be right and they are talking about fibre bundles, but that that's something different to a multicore fibre (and much larger as well, which could pose significant problems especially if we are talking cm links). What isn't addressed is that leds are quite spatially incoherent and beam divergence is strong, so the fibres they must use are pretty large, coupling via just a connector might not be easy especial…
> You might be right and they are talking about fibre bundles The caption of the image of the cable and connector reads: "CMOS ASIC with microLEDs sending data with blue light into a fiberbundle ." So yes, fibre bundles. > I don't see any advantage over vcsel arrays They claim the following advantages: 1. Low energy use 2. Low "computational overhead" 3. Scalability All of these at least pass the smell test. LEDs are…
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