I'm not really against your point but I just quickly checked (and it agrees with my personal observation), iPhone have been the very most popular phone brand in China for many years and recently the market share grew beyond 25%. I would not say that's not big enough to matter.
You're confusing recent sales figures with overall market shares. Both Tesla and Apple use this neat little trick to their advantage, not just in China, but also in the EU and I'm sure in other places.
They both sell only like 2-3 models at a time, always heavily preferencing one of them in marketing, and then use that to claim they have the "best selling phone in the market". Which is true, but is not the same as having that percentage of the overall market share as a brand.
Nearly every Tesla sale is a Model Y sale, and nearly every Apple sale is an iPhone 17 sale. This does not apply to other brands such as BYD, Geely, Huawei, Oppo, (Samsung, Volkswagen,) where you can walk into a store and pick between about a dozen models targeting different niches.
On top of that, Apple just started selling iPhone 17, so yes, if you Google it, you find out that they've "reached 25% of the Chinese market" and not realise that this is what happens every Q4 simply because that's when they start selling new models. That is not the same as having 25% of the overall market share at all. Overall, both Tesla and Apple are around fifth most popular brands.
In that case some technical aspects needs rework...
Currently O1 visa being a nonimmigrant visa have no path to PR/citizenship (unlike H1Bs) and need annual renewal. This make it unattractive to "who possess extraordinary ability".
Yes, but even for people eligible for EB1A (it usually has a higher bar in practice, EB2/NIW is easier but way worse backlog), filing a (or according to some lesser stringent interpretation, having an approved) I-140, will make you have immigration intent and thus illegible for extension of any nonimmigration visa.
So you apply for green card and if you don't immediately get it (particularly because of the backlog for some countries), you have to leave the US.
(I'm not an immigration lawyer and these are only my personal interpretation).
That’s not the case. o1 is not officially classed as dual intent but it mostly functions that way.
“Labor Certification Exception:
Under the doctrine of dual intent, the fact that a U.S. employer has filed a labor certification, or an individual has filed a permanent residence petition on behalf of the non-immigrant, shall not be a basis for denying the O-1 petition, a request for extension of stay, admission to the US, or change of status for that O-1 non-immigrant.”
If you are okay with less smart smart watches, and okay with no hackability, Garmin should have a few with black and white display and >1 week battery life (even indefinite with sufficient solar).
I just searched and it appears that contrary to what I thought, it is possible to individually acquire Windows 11 Enterprise (IoT or non-IoT) LTSC licenses from some redistributors.
The price varies a lot from suprisingly cheap ($7.7, is buykeysoft.com legit?) to a bit expensive but acceptable (~200 CHF). I'll definitely use these when I'm setting up my new desktop in the future.
The issue I tend to have with redistributors is that ultimately: it might not end up being a valid license.
What's the difference between outright piracy and buying an invalid (but functioning) CD key? Legally: nothing.
If a key is minted to be used only in certain areas or for certain purposes (healthcare, education) and it's sold to me- I don't have a right to use it.
That's the really annoying thing about these CD key online things, they give the illusion of doing the right thing but ultimately it's the same issue.
Truthfully I don't think any of us will be audited, but it's an annoying situation I continually see. People think just because money changed hands that they're legal.
I was thinking a lot about it as I don't want to put anything illegal on my computer. OTOH, the only way to buy an older version (in my case, Office 2016 for Mac) is to use a reseller. I try to do a research, I try to find a reputable one, I receive an invoice, I install and active the software, it works, but in the end it's as you say - there is no certainty at all.
But in the end I'm fine with that. First, the vendor is no longer selling this product, second, there is only that much one can do.
Chinese have developed a significant amount of sophisticated tools countering internet censorship. V2ray as far as I recall is the state-of-the-art.
To use them, one need to first rent a (virtual) server somewhere from a foreign cloud provider as long as the payment does not pose a problem. The first step sometimes proves difficult for people in China, but hopefully Indonesia is not at that stage yet. What follows is relatively easy as there are many tutorials for the deployment like: https://guide.v2fly.org/en_US/
I guess they are doing direct modulated IMDD for each link so the DSP burden is not related to the coherence of diodes? Also indeed very short reach in the article.
The problem with both leds and imaging fibres is that modal dispersion is massive and completely destroys your signal after only a few meters of propagation. So unless you do MMSE (which I assume would be cost prohibitive), you really can only go a few meters. IMDD doesn't really make a difference here.
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
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.
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.
> 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 indeed quite efficient relative to lasers. They cite about an order of magnitude "pJ/bit" advantage for the system over laser based optics, and I presume they're privy to vcsels. When you're trying to wheedle nuclear reactor restarts to run your enormous AI clusters, saving power is nice. The system has a parallel "conductor" design that likely employs high speed parallel CMOS latches, so the "computational overhead" claim could make sense: all you're doing is latching bits to/from PCB traces or IC pins so all the SerDes and multiplexing cost is gone. They claim that it can easily be scaled to more pixels/lines. Sure, I guess: low power makes that easier.
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
Aren't they also claiming this is more reliable? I'm told laser reliability is a hurdle for CPO.
And given the talk about this as a CPO alternative, I was assuming this was for back plane and connections of a few metres, not components on the same PCB.
> Aren't they also claiming this is more reliable?
Indeed they do. I overlooked that.
I know little about microLED arrays and their reliability, so I won't guess about how credible this is: LED reliability has a lot of factors. The cables involved will probably be less reliable than conventional laser fiber optics due to the much larger number of fibers that have to be precision assembled. Likely to be more fragile as well.
On-site fabricating or repairing such cables likely isn't feasible.
I understand that CPO reliability concerns are specifically with the laser drivers. It's very expensive to replace your whole chip when one fails. Even if the cables are a concern (I've no idea), having more reliable drivers would still be preferable to less reliable cables, given how much cheaper/easier replacing cables would be (up to a point, of course).
LDO is just integration. It certainly has value: integration almost always does. So it's clearly the obvious optimization of conventional serial optical communication.
This new TSMC work with parallel incoherent optics is altogether distinct. No DSP. No SerDes. Apples and oranges.
Ok, but I'm just after solutions to problems I have talking to other chips. I don't mind what's novel and what's optimisation. Whatever is adopted, in either case it's a step-change from the past 20 years of essentially just copper and regular serdes in this space.
And I'm not sure how much of this is actually TSMC's work, the title is misleading.
Edit: actually, they are working on the detector side.
we use borosilicate fibers that are used for illumination applications. You might have seen a bundle in a microscope light for example. And they are incredibly robust compared to single mode fibers. Note the very tight bend angle in the picture - that's a 3mm bend radius. Imagine doing that with a single mode fiber!
See my other comment about non-datacenter applications. There is a serious opportunity here for fixing signal integrity problems with contemporary high bandwidth peripherals. Copper USB et al. are no good and in desperate need of a better medium.
The fiber cables we use are basically 2D arrays of 50um thick fibers that match the LED and detector arrays. We've made connectors and demonstrated very low crosstalk between the fibers. Advantage over VCSELs is much lower power consumption overall, much lower cost (LEDs are dirt cheap and extremely high yield), because we are blue light, the detector arrays are much easier and can be modified camera technology, and most importantly, much better reliability. VCSELs are notorious for bad rel.
This might be the breakthrough we also have been working on [1] for over 20 years. It would be even better if Avicena wouldn't drive the led array and detector array with high power 10 Gbps SerDes. Even better if you align a blue led array with lenses to a
detector array on a second chip: free space optics [2].
I would love to join you at Avicena and work on your breakthrough instead of just acquiring the IP from you in a few years.
Just wanted to clarify that I don't necessarily doubt that you have a use case (BTW partnering up with someone like intel or so on for optical thunderbold or similar like someone else mentioned would be very interesting as well), you definitely have people who know what they are doing. I thought the ieee article however does give the wrong impressions as it mainly compares with the wrong thing, somebody here (maybe you?) was also saying 50 mu m fibres are much easier to couple into than SMF, which is correct, but also not relevant because VCSEL links typically use OM fibre with 50-60 mu m core diameters as well.
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.
No this is not an engineering issue, it's a problem of fundamental physics. Photons don't interact easily. That doesn't mean there are not specialised applications where optical processing can make sense, e.g. a matrix multiplication is really just a more complex lens so it's become very popular to make ML accelerators based on this.
Contrary to the prior commenter, there is definitely significant engineering going toward this, but it's not clear or likely that photonic computing will supplant electronic computing (at least not anytime soon), but rather most seem to think of it as an accelerator for highly parallel tasks. Two major ways people are thinking of achieving this are using lithium niobate devices which mediate nonlinear optical effects via light-matter interaction, and silicon photonic devices with electrically tunable elements. In the past there was a lot of work with III-V semiconductors (GaAs/InAs/GaN/AlN etc) but that seems to have leveled off in favor of lithium niobate.
Photonics has definitely proved itself in communications and linear computing, but still has a way to in terms of general (nonlinear) compute.
Not an expert in communications.
Would the SerDes be the new bottleneck in the approach? I imagine there is a reason for serial interfaces dominating over the parallel ones, maybe timing skew between lanes, how can this be addressed in this massive parallel optical parallel interface?
That's a big part of it. I remember in the Early Pentium 4 days, starting to see a lot more visible 'squiggles' on PCB traces on motherboards; the squiggles essentially being a case of 'these lines need more length to be about as long as the other lines and not skew timing'
In the case of what the article is describing, I'm imagining a sort of 'harness cable' that has a connector on each end for all the fibers, and the fibers in the cable itself are all the same length, there wouldn't be a skew timing issue. (Instead, you worry about bend radius limitations.)
> Would the SerDes be the new bottleneck in the approach
I'd think yes, but at the same time in my head I can't really decide whether it's a harder problem than normal mux/demux.
SerDes is already frequently parallelised. The difference is you never expect the edges or even the entire bits to arrive at the same time. You design your systems to recover timing per link so the skew doesnt become the constraint on the line rate.
one can implement SerDes at any point of the electro-optical boundary. For example, if we have 1 Tbps incoming NRZ data from the fiber, and the CMOS technology at hand only allows 10 GHz clock speed for the slicers, one can have 100x receivers (photodiode, TIA, slicer), or 1x photodiode, 100x TIA + slicer, or 1x photodiode + TIA and 100x slicers. The most common id the last one, and it spits out 100x parallel data.
Things get interesting if the losses are high and there needs to be a DFE. This limits speed a lot, but then copper solutions moved to sending multi-bit symbols (PAM 3, 4,5,6,8,16.. ) which can also be done in optical domain. One can even send multiple wavelengths in optical domain, so there are ways to boost the baud rate without requiring high clock frequencies.
>serial interfaces dominating over the parallel ones
Semi-accurate. For example, PCIe remains dominant in computing. PCIe is technically a serial protocol, as new versions of PCIe (7.0 is releasing soon) increase the serial transmission rate. However, PCIe is also parallel-wise scalable based on performance needs through "lanes", where one lane is a total of four wires, arranged as two differential pairs, with one pair for receiving (RX) and one for transmitting (TX).
PCIe scales up to 16 lanes, so a PCIe x16 interface will have 64 wires forming 32 differential pairs. When routing PCIe traces, the length of all differential pairs must be within <100 mils of each other (I believe; it's been about 10 years since I last read the spec). That's to address the "timing skew between lanes" you mention, and DRCs in the PCB design software will ensure the trace length skew requirement is respected.
>how can this be addressed in this massive parallel optical parallel interface?
From a hardware perspective, reserve a few "pixels" of the story's MicroLED transmitter array for link control, not for data transfer. Examples might be a clock or a data frame synchronization signal. From the software side, design a communication protocol which negotiates a stable connection between the endpoints and incorporates checksums.
Abstractly, the serial vs. parallel dynamic shifts as technology advances. Raising clock rates to shove more data down the line faster (serial improvement) works to a point, but you'll eventually hit the limits of your current technology. Still need more bandwidth? Just add more lines to meet your needs (parallel improvement). Eventually the technology improves, and the dynamic continues. A perfect example of that is PCIe.
They are doing 10 Gb/s over each fibre, to get to 10 Gb/s you have already undergone a parallel -> serial conversion in electronics (clock rates of your asics/fpgas are much lower), to increase the serial rate is in fact the bottleneck. Where the actual optimum serial rate is highly depends on the cost of each transceiver, e.g. long haul optical links operate at up to 1 Tb/s serial rates while datacenter interconnects are 10-25G serial AFAIK.
For a foreigner living outside of the US but interested in immigrating to the US in the longer term. Is it possible file the I-140, and while the application is being processed (or waiting for the priority date) apply for another nonimmigrant visa (B, F or J) for short term visit? Is it likely the application will be denied because of the "immigration intent" after filing the I-140?
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