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Comment Re:Big deal (Score 1) 38

It's great work, very fascinating. The speed can probably improved up to a point but it could be a valuable technology based only on the energy per bit switching event, since this sets the energy limit for a given piece of computation.

A more important challenge is integrating this into a circuit and figuring out how to get electrical signals into optical switches based on the output of an optical switch. Transistors are great since they are electrical input and output, and with complementary logic they only draw a leakage current except while they are switching. But a voltage controlled optical/plasmonic switch is strictly speaking a transducer and so you need it paired with the inverse transducer element to create cascadable elements. And you need something supplying the light. And while there is a small switching element there is a (comparatively) huge waveguide feeding structure. So solving these issues and making sure that you don't get huge energy losses when you add the pieces surrounding the switch element, and figuring out how to combine large numbers of elements onto a small chip is the bigger challenge for bringing this into a computing application. Or maybe it can make a very energy efficient optical modulator, not used for computation.

Comment Re:Physics puts enormous limits on using 30-300GHz (Score 1) 33

Making a power amplifier to produce even one Watt of signal at 75 GHz is a million-dollar project. In short, it's not likely to be mainstream for at least ten years.

I work in mm-wave semiconductors and you might be pleased to find out that you're high by a factor of over 100 on price :)

Power amplifier chips have no need to be cryogenically cooled like the ultra-low noise temperature amplifiers used in radioastronomy receivers. A few years ago you could pay about $10k per watt of packaged, power combined Gallium Arsenide amplifiers up to ~30 watts of power, and I understand that today the price is less than half of that. GaAs is not exotic, fully fabricated 6" wafers for the cell phone market apparently cost under $1,000 each (and each chip just a few square mm of that wafer). If you need really high powers vacuum tubes are available at ~100 watt output power levels at a similar price per watt.

Those prices are of course really high, but that's in large part because the market is tiny and a lot of these amplifiers are basically one-offs built for a specific customer and application. With volume production prices will drop dramatically.

Gallium Nitride is capable of per-chip output powers several times larger than Gallium Arsenide, in fact Fujitsu just last month unveiled their own over 1 watt GaN amplifier operating at 86 GHz. Other companies have had 1-2 watt output chips a few years ago, and at higher efficiencies, but I think Fujitsu might be better positioned to commercialize their technology.

Comment Re:$231 million? (Score 1) 139

Similar thing happens with the construction in some public universities. Because of the complexity of bidding on projects, the documentation required before, during, and after project completion, heavy oversight from the Campus's own construction department (and a hefty overhead percentage charged to pay for said oversight), and inevitable change orders throughout the project because of committees wanting new things after already accepting a design and/or construction bid, I have heard that construction costs 2-3x as much at some universities as similar projects taken on by (competent) private companies.

Comment Re:Great until we run out of Helium (Score 1) 145

The market will provide. My understanding is that the US government is selling off its helium reserve which lowers prices and makes it uneconomical to extract a lot of it at the moment. When the reserve is depleted and prices raise back up to natural levels then collection will increase.

Comment Re:Political bullshit that has nothing to do with (Score 1) 369

You do realize that oil is a global commodity and there are literally hundreds of sources for it around the world, and that one country buying from Canada will not affect the prices for other countries unilaterally?

If refineries in the US start talking larger deliveries of Canadian crude, and the product of that refinement is going to be exported, then yes it can increase oil prices in the US because it represents a loss of refinement capacity dedicated to the US market. Refineries having problems affecting capacity leading to regional fluctuations in oil prices is a very common news story.

I'm not saying that this is necessarily a bad thing - if it's good for the US refinery business and they may add capacity over time which might give us a bigger buffer to handle refinery problems. Or it might not, I'm not an oil futures analyst. But it could certainly raise US oil prices at least temporarily.

Comment Re:You keep using that word. I don't think it mean (Score 1) 346

And how could they actually see the difference - forwarded data to PC versus used in the phone?

The phone makes the distinction because the phone sets up the tethered access point. Unless the user installs apps to get around this, which is what they did.

As soon as the data traffic has reached the phone it's up to the phone owner to do whatever he/she want.

Not if the phone owner wants to abide by the contract they agreed to in their cellular plan. T-Mobile wants to have additional control on tethered data because it is easier to use more data on a computer than on a phone, typically.

Not saying it's right or wrong, but that's the reasoning for limiting tethered data, and a customer needs to go out of their way to get around the limits that they agreed to in the cell phone plan terms.

Comment Re:Wow! (Score 1) 274

My problem with this kind of compensation scheme is twofold:

1) Investment managers don't even need to beat the market to get a bonus. If the market as a whole goes up then the investment managers get rewarded, even if their performance lags the market as a whole!

2) By rewarding gains but not penalizing losses you get a scenario where investment managers may be incentivized to take greater risks for the possibility of bonuses since they are not penalized for 20% of the losses. In essence, they may benefit from increased variance.

But I'll admit that I don't know if providing a fee with no bonuses to the investment manager or managing company ends up being a better strategy.

Comment Re:What goes around, comes around (Score 2) 90

Back in the 80's they would have been talking mainly about Gallium Arsenide (GaAs) which is what enabled cell phone and wifi transceivers. Now silicon is taking much of that market back from GaAs since silicon has improved to the point where it is good enough for these applications and can be cheaper and more highly integrated.

Gallium Nitride got going in the 90's, being explored by the DoD for radar and other radio applications. In fact one of the goals was to just get better solid state drive amplifiers to drive really high power vacuum tubes. Now GaN is good enough to drive the radar directly (though tubes can still do some things that GaN can't).

Now that GaN has matured enough people are taking it into the power conversion market. EPC and Transphorm are two such companies with released devices.

Comment Re:Denser chips (Score 5, Informative) 90

Gallium Nitride (GaN) isn't going to be used for digital computer, rather it is being targeted towards power conversion circuits such as computer power supplies and motor drives. For these applications gate lengths are typically of the order of 1 micron which is child's play compared to the ultra scaled digital devices.

GaN's circuit size advantage is only partially from the reduced size of the chip, it is the fact that the GaN transistor can operate faster while producing less heat in power conversion circuits. Since the transistor produces less waste heat the heatsink is smaller. Since it can switch faster it means that the inductor and capacitor filter components can be smaller. All of this translates into much higher power per volume.

Comment Re:Something wrong there (Score 1) 549

Did you watch the linked video? The Google car appears to smoothly come to a stop at a traffic light with two stopped cars ahead of the Google car. There's no "body language" that contributed to this situation, just a following driver who didn't stop in time at a red light with stopped cars ahead. It happens every day.

If you are about to slow down,... let off the gas a little bit

This is actually worse telegraphing than a smooth deceleration with the brakes because by just letting off the gas you start slowing down with no brake light signal to following drivers. It takes more time and brain power to parse that somebody is decelerating when they just let off the gas. At least for me when I'm following you.

If the Google car just enters a slowing-down event, it might be undetectable.

Again: brake lights.

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