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Ultrafast Optical Detector

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Re: Ultrafast Optical Detector

#11

Post by glumreaper »

mmmBacon wrote: post #3

While interesting this approach is not any faster than the Ge based photodiodes that we have currently. State of the art is ~-110GHz in Germanium Si photonics using standard fabs. This is only 50GHz.

The 50GHz or 20ps figure is actually the limit of the gear the scientists had available - from the paper at https://iopscience.iop.org/article/10.1088/1361-6463/ad9284/...

"the signal state transitions were established at less than 20 ps, which is comparable to the bandwidth limit of the oscilloscope utilized at 50 GHz. [...] the initial rise time constant may be shorter than the measurement limits of the oscilloscope."

Re: Ultrafast Optical Detector

#12

Post by mmmBacon »

glumreaper wrote: post #11
mmmBacon wrote: post #3

While interesting this approach is not any faster than the Ge based photodiodes that we have currently. State of the art is ~-110GHz in Germanium Si photonics using standard fabs. This is only 50GHz.

The 50GHz or 20ps figure is actually the limit of the gear the scientists had available - from the paper at https://iopscience.iop.org/article/10.1088/1361-6463/ad9284/... "the signal state transitions were established at less than 20 ps, which is comparable to the bandwidth limit of the oscilloscope utilized at 50 GHz. [...] the initial rise time constant may be shorter than the measurement limits of the oscilloscop…

Sure. But it’s on them to prove their claim that the device is faster and they haven’t done that. There are faster scopes and you can rent them.

Re: Ultrafast Optical Detector

#13

Post by mmmBacon »

frainfreeze wrote: post #6
mmmBacon wrote: post #3

While interesting this approach is not any faster than the Ge based photodiodes that we have currently. State of the art is ~-110GHz in Germanium Si photonics using standard fabs. This is only 50GHz.

Isn't state of the art already in the 300Ghz range?

Sure for InGaAs. The paper is claiming faster for AI so the relevant metric is to compare to what can be shipped today for such applications. To scale for AI we need devices that integrate with standard CMOS processes. More exotic materials can be integrated but they are not very practical for highly integrated systems. NVIDIA’s recent announcement for their copackaged optical switch is in a silicon only ecosystem.

Re: Ultrafast Optical Detector

#14

Post by jiggawatts »

momoschili wrote: post #5
mmmBacon wrote: post #3

While interesting this approach is not any faster than the Ge based photodiodes that we have currently. State of the art is ~-110GHz in Germanium Si photonics using standard fabs. This is only 50GHz.

A key here for western users is that it does not include Ge, which is notably a material that China has a stranglehold on.

Canada and Spain are major producers. America will be fine as long as they don’t start a trade war with every country all at once.

Oh.. ohhh… you threatened Canada with annexation too?

Oh boy.

Re: Ultrafast Optical Detector

#15

Post by momoschili »

jiggawatts wrote: post #14
momoschili wrote: post #5

Earlier quoted context omitted.

A key here for western users is that it does not include Ge, which is notably a material that China has a stranglehold on.

Canada and Spain are major producers. America will be fine as long as they don’t start a trade war with every country all at once. Oh.. ohhh … you threatened Canada with annexation too? Oh boy.

producing raw material does not mean you can process it.

The American defense branches have been searching for Ge-free alternatives for thermal optics, etc since during Biden's presidency. The trade war is significant, but does not change the calculus here.

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