Moore’s law could be saved by super-fast electronics and photonic tech

Moore’s law could be saved by super-fast electronics and photonic tech
There is a fundamental limit to how small transistors can become.

There is a fundamental limit to how small transistors can become. This simple fact threatens to end the geometric increase in computational power predicted by Moore’s law in the not too distant future. Knowing this, researchers have been scrambling to come up with the next big thing in computing before that happens, and silicon photonics has shown some real promise. Work out of IBM has laid the groundworkfor a faster breed of light-based computing, and now researchers from University of Colorado Boulder and MIT may have developed technology that will power future microprocessors. The optical components described in a pair of new studies can translate electrical signals into light, and they can be fabricated using existing facilities and technology.

Moore’s lawwas first described by Intel co-founder Gordon Moore in 1965, and it holds that the number of transistors that can be fitted in integrated circuits doubles about every two years. Even before we reach the limits imposed by atomic-scale miniaturization, Moore’s law is being threatened by the heat build-up on tiny, densely packed chips. Having too many electrical wires close together on chips also leads to crosstalk, or signal bleed.

Basically, the limiting factor in processor design has become the amount of electricity it takes to flip the transistors on and off. However, if electrical wires were replaced with light waves, these issues would be avoided completely and Moore’s law could continue to stay true, at least until a completely different technology takes over. The University of Colorado/MIT team has gotten one step closer to that goal by creating two new optical modulators that can detect electrical signals and then transmit the signal as an optical wave.

An optical communication circuit (also known as photonics) has the advantage of not producing waste heat when packed close together. The necessary fiber optic strands can also carry many different wavelengths of light while eliminating crosstalk. Sounds great, right?

No one is denying that photonics could be a boon to computing, but past versions of the technology would have required huge investments in new manufacturing processes. However, these new modulators require no change to existing processes.

Microprocessor makers don’t want to eat the cost of all the existing infrastructure, and that’s what sets this new research apart. One of the optical modulators designed by the team is fully compatible with the SOI CMOS manufacturing process, which is used to fabricate IBM’s Power7 and the Cell chips found in the PS3. Importantly, the second modulator works with the bulk CMOS tech used for building the majority of the world’s CPUs. Virtually all facilities can be easily updated to build integrated photonic chips with these modulators.

This work has the potential to bring the high bandwidth density and energy efficiency of photonics together with well-understood current manufacturing processes. It might finally make photonics a viable path forward as humanity continues to demand more computing power.

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