Intel shows promising progress and key advances in integrated photonics for data centers

The effective management, control, and scaling of electrical input/output (I/O) are crucial in data centers today. Innovative ideas like Microsoft's Project Natick, which submerged a complete data center underwater, and optical computing and photonics, which aim to use light as a basic energy source in a device and for transferring information.

Building on this, at the Intel Labs Day 2020 conference today, Intel highlighted key advances in the fundamental technology building blocks that are a linchpin to the firm's integrated photonics research. These building blocks include light generation, amplification, detection, modulation, complementary metal-oxide-semiconductor (CMOS), all of which are essential to achieve integrated photonics.

Among the first noteworthy updates, Intel showed off a prototype that featured tight coupling of photonics and CMOS technologies. This served as a proof-of-concept of future full integration of optical photonics with core compute silicon. Intel also highlighted micro-ring modulators that are 1000x smaller than contemporary components found in electronic devices today. This is particularly significant as the size and cost of conventional silicon modulators have been a substantial barrier to bringing optical technology onto server packages, which require the integration of hundreds of these devices.

The key developments can be summarized as follows:

• Micro-ring modulators: Conventional silicon modulators take up too much area and are costly to place on IC packages. By developing micro-ring modulators, Intel has miniaturized the modulator by a factor of more than 1000, thereby eliminating a key barrier to integrating silicon photonics onto a compute package.
• All-silicon photodetector: For decades, the industry has believed silicon has virtually no light detection capability. Intel showcased research that proves otherwise. Lower cost is one of the main benefits of this breakthrough.
• Integrated semiconductor optical amplifier: As we focus on reducing total power consumption, integrated semiconductor optical amplifiers are an indispensable technology, made possible with the same material used for the integrated laser.
• Integrated multi-wavelength lasers: Using a technique called wavelength division multiplexing, separate wavelengths can be used from the same laser to convey more data in the same beam of light. This enables additional data to be transmitted over a single fiber, increasing bandwidth density.
• Integration: By tightly integrating silicon photonics and CMOS silicon through advanced packaging techniques, we can gain three benefits: (1) lower power (2) higher bandwidth and (3) reduced pin count. Intel is the only company that has demonstrated integrated multi-wavelength lasers and semiconductor optical amplifiers, all-silicon photodetectors, and micro-ring modulators on a single technology platform tightly integrated with CMOS silicon. This research breakthrough paves the path for scaling integrated photonics.

These results point towards the extended use of silicon photonics beyond the upper layers of the network and onto future server packages. The firm also believes that it paves a path towards integrating photonics with low-cost, high-volume silicon, which can eventually power our data centers and networks with high-speed, low-latency links.

“We are approaching an I/O power wall and an I/O bandwidth gap that will dramatically hinder performance scaling", said James Jaussi, who is the Senior Principal Engineer and Director of the PHY Lab at Intel Labs. He signaled that the firm's "research on tightly integrating photonics with CMOS silicon can systematically eliminate barriers across cost, power, and size constraints to bring the transformative power of optical interconnects to server packages.”