Intel Research announced significant progress in its integrated optoelectronics research, the next frontier in increasing the interconnect bandwidth of computing chips within and across data centers. This latest research, an industry-leading advance in multi-wavelength integrated optics, demonstrates an eight-wavelength distributed feedback (DFB) laser array fully integrated on a silicon wafer with output power uniformity of +/- 0.25 decibels (dB) ), the wavelength interval uniformity reaches ±6.5%, which is better than the industry standard.
Rong Haisheng, senior principal engineer at Intel Research, said: "This new study shows that uniformly dense wavelengths and well-adapted output power can be achieved at the same time, and most importantly, using existing Intel fabs. Production and process control technologies do this. As a result, it provides a clear path to mass production of next-generation optoelectronic co-packages and optical interconnect devices.”
Light sources produced using this new advance will have the performance required for future large-scale applications such as optoelectronic co-packages and optical interconnects that handle emerging network-intensive workloads such as AI and machine learning. Manufactured on Intel's 300mm silicon photonics process, the laser array paves the way for mass production and widespread deployment.
According to Gartner, by 2025, more than 20% of high-bandwidth channels in data centers will use silicon photonics, up from less than 5% in 2020. In addition, the size of the potential market for silicon photonics has also reached 2.6 billion US dollars. The need for low power consumption, high bandwidth, and fast data transfer has brought a simultaneous increase in the demand for silicon photonics to support data center applications and beyond.
Optical connections began to replace copper wires in the 1980s because the high-bandwidth optical transmission inherent in optical fibers outperformed the electrical pulses transmitted through metal cables. Since then, fiber optic technology has become more efficient due to reductions in component size and cost, leading to breakthrough advances in optical interconnect network solutions commonly used in switches, data centers, and other high-performance applications over the past few years. computing environment.
The side-by-side integration of silicon circuits and optics on the same package is expected to improve the energy efficiency and transmission distance of input/output (I/O) interfaces in the future as electrical interconnect performance approaches practical limits. These photonic technologies are implemented in Intel fabs using existing process technology, which means that their costs will be reduced when mass production is achieved.
The latest optoelectronic co-package solutions use dense wavelength division multiplexing (DWDM) technology, showing the promise of significantly reducing the size of photonic chips while increasing bandwidth. However, until now, it has been very difficult to fabricate DWDM light sources with uniform wavelength spacing and power.
This new development by Intel ensures that the light source has uniform output power while maintaining the consistency of wavelength separation, which meets the needs of optical computing interconnection and dense wavelength division multiplexing communication. Next-generation I/O interfaces using optical interconnects can be tailored for the extremely high bandwidth demands of future AI and machine learning workloads.
8 micro-ring modulators and optical waveguides. Each microring modulator is tuned to a specific wavelength (or "light color"). Using multiple wavelengths, each microring can modulate the light waves individually for independent communication. This method of using multiple wavelengths is called wavelength division multiplexing. (Image credit: Intel Corporation)
The eight-wavelength distributed feedback laser array was designed and fabricated on Intel's commercial 300 mm hybrid silicon photonics platform, which is used for volume production of optical transceivers. Based on the same tightly controlled process-controlled lithography technology used to manufacture 300 mm silicon wafers, this innovation represents a major leap forward in laser manufacturing capabilities in large CMOS fabs
8-Channel III-V/Silicon Hybrid Distributed Feedback Laser Array. By enabling matched power and uniform wavelength spacing, this innovation marks a major leap forward in the ability of large fabs to mass produce multi-wavelength lasers.
In this study, Intel used advanced photolithography to complete the configuration of waveguide gratings in silicon wafers prior to the III-V wafer bonding process. The technology improves wavelength uniformity compared to common semiconductor lasers fabricated in three- or four-inch III-V fabs. In addition, due to the high-density integration of the lasers, the array can keep the channel spacing stable even when the ambient temperature changes.
In the future, as a pioneer in silicon photonics technology, Intel will continue to work on various solutions to meet the growing demand for more efficient and more comprehensive network infrastructure. Currently, Intel is developing key building blocks for integrated optoelectronics including light generation, amplification, detection, modulation, CMOS interface circuitry and packaging integration.
In addition, many aspects of eight-wavelength integrated laser array fabrication technology are being used by Intel's Silicon Photonics Products Division to create future optical interconnect chips. This upcoming product will enable low-power, high-performance, multi-terabits per second interconnects between various computing resources including CPUs, GPUs and memory. Integrated laser arrays are the key to reducing size and cost for enabling large-scale manufacturing and deployment of optical interconnect chips.
