Data centers are facing competing challenges -- on one hand, they have to scale their networks to support more traffic. On the other hand, they have to scale without increasing power consumption, size or cost.
According to the Cisco Visual Networking Index (VNI), global IP traffic will increase more than 400% over the next five years. Data center operators need to find ways of scaling without consuming 400% more power, space or cost. They have to find better solutions.
Silicon photonics will play a major role in scaling of data centers. As the data center fabric moves from 10 Gb/s pipes to 40 and 100 Gb/s pipes, optical engines and optical transceivers based on silicon photonics will provide small, low-power, single-chip solutions. Integration is what sets silicon photonics apart from competing solutions. In silicon photonics, detectors can be monolithically integrated with WDM Demultiplexers. Integration of lasers, modulators, drivers, and WDM Multiplexers allow 100 Gb/s chip solutions to be less than a square centimeter.
Improved power consumption results from using new generations of CMOS technology as well as the efficiencies gained by integration. Lasers are more efficient when they are coupled by flip-chip bonded on chips designed to effectively capture their light. Silicon modulators allow for efficient CMOS drivers. Silicon detectors demonstrate superior performance with low power. A full 100 Gb/s optical transceiver, designed for data center links up to 10 km, would consume less than 5 watts, or one-fourth of the 20 watts consumed by many 100 Gb/s Ethernet transceivers.
Wave Division Multiplexing (WDM) is a method for transporting multiple wavelengths over a single optical fiber, greatly reducing the cost of the interconnect fabric. The IEEE 802.3ba standard for 10 km reach specifies that 100 Gb/s pipes use four wavelengths over a single SMF fiber. Future solutions that support 400 Gb/s, 800 Gb/s or 1 Tb/s will use more wavelengths. Kotura’s integrated WDM technology scales easily from 4 to 40 channels or more.