Potentially this is a serious threat, and it's sometimes touted by critics who argue it's just emerging. Reality is a bit different though, Intel 100G transceivers have been around for some time, from an article more than a year ago:
IDF16 Intel is beginning volume shipments of its fabled Silicon Photonics networking technology, which uses light through thin glass fibers to replace copper wires. This tech can shuttle up to 100Gbps over 2km or more of cable that's just a few millimeters thick, creating a high-speed nervous-system for clusters and data centers. As its name suggests, Silicon Photonics uses patterned silicon to emit and receive precisely aligned data-carrying laser signals. These devices can be fabricated just like normal CMOS chips, meaning they should be relatively cheap and easy to make at high volumes. The dream is to embed this technology into processors and chipsets so they can shift data directly from their internal buses to external networks. That's the ultimate goal. Right now, though, we're just being offered discrete transceivers. You can basically whack a load of Intel's PSM4 and CWDM4 Silicon Photonics modules into a switch, or similar, and use them to network with other Silicon Photonics-equipped boxes, effectively running 100G Ethernet between devices. This technology has been in development for about 16 years.
Despite the fact that these were already shipping a year ago, Applied Opto was able to produce its highest growth during this period.