Recent news, DARPA (Defense Advanced Research Projects Agency) has successfully developed a new type of hollow-core photonic bandgap fiber, light can be 99.7% of the speed of light (or traditional quartz glass fiber 30% higher) for transmission along this material. In almost all of the fiber optic network, and the use of light is DARPA developed this optical fiber, the light can pass through the air gap, thus greatly improving the speed of the network, increase bandwidth and reach further through plastic or glass fiber transmission, distance.

Hollow fiber secret is the elimination of the cladding, taking instead a photonic crystal. When light passes through to reach the edge of the hollow, photonic crystals will bounce photons. Eliminated plastic / glass material, these hollow fibers can reduce the signal loss (to extend the distance between repeaters), improves the speed of light (specific plastic / glass faster about 30%) may also help reduce latency. According to DARPA reports, these are separated from each (single spatial mode) fiber can increase the bandwidth, to ensure that the polarization characteristics of light will not be affected (which is for sensing, security, communications, and other applications is very important).

DARPA about how to develop the details of the hollow fiber, we do not know, this may be because it is a military project and DARPA are not ready to disclose details because of it. This is the case of the University of Southampton in March on how to produce a hollow fiber is very similar.

DARPA is not the first developed hollow fiber, but it is developed in line with the US military's first application specification mechanism. You might want to clear these fibers are used in the data center and the Internet backbone, but the technology is actually as DARPA compact ultra-stable absolute reference gyroscope portion (COUGAR) for development projects. COUGAR aims to develop an extremely precise, invalid gyroscope for navigation (such as theater or indoor) in GPS. Eliminating the ring laser gyroscope complexity, the novel simply hollow photonic bandgap fibers should be used to manufacture extremely accurate fiber optic gyroscope.

Overall, the US military now has the ability to produce hollow fibers, but like the Internet originated in the ARPAnet as hollow fibers should eventually be able to show its mettle in a commercial environment.