Composite material hollow core fibres for active photonics

Optical fibres form the physical layer of the remarkable >2 billion km long global telecommunications network, currently bifurcating and expanding at a rate >Mach 20, i.e. over 14000 ft/sec (source: Corning.com). They are also an essential component in devices such as lasers, optical amplifiers, gyroscopes, gas or environmental sensors, as well as a means to locally link devices and applications. One of the most significant advances in optical fibre technology over the last 20 years has been the realisation of silica fibres that are able to internally guide light using an air core rather than glass. Hollow Core Photonic Bandgap Fibres (HC-PBGFs) were first demonstrated in the late 1990s. Researchers uncovered remarkable physics, demonstrating that these fibres were able to transmit high optical powers, ultrashort pulses and wavelengths regions including the mid-IR which cannot be delivered through standard optical fibres. A number of important applications can be targeted within these wavelength regions and in particular mid-infrared light can be used to detect a wide range of chemical, biological or physical species (e.g. to identify explosives on surfaces, hazardous air pollutants in the environment, or biomarkers in the breath of a patient).

The last few years have seen dramatic progress in the area of hollow fibres and in particular the development of a competing technology to photonic bandgap fibres based on a much simpler optical design, which are far easier to fabricate for both short and long wavelength transmission and have been demonstrated to have a greatly reduced overlap between the light travelling within the fibre and the silica forming the cladding. This novel form of hollow core optical waveguide is known as the anti-resonant fibre. In this proposal, we will demonstrate an innovative waveguide platform based on composite material hollow core fibres which are able not only to transmit optical signals with low attenuation over a broad wavelength range of operation, but can also actively manage and control the transmitted signals, through modulation, amplification or light generation and frequency conversion.

The UK is a major manufacturer of photonic materials and devices as well as being a major industrial user of photonics in key application sectors such as manufacturing, medicine, datacomms and defence. Therefore, improvements in fundamental optical fibre properties, such as those detailed in this research programme, will yield substantial system performance/cost benefits, potentially leading to huge commercial benefits to early adopters.

Economic impact: The primary impact of our project will be the creation of processes that enable rapid commercialisation of emerging photonics technologies. Near-market prototypes of CM-RARF technology for example, would be readily exploitable for future mid-infrared internet telecommunications where the fibres not only passively transport light, but also actively process the optical data streams. This will result in new products/services and new UK manufacturing jobs and a net contribution to the creation of wealth. Evidence for the potential economic impact of our research program comes from the significant interest that our research program has attracted from the industry, even at this early TRL level.

Social impact: The innovative waveguide platform we will develop could have significant impact on healthcare technologies by enabling high performance devices that operate at biological relevant wavelength regimes e.g. 3000nm, where very strong absorption by H2O allows for surgical procedures on both hard and soft tissue with minimal heat related side effects. We also anticipate augmenting the burgeoning digital economy sector via the development of novel amplifiers for low latency optical data transmission. Other sectors that could benefit from our research include quantum technologies, for more secure communications in banking and national security, which will contribute to the improvement of the general quality of life.