EPSRC Centre for Doctoral Training in Photonic Integration and Advanced Data Storage

Information technology and the Internet are central to our society and these technologies require storage of digital information on an exponentially increasing scale. There are two principal types of storage: traditional hard disk drives (HDD) that provide high density storage at low cost, and solid state drives (SSD) that offer less capacity at greater price, but are more power efficient and have no mechanical parts. While most personal computing and related electronic devices are migrating to SSD the need for HDD is also increasing - in a local context (e.g. personal TV and video recorders) and also remotely, particularly in cloud computing. Cloud computing is a rapidly growing sector, where already almost all of e-commerce and the internet and much of the engineering industry rely on data farms filled with large numbers of 'server' computers using HDD to store information. These data range from personal information such as bank details and social media through to environmental data, data related to health and company and institution specific data. Cloud computing accounted for 25% of storage use in 2010 and by 2020 it will account for >60% - a server is required for every 600 smartphones or 120 tablet computers. As a result, HDDs of ever increasing capacity are required.

Due to the limitations of current materials, a new technology will be needed to increase the density of magnetic data recording at the present rate, and it envisaged this technology will be heat-assisted magnetic recording (HAMR). HAMR will require the integration of photonic components such as lasers, waveguides and plasmonic antennas within a magnetic recording head.

HAMR will only be successful if it can be deployed as a low-cost manufacturable technology. Its successful development will therefore drive low-cost photonic integration and plasmonic technology into other industries and applications. The CDT will address the challenge with a critical mass of partners from universities and industry to meet this challenge and undertake the training of successive cohorts of research students in a set of cognate technical topics:
- Ultra-reliable semiconductor lasers operating in hostile environments (the laser may have to operate at temperatures of 100 degree C)
- Low cost planar lightwave circuit (PLC) platforms and laser and antenna coupling schemes, suitable for volume manufacture
- Novel nanoplasmonic antennas capable of operating in extreme environments (200-300 degree C and pressures up to 10 atm. at the disk/head interface)
- Advanced materials for magnetic recording
- Atomic scale analysis techniques
This suite of technologies must be highly manufacturable and suitable for heterogeneous integration in a rugged platform. The successful development of HAMR technology will see a paradigm shift in the performance of data storage devices but the low-cost ruggedized heterogeneous integration technology will also be applicable in multiple markets. Although the HAMR environment is particularly harsh, many other consumer and society driven applications (such as widely deployable high speed internet) also require operation in harsh environments.

Our industry partners have identified that distributed working is an element missing from existing doctoral training. Much R&D in cutting edge technology is undertaken collaboratively across geographically separated sites because of the need to thread together expertise and capability that is often not co-located. It is important that doctoral students gain experience in this way of working and develop the skills and strategies to become adept and effective in this environment.

The technical capability required to address the range of photonic and heterogeneous integration requirements for advanced data storage does not reside within one single University in the UK and therefore collaboration across the partner university sites provides the vehicle for delivering training in distributed working.

Academic
The development of a cohort of fifty young doctoral researchers who in the programme will acquire a unique set of technical abilities allied with working practice, managerial and enterprise skills.
The research to be undertaken by the cohort incorporates areas such as photonics, meta-materials, functional materials and plasmonics. The research programme is targeted at developing a suite of integrative technologies that address the requirements of heat assisted magnetic recording (HAMR). HAMR requires a highly manufacturable, rugged heterogeneous integration platform, encompassing semiconductor lasers, passive waveguides, rugged plasmonic devices and advanced magnetic materials. The successful development of HAMR will see a paradigm shift in the performance of data storage devices.
Advances in the above areas will see the CDT, supervisory staff and cohort develop a reputation and output profile that will lead to further basic research funding in the Universities and to the launch of academic careers for some of the cohort through attaining post-doctoral positions.

Industrial
The CDT brings together key companies who could form a complete UK manufacturing supply chain for HAMR technology. These companies include as founder partners - IQE as a supplier of custom epitaxy, Oclaro for volume laser production and Seagate for volume manufacturing of magnetic recording heads.
The CDT will result in the development and adoption of this low-cost heterogeneous integration technology, a technology than can also be applied in multiple markets. Although the HAMR environment is particularly harsh, many other consumer and society driven applications (such as widely deployable high speed internet) also require operation in harsh environments. The technology developed here will allow migration away from traditional expensive solutions such as laser packaging in temperature stabilised, gold plated, hermetic boxes.

Societal
The Engagement & Outreach Committee of the CDT along with the leadership, supervisory staff and cohort will proactively engage with the wider society to raise awareness of the underpinning science and engineering. The CDT will demonstrate how it supports a high technology manufacturing supply chain in which UK activity has a global significance and brings benefit to a large part of society. Notwithstanding other commercial applications that our end-users have, we will be able to highlight how the integration of underpinning science and engineering lies at the core of much high technology.

Economic.
Our key partner has a significant presence in the UK through employment of some 1500 people in manufacturing and R&D. The current operation is centred on a capital base of some £1.5B and contributes around £100M GVA p.a. to the UK economy. The societal need for increased data storage places this operation as a nexus of the global economy and consequently offers significant supply chain opportunity for the UK. The need to develop HAMR requires the development of the integration technology that lies at the core of our CDT. The outcomes of the CDT will inform future decisions that will underpin further corporate investment of £10M's to equip the partner and to recruit the necessary staff. We note that the key partner, in their letter of support, could absorb the entire cohort into employment over the next few years. Our other project partners will also benefit beyond HAMR. As examples; CST Global would apply novel lasers and integrated solutions to niche applications, Kelvin Nanotechnology will be able to exploit new integration expertise, OIPT need a pipeline of trained personnel that is currently not available in the UK, JEOL and FEI have interests in new imaging and metrology associated with new material and integration technologies. All the partners would benefit from a flow of PhD graduates trained in advanced material assessment.