Type: Theoretical, Experimental, Test/Characterisation

Decription/research Theme
Project has scope to range between purely theoretical to purely experimental depending on the interests and skillsets of the candidate. The scope can also evolve as the project progresses.
- numerical modelling of optical feedback and its effect on the laser power stability, combined with modelling design work to optimse the laser robustness to optical feedback, design of non-reciprocal lightpath designs
- design and/or fabrication and/or testing of lasers for improved optical feedback robustness
- design and build of optical bench test system for characterising reflection sources within HAMR sliders (Seagate would provide the test samples)
- fabrication of micron scale optical isolating structures (<50um)

Seagate Relevance
During writing operation in a HAMR hard disk drive the width of the written track is controlled by the power coming from the laser to the near field transducer in the writer structure. If the laser undergoes mode hopping (power fluctuations) due to optical reflections within the system the track will vary in an uncontrolled manner. Power increases risk encroaching on neighbouring tracks and loosing data, power reductions risk that the quality of the written track is poor as it is not as wide as intended. 

Wider Applications
Telecoms, datacoms, integrated Si photonics

Type: Theoretical, Experimental, Test/Characterisation

Decription/research Theme
Design and fabrication/test of a micron scale (<50um) optical switching structure which could be integrated into a HAMR read/write head

Seagate Relevance
In current HAMR read/write heads the laser must be turned on/off during write/idling modes. This causes a change in the level of heating within the head which can impact the quality of the writted track as the temperature stabilises once writing begins. Having an optical switch would allow the laser to be powered up and the temperature to stabilise before beginning to write by turning off the optical switch structure.

Wider Applications
Telecoms, data centre

Type: Theoretical, Experimental, Test/Characterisation

Decription/research Theme
Design and fabrication of prototypes of nanowire, plasmonic lasers which could be used in HAMR read/write heads for generating heat spots of 30nm diameter or less

Seagate Relevance
As HAMR hard drives look to scale to progressively narrower track widths the possibility of assessing alternate technologies to Near Field Transducers is of interest to Seagate

Wider Applications
Integrated systems, ultrasensitive sensing, data comms, nano photonic/nano electronic systems

Type: Theoretical, Experimental

Decription/research Theme
Design and fabrication of lasers with integrated optical coupling structures using non-Si materials. 

Seagate Relevance
Achieving required precision of alignment between the laser and the coupling structure in the read/write head is a challenge for HAMR. Having a laser with an integrated coupling structure may provide some relief in the required alignment tolerance.

Type: Experimental, Test/Characterisation

Decription/research Theme
Test and characterisation of GaAs laser performance response to external stress
Identify strategies for improving the robustness of the lasers to stress
Seagate can help provide laser samples for this testing

Seagate Relevance
During the operation in a HAMR hard drive the lasers can be exposed to external stresses. Having a laser which is more robust to these external stresses is desirable.

Type: Theoretical, with potential Experimental Elements

Decription/research Theme
Computational modelling study to examine what are the fundamental limits of how narrow a heat spot can be scaled to. Assessing multiple design options will be a requirement. Potential to fabricate samples to underpin modelling predictions.

Seagate Relevance
As HAMR technology evolves it is required to continually scale down the diameter of the heat spot generated so the written tracks are narrower enabling higher track density on the disk. An exploration of the limits of how low small a heatspot can be generated is of interest. 

Type: Theoretical, with potential Experimental Elements

Decription/research Theme
Computational modelling study to examine techniques to reduce the roundness of heatspots in a HAMR writer. Assessing multiple design options will be a requirement. Potential to fabricate samples to underpin modelling predictions

Seagate Relevance
As HAMR technology evolves it is required to continually scale down the diameter of the heat spot generated so the written tracks are narrower enabling higher track density on the disk. A square/rectangular heatspot profile instead of a circular profile is desirable for an improved quality of the written data track