Opportunities

Supervisory Team: Prof Jayanta Sahu and Prof Johan Nilsson

Visible lasers are indispensable for applications such as display, underwater communication, microscopy, bio-photonics, optical storage, and materials processing. Often, high laser power is required. So far, the mainstream of high-power visible laser development has relied on frequency conversion techniques. However, often such systems are complex and require incorporation of bulk elements into the cavity, and thus are not suitable for robust, monolithic, devices. On the other hand, most rare earth (RE) ions exhibit absorption lines in the blue spectral region and fluorescence in the visible region. The progress in GaN-laser diodes (GaN-LD) covering wavelengths between 390 and 460 nm makes them promising pump sources for RE-doped solid-state lasers with direct emissions in the visible. To date, visible lasers utilising RE-doped fibres have been reported in fluoride glasses (such as ZBLAN) due to lower phonon energy than in oxide glasses, notably silica. However, fluoride glass fibres are known for their poor chemical durability, weak mechanical properties, higher background loss than silica fibres. Critically, they are also difficult to splice with silica fibre components. This makes it near-impossible to develop an all-fibre laser system and is a critical bottleneck to improved performance and commercial breakthrough.

This PhD project aims to investigate a route to high-power visible sources through cladding pumping of RE-doped silica fibres using GaN-LDs. The student will be involved in the design and fabrication of fibres doped with RE (such as Pr3+, Dy3+ and Tb3+) in modified silica glass hosts offering low phonon energy while maintaining the desirable characteristics of silica fibres. Additionally, the student will perform a detailed spectroscopic characterization of the fabricated fibres and can take part in the design and evaluation of high power visible fibre lasers.

 We are seeking PhD applicants with a background in physics/chemistry/engineering/materials science and with a strong interest in experimental work on optical fibre and/or laser technology for this ambitious project. Throughout the PhD, the candidate will have access to state-of-the-art fibre fabrication facilities and laboratories at the ORC.

 At the end of the PhD project, the student will have developed knowledge and skills in fibre fabrication, characterisation of doped optical fibres, and high-power fibre lasers.

https://www.southampton.ac.uk/study/postgraduate-research/projects/high-power-fibre-lasers-for-visible-wavelengths

Supervisor: Prof Jayanta Sahu and Prof Johan Nilsson

Specialty optical fibres form the foundation of numerous technological advancements across diverse fields, including high-power laser systems, advanced manufacturing, and optical communications. Each of these application domains depends critically on the development of fibres with tailored properties to satisfy increasingly demanding performance requirements. In particular, the power scaling of fibre lasers operating at eye-safe wavelengths (typically around 1.5–2 µm) is strongly influenced by the fibre design and the material properties of both the core and coating, which determine the limits of power handling and thermal management. Meeting these requirements demands advanced fibre fabrication processes that go beyond current industry standards.

In this PhD project, we aim to develop novel optical fibre materials and fabrication techniques for advanced erbium-doped fibres (EDFs) with tailored dopant profiles and large cores, supporting power scaling of pulsed and CW lasers and amplifiers at 1.55 µm. Special fibre coatings will be applied to ensure efficient thermal management at high average powers (several hundred watts) to enhance the robustness and reliability of fibre lasers for practical applications. The student will also perform a detailed spectroscopic characterisation of the fabricated fibres and participate in testing their performance in high-power lasers.

Supervisory Team: Dr Peter Horak, Prof Michalis Zervas

Join our interdisciplinary team at the University of Southampton to push the limits of high‑power fibre lasers. In this PhD, you will use advanced theory and computer simulations to uncover the fundamental processes that restrict laser performance, helping design the next generation of lasers for science, industry, and healthcare.

High‑power fibre lasers are transforming technology, from precision manufacturing to medical surgery. But as we push them to ever higher powers, new physical challenges emerge. This PhD project gives you the chance to work in a supportive, collaborative team to tackle those challenges head‑on, combining cutting‑edge physics with advanced computational tools.

The project is part of the High-Power Photonics (HiPPo) programme (https://www.hippo-laser.co.uk/), funded by the UK Research Council and based at the Optoelectronics Research Centre. Our goal is to develop the next generation of fibre lasers by combining novel fibre designs with intelligent control strategies — including machine learning — to achieve unprecedented power and beam quality.

Your role will focus on numerical simulations and theoretical modelling of light generation in large‑core, few‑mode and multimode fibres. You will explore how the spatial structure of the laser beam evolves under the influence of gain, losses, nonlinear effects, dispersion, and even thermal and acoustic interactions. These insights will directly guide experiments in our labs and at our industrial partners, giving your work immediate impact.

You will gain expertise in computational physics, nonlinear optics, and laser science. Alongside technical skills, you will develop problem‑solving, collaboration, and communication abilities that are highly valued in both academia and industry.

If you are excited by the idea of using simulations to unlock the physics behind some of the world’s most powerful lasers — and to shape technologies that will drive the future of manufacturing, medicine, and beyond — we would love to hear from you.

https://www.southampton.ac.uk/study/postgraduate-research/projects/computational-physics-of-high-power-fibre-lasers-from

Supervisory Team: Prof Johan Nilsson, Dr William Kerridge-Johns

This project combines state of the art optical fibre laser amplifiers with machine learning control to produce next-generation lasers for beam control such as beam shaping. These “smart” phased-array lasers promise to revolutionise materials processing and other important near-term and futuristic laser applications, including even starship propulsion! This modular and scalable approach offers rapid and flexible, unsurpassed, control of the beam shape and polarisation. Adding to this, computer control through neural networks and machine learning is now emerging as a means both to implement and to optimise the control offering a new range of capabilities in this rapidly developing field.

The Smart Fibre Optics High-Power Photonics (HiPPo) programme is a £6 million EPSRC funded 5-year programme pursuing fibre-based phased-array lasers at the Optoelectronics Research Centre, University of Southampton gow.epsrc.ukri.org/NGBOViewGrant.aspx?GrantRef=EP/W028786/1, www.orc.soton.ac.uk/news/7058. We are now seeking a PhD student to research advanced fibre amplifiers and beam combination concepts within this ground-breaking programme at the interface of physics and engineering. The general research area is laser physics & engineering, and specifically the building blocks and control needed for a phased-array laser. This involves fibre amplifiers with reduced noise, phase & polarisation control, as well as fibre nonlinearities and their mitigation in fibre laser systems at high intensities in the continuous-wave and/or pulsed regime. The control schemes will be developed and implemented with the assistance of machine learning specialists.

You will work in a world-leading team, measuring and optimising high-power fibre amplifiers that you design and build, e.g., with fibres fabricated in-house in ORC’s state-of-the-art cleanrooms. Throughout your PhD, you will have access to state-of-the-art laboratories at the ORC. At the end of your PhD project, you will have developed knowledge and skills in cutting-edge fibre and laser technology and advanced characterization techniques.

This project combines many highly-active research topics – phased array combination, machine learning, programmable structured light generation, multi-kW lasers – with a wide range of impact areas both in academic research and industry. If you are seeking an industrially-relevant PhD project with experimental focus and are interested in the rich physics challenges of high-power fibre lasers and phased arrays then this opportunity is perfect for you.

If you wish to discuss any details of the project informally, please contact Johan Nilsson (jn@orc.soton.ac.uk) or William Kerridge-Johns (W.R.Kerridge-Johns@soton.ac.uk)

Supervisory Team: Prof Johan Nilsson, Dr William Kerridge-Johns

This four-year PhD project, focussing on high-power laser architectures, is to contribute to a major Ministry of Defence (MoD) research programme intended to develop generation-after-next-technologies for applications in defence and security.

The project will be supervised by Prof Johan Nilsson (jn@orc.soton.ac.uk) and Dr William Kerridge-Johns (W.R.Kerridge-Johns@soton.ac.uk) at the University of Southampton with support and co-supervision by NKT Photonics (Dr Adam Devine). It will research coherent beam combination (CBC) of ytterbium-doped fibre laser amplifiers with multiple functionalities. This is in contrast to most of the current research on CBC lasers, which simply aims at increasing the power. The project will allow the student to acquire expertise in designing, constructing, operating, and characterising high-power fibre laser amplifiers, nonlinear fibre optics, and optical phase detection and control. The main objectives are:

• Experimental realisation and characterisation of high-power ytterbium-doped fibre laser amplifier with low phase noise and nonlinear phase distortion

• Realisation of multi-functional CBC laser

• Characterisation and optimisation of CBC laser

• Lab test on different targets.

The PhD project is part of a new MoD/EPSRC Energy Transfer Technology Skills and Training (S&T) Hub. The main aim of the S&T Hub is to train the next generation of leaders in energy transfer technologies relevant for defence and other related applications. The Hub is supported by MoD, Dstl, and UK companies working in the defence and security sector. The student will be part of a yearly cohort of 12 PhD students anticipated across a number of UK institutions. In addition to the project-specific research, specific Skills and Training Hub activities will take place online as well as face-to-face to facilitate cohort building and group learning exercises throughout the PhD programme. Each student will have an industrial partner and have opportunities to work with and train alongside experts from industry. Thus, the Hub offers individuals training for both a research and an industrial career.

The duration of the PhD is 4 years, and the start date is 1st October.

The PhD student will be physically based at the Optoelectronics Research Centre / Zepler Institute, University of Southampton (www.southampton.ac.uk/about/faculties-schools-departments/zepler-institute), where the majority of the research will take place. The ORC is one of the largest photonics research institutions in the world with over 350 members including PhD students. The ORC has a large cleanroom complex and a large number of well-equipped laser labs as well as very strong connections to industry and government research programmes and has spun out over ten companies.

The industrial partner, NKT Photonics (www.nktphotonics.com) has its headquarters in Denmark and will participate in the project via its UK operations in Hamble, within commuting distance from the University of Southampton. NKT Photonics is a leading supplier of high-performance fibre lasers and photonic crystal fibres. The main markets are Medical & Life Science, Industrial, Aerospace & Defence, and Quantum & Nano Technology. Products include supercontinuum white light lasers, low-noise fibre lasers, ultrafast lasers, and a wide range of specialty fibres. NKT Photonics will provide additional PhD supervision, hardware (when appropriate), a placement, and will be part of the larger S&T Hub community benefiting in the diverse academic and industrial network offered by the S&T Hub.

How to apply

Please contact the supervisor, Prof Johan Nilsson (jn@orc.soton.ac.uk) or Dr William Kerridge-Johns (W.R.Kerridge-Johns@soton.ac.uk) for application details and other queries, e.g., to arrange a visit.

Funding

This is a MoD/EPSRC Energy Transfer Technology Skills and Training Hub project. The duration of the PhD is 4 years. The funding will cover a stipend at the UKRI rate plus £2,000 ORC enhancement tax-free per annum (totalling around £21,000 for 2024/25, rising annually), tuition fees. Generous funds will be available for conference attendance and training, for students to travel to industrial partners and for longer placements with the industrial partner. The funding is for home students and applicants must be UK Nationals.

Eligibility

At least a UK 2:1 honours undergraduate degree, or its international equivalent, in a relevant science or engineering discipline. Candidates must be UK Nationals and be willing to apply for, and able to obtain, Baseline Personnel Security Standard (BPSS) clearance.

Equality, diversity and inclusion

The S&T Hub is committed to providing an inclusive environment in which diverse students can thrive. The Hub particularly encourages applications from women, disabled and Black, Asian and Minority Ethnic candidates, who are currently under-represented in the sector, and welcome all applicants regardless of their gender, disability, sexual orientation, and age. We will give full consideration to applicants seeking to study part time. The University of Southampton takes personal circumstances into account, has onsite childcare facilities, is committed to sustainability, and has been awarded the Platinum EcoAward. The Optoelectronics Research Centre has an Athena SWAN award.

Supervisory team: Dr Ben Mills, Dr James Grant-Jacob

Fibre lasers have already transformed the world. They are used across manufacturing for everything from the cutting of smartphone screens to the welding of electric car batteries. However, these fibre lasers simply follow a pre-programmed routine, and are not “smart”.

The next revolution is to go beyond the fixed fibre lasers that are currently used in manufacturing, and towards smart fibre lasers that automatically reconfigure and optimise in real-time for each application (and are fully integrated with the autonomous factories of the future).

In other words, the next revolution is the “self-driving” laser!

Your PhD will be focussed on the following applications: 1) convolutional neural networks and reinforcement learning for real-time control of lasers and laser machining, and 2) generative adversarial networks for simulating and optimising laser machining. Neural networks require large amounts of experimental data for training, and hence this PhD will therefore involve a mixture of experimental photonics, experimental automation, and programming and designing neural networks.

Supervisory Team: Dr Yongmin Jung and Prof. Michalis Zervas

Join our pioneering PHD project, “Advanced Beam Shaping for Next-Generation Fibre Lasers,” and be part of the future of laser technology. Fibre lasers are revolutionizing the field, providing unmatched stability without the need for moving parts or mirrors, making them an ideal solution for next-generation laser systems.

 Project Overview:

 This PhD opportunity is part of the UK’s EPSRC funded Programme Grant, HiPPo project (https://www.hippo-laser.co.uk/), which aims to revolutionize fibre lasers by integrating artificial intelligence (AI). As a key contributor in this cutting-edge project, you will work alongside leading researchers at the ORC and collaborate with global industry leaders, including Trumpf Laser, TWI, and Microsoft.

 Key Focus Areas:

 The project’s focus is on developing advanced fibre designs and novel devices for programmable spatial and polarization beam shaping, pushing the boundaries of fibre laser performance and versatility.

 As a PhD candidate, your contributions will include:

• Designing and implementing advanced beam and polarization shaping techniques to optimize fibre laser systems.

• Conducting experimental and simulation-based evaluations to validate and refine these technologies.

• Collaborating with interdisciplinary teams to transition your innovations into real-world applications.

• Exploring AI-driven control mechanisms for dynamic beam shaping and polarization modulation, enabling rapid, precise adjustments.

 Research Environment:

You’ll be part of the Pulsed Fibre Laser Group (~10 researchers) and the Hippo project (~25 researchers), both housed within the world-leading ORC. This dynamic and collaborative environment provides access to cutting-edge facilities, mentorship from academic experts, and engagement with industrial partners. You’ll work on ground-breaking research with real-world impacts, particularly in laser material processing.

 Join Us:

 If you’re eager to contribute to the future of laser technology and explore the powerful capabilities of fibre lasers, apply today and embark on a journey of innovation and discovery.

 Learn more about Dr. Yongmin Jung and the ORC research.

(https://www.southampton.ac.uk/people/5x5v8w/doctor-yongmin-jung#research)

Supervisory Team: Prof Jayanta Sahu and Dr Ben Mills

Specialty optical fibres are foundational to breakthroughs in fields spanning high-power lasers, advanced manufacturing, high-speed telecommunications, healthcare, and quantum technology. Each of these domains demands fibres with unique properties, such as power handling for industrial lasers, stability for quantum applications, or precision for healthcare diagnostics. However, optimising fibre characteristics through existing fabrication processes is complex and resource-intensive, especially as even the smallest variations in fabrication parameters can dramatically impact fibre performance.

This PhD project invites you to transform specialty fibre fabrication through the application of machine learning. By leveraging the predictive power of machine learning, you will be developing methods to model and fine-tune the intricate process variables, from dopant levels to temperature profiles and drawing conditions, enabling the production of fibres tailored to exact specifications. Imagine AI-driven insights that uncover brand new fabrication recipes and unlock the capability for real-time fabrication adjustments to create fibres optimised for each unique application.

You will apply machine learning techniques to understand how fibre fabrication steps, using methods such as Modified Chemical Vapor Deposition (MCVD), affect the final properties of fibres doped with rare-earth elements like Erbium, Ytterbium, and Thulium. Your objective will be to achieve superior optical properties, unmatched reliability, and exceptional yield, and ultimately unleash the production of fibres that push the limits of performance in lasers, improve transmission quality in telecoms, enhance imaging in healthcare, and meet the demanding requirements of quantum technologies. Your research will redefine fibre fabrication, setting the stage for the next generation of specialty optical fibres.

About the PhD Project

Are you passionate about developing novel research and keen to shape the future of laser-based energy transfer technologies? University of Southampton are recruiting a motivated PhD candidate to undertake an exciting project within the EPSRC Energy Transfer Technologies Doctoral Training Hub. As a student of the Hub, you will receive an enhanced stipend of £25,780 per year (£5,000 over the EPSRC standard), plus additional funds of £7,000 a year for travel, conferences and research equipment. This PhD project is co-funded by NKT Photonics.

 When a laser beam interacts with a target, the interaction often creates a plume. This can obscure the target, making it difficult to retrieve target information to determine how effective the interaction is. In case of a multi-functional laser, target information also helps in selecting the functionality. This applies to industrial laser processing as well as to defence and security applications.

 In this project, you will research both artificial-intelligence-based approaches to retrieving information from obscured interactions of targets with high-power laser beams, and the lasers you will use. As your research progresses, the lasers will gradually evolve in capability towards high-power multi-functional fibre arrays.

 The project will allow you to acquire expertise in artificial intelligence, lasers and laser arrays, and control. The main objectives are:

·       Realisation of an artificial intelligence (machine-learning-based) system for obscured target information retrieval.

·       The experimental realisation and characterisation of suitable lasers, including multi-functional and / or phased-array fibre lasers.

·       Lab tests on different targets.

The project will be supervised by Dr Ben Mills, Dr William Kerridge-Johns, and Prof Johan Nilsson at the University of Southampton with support and co-supervision from NKT Photonics (Dr Adam Devine). You will be physically based at the Optoelectronics Research Centre (ORC), University of Southampton (www.southampton.ac.uk/about/faculties-schools-departments/zepler-institute), where the majority of the research will take place. The ORC is one of the largest photonics research institutions in the world with over 350 members including PhD students. The ORC has a large cleanroom complex and a large number of well-equipped laser labs as well as very strong connections to industry and government research programmes and has spun out over ten companies.

The industrial partner, NKT Photonics (www.nktphotonics.com) is a leading supplier of high-performance fibre lasers and photonic crystal fibres. The main markets are Medical & Life Science, Industrial, Aerospace & Defence, and Quantum & Nano Technology. NKT Photonics will provide additional PhD supervision, hardware (when appropriate), a placement, and will be part of the larger Doctoral Training Hub community benefiting from the diverse academic and industrial network offered by the Hub.

 Key Details

·       Host Institution: University of Southampton

·       Industry Partner: NKT Photonics

·       PhD Duration: 4 years

·       Start Date: Around 1st October 2025

·       Enhanced stipend of £25,780 per year

·       Application deadline March 31 2025

The Hub

The Doctoral Training Hub specialises in developing research and training the next generation of leaders in energy transfer technologies for defence and related sectors. The successful candidate will be based at University of Southampton and throughout the PhD project will benefit from the support and expertise of our diverse academic community, a community of students working towards similar goals, and our specialist industrial network.

Why Join Us?

·       Industrial Collaboration: Each PhD student within the Hub is partnered with an industry collaborator, providing placement opportunities to work and train alongside industry experts

·       Comprehensive Training: The Hub offers a blend of academic and industrial training, preparing you for diverse career pathways in research or industry

·       Cohort Experience: Build your research network through inclusion in a vibrant cohort of PhD students that conduct research with academic leaders across leading UK institutions. Engage in online and face-to-face activities, including cohort-building events and collaborative learning exercises

·       Funding: A generous fully funded studentship (no fees and an enhanced personal stipend) with additional support for conferences, travel, training, consumables and extended placement with industry collaborators.

Please check the Hub website for further details at (link) Energy Transfer Technologies Doctoral Training Hub

Eligibility

PhD Candidates must hold a minimum of an upper Second-Class UK Honours degree or international equivalent in a relevant science or engineering discipline. Candidates must be UK Nationals and be willing to apply for and able to obtain Baseline Personnel Security Standard (BPSS) clearance.

Before you apply

We strongly recommend that you contact the supervisor(s) for this PhD project before you apply.

How to apply

Please contact the supervisor, Dr Ben Mills (bm602@orc.soton.ac.uk), Dr William Kerridge-Johns (W.R.Kerridge-Johns@soton.ac.uk), or Prof Johan Nilsson (jn@orc.soton.ac.uk) for application details or other queries, e.g., to arrange a visit.

Equality, diversity and inclusion

The Hub is committed to improving diversity within the sector and as such we aim to provide an inclusive environment in which all students can thrive. We particularly encourage applications from women, disabled and Black, Asian and Minority Ethnic candidates, and students from low-income / non-typical backgrounds to apply.  We can also consider part time PhD students. The University of Southampton takes personal circumstances into account, has onsite childcare facilities, is committed to sustainability, and has been awarded the Platinum EcoAward. The Optoelectronics Research Centre has an Athena SWAN award. We encourage and support talented individuals from various STEM backgrounds with ambition and an interest in making a difference. 

Funding Notes

This studentship is open to UK Nationals and is available for home students only. The generous funding package includes full tuition fees and an enhanced stipend of £25,780 per annum. Additional support is available for conference attendance, specialised training, travel to industrial partners, and extended placements with industry collaborators.

Application closing date

We welcome applications until March 31, 2025, although the position may be filled earlier.