UV light sources based on solid silica fibres

Lead Research Organisation: University of Southampton
Department Name: Optoelectronics Research Centre

Abstract

Optical fibre lasers offer significant benefits in comparison to other laser sources, such as extremely low thermal lensing, extraordinary good beam quality and very high plug efficiency. Optical fibre lasers have worldwide sales in excess of $300M and a predicted annual growth rate of 20-40%, thus are rapidly replacing other types of more conventional lasers. Indeed, the increasing deployment of high power fibre lasers in manufacturing has improved consumption efficiency.

Up to date only near-IR sources have been manufactured in fiberized forms. The challenge is to develop new fiberized sources in the mid-UV. The successful manufacture of optical fibre lasers would have numerous applications which include, amongst others, water purification, insulators (such as plastics or glass) marking and processing, explosive detection, forensics and counter measures.

This projects aim to demonstrate the possibility to use solid silica fibres to efficiently generate light in the UV. The proposed programme spans from the manufacture of specialty silica fibres transparent to the UV, doped with novel lasing elements, the design of fiberized laser pumps, and their combination in suitable systems to produce a new generation of affordable higher performance lasers.

A variety of lasers with wavelength in the range 170nm to 330 nm will be developed and their applications in Raman spectroscopy and supercontinuum generation will be investigated.

Planned Impact

This project aims to demonstrate the possibility to manufacture UV light sources from solid silica optical fibres. The main application of this proposal outcome resides in the industrial exploitation for the many applications where high intensity and short wavelength are fundamental: security, forensic, water/food sterilization, insulator marking/processing.

The UK economy has important players in all these fields. For example, Renishaw is world leader in the manufacture of metrology systems to be used for forensic and explosive detection, SPI lasers and Fianium are major manufacturers of optical fibre lasers for marking/processing, a number of companies provide UV water sterilization systems.

In the report "The worldwide Market for Lasers: Market Review and Forecast 2012" from Strategies Unlimited, in 2012 the global market for near-IR optical fibre lasers passed the $300m mark and the UK holds more than 10% of it, most of which in the companies spun off from the ORC. Applications are now limited mainly to metal processing. The possibility to extend the operational range outside the near-IR would allow for the processing of insulators as plastics and glasses and increase the fraction of laser marked ($7b) taken over by optical fibre lasers. Fianium (project partner) will investigate this possibility and provide the project with market specifications and investigate ways to exploit the results commercially.

In addition, the use of UV Raman for the remote detection of explosives and the measurement of traces of narcotics has been developed in the UK. Renishaw Ltd (project partner) firstly exploited commercially these systems and is currently the world leader of UV Raman spectrometers for applications ranging from forensic to security and gemmology. The use of fiberised sources will improve the signal to noise ratio in Raman systems by increasing the spectral density of exciting light allowing for fast measurements and clearer identification of single molecules.

Finally, UV sources are currently used in a range of sterilization and purification plants which range from swimming pools to drinking water plants to waste water treatment units. The Drinking Water Inspectorate reported that "to ensure microbiologically clean seawater it is a requirement in England and Wales for purification systems to be filled via the operational UV" and plans in the next 5 years to investigate the effect of UV radiation on the production of new chemicals in water.

The manufacture of UV light sources will have huge benefits an all these fields. It is predicted that the industrial connections of this project will facilitate the technology transfer from academia to the industry, with a demonstrator being planned at the end of this project.

On a long term (10-50 years) basis, it is reasonable to assume that the market for UV fibre sources will continue to increase and replace more conventional lasers, especially for application in the processing and marking of insulators like plastics and glasses. Similarly, as two of the largest manufacturers of optical fibre lasers are based in the UK, it is realistic to expect that the fraction of the world laser market taken over by British companies will increase.

Publications

10 25 50
 
Description 1) UV lasing has been demonstrated in Gd-doped silica glass; 2) a previously unknown photodarkening effect has been observed when using ns lasers to pump Gd-doped silica and silicate glasses; 3) UV light can be generated using very short (1cm) tapered optical fibres using cascaded nonlinear effects; 4) intrinsic surface ripples given by the nature of the material fabrication are a significant limit to the efficiency achievable with third harmonic generation; 5) four wave mixing can produce UV and has less limitations given by intrinsic surface ripples. 6) Gd-doped preforms exhibit strong fluorescence at 0.3um when pumped at the absorption lines of Gd3+ ion. 7) Gd doped silica fibres exhibit a strong fluorescence at ~0.31um; 8) Gd-doped phosphosilicate fibres also exhibit strong fluorescence at 0.31um when pumped at 0.25 or 0.27um.
Exploitation Route non-academic: the investigation og Gd-doped glasses resulted in three patents. one on devices capable to generate non-uniform phase beams, one on new magneto optical material and one on in-fibre mirrors. This last two patents have attracted significant interest for industrial applications in isolators and in distribute sensing.
Sectors Aerospace, Defence and Marine,Construction,Digital/Communication/Information Technologies (including Software),Education,Energy,Environment,Security and Diplomacy

 
Description ACTPHAST
Amount € 40,621 (EUR)
Funding ID P2014 - 63 
Organisation European Commission 
Department Seventh Framework Programme (FP7)
Sector Public
Country European Union (EU)
Start 10/2015 
End 03/2016
 
Description Giant magneto-optic response in rare-earth doped glasses and manufacturing of related devices and sensors
Amount £806,862 (GBP)
Funding ID EP/S013776/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 01/2019 
End 12/2021
 
Description Industry
Amount $69,607 (USD)
Funding ID HO2016050002A9 
Organisation Huawei Technologies 
Sector Private
Country China
Start 01/2017 
End 01/2018
 
Description Laser assisted manufacturing of taps for high power fibre laser
Amount £108,682 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 12/2018 
End 09/2019
 
Description Nanobaths for DNA analysis
Amount £140,896 (GBP)
Funding ID BB/M018962/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 09/2015 
End 04/2017
 
Description Seventh Framework Programme (FP7): P2015 - 36 - ACTPHAST
Amount € 63,722 (EUR)
Funding ID P2015 - 36 - ACTPHAST 
Organisation European Commission 
Department Seventh Framework Programme (FP7)
Sector Public
Country European Union (EU)
Start 09/2016 
End 09/2017
 
Description Zepler Institute
Amount £16,882 (GBP)
Organisation University of Southampton 
Sector Academic/University
Country United Kingdom
Start 01/2016 
End 07/2016
 
Description China Scholarship Council 
Organisation Guangdong University of Technology
Country China 
Sector Academic/University 
PI Contribution provided experimental set-up and software
Collaborator Contribution 12 months scholarship for ass. prof. Xiujuan Jiang
Impact 1 conference paper
Start Year 2014
 
Description Renishaw 
Organisation Renishaw PLC
Country United Kingdom 
Sector Private 
PI Contribution Access to equipment and to data originated from simulations. Experiments that resulted in the generation of UV light using four wave mixing.
Collaborator Contribution Expertise on second harmonic generation in all fibre systems. This source was used to generate UV using four wave mixing in optical fibre tapers.
Impact This collaboration produced three joint publications (DOI: 10.1364/OE.24.021777, 10.1364/OL.41.000761, 10.1117/12.2227585 ).
Start Year 2015
 
Description SPI Lasers 
Organisation SPI Lasers UK
Country United Kingdom 
Sector Private 
PI Contribution Use of SPI Lasers 150W 915nm pump towards the UV laser pumping set-up
Collaborator Contribution SPI lasers provided an array of 919nm diode lasers providing a total output of up to 150W.
Impact The main outcome of this collaboration is the enhanced set-up used to pump the UV laser.
Start Year 2016
 
Description Sol-gel Rare earth samples 
Organisation University of Milano-Bicocca
Department Department of Mathematics and its Applications
Country Italy 
Sector Academic/University 
PI Contribution pulled fibres out of samples provided by collaborators and used for the project. generated common IP
Collaborator Contribution provided several sol-gel samples, with sizes suitable for fibre drawing (1cm diameter, 7cm long) generated common IP
Impact 14 joint publications, 1 patent, 1 patent application
Start Year 2015
 
Title Fused Fibre Couplers, and Apparatuses and Methods for the Manufacture and Use thereof 
Description The application discloses a fused fibre coupler comprising a single mode fibre, SMF, and an orbital angular momentum fibre, OAMF, the fibres having a coupling portion in which the fibres are longitudinally aligned side by side and fused at least over a coupling length in which the SMF and OAMF are tapered such that the diameter of the SMF and the diameter of the OAMF give the fibres matching effective refractive indices for a single mode of the SMF and an orbital angular momentum, OAM, mode of the OAMF for a coupled wavelength of light. The coupler switches the input Gaussian like mode into a selected orbital angular momentum mode. 
IP Reference PCT/GB2016/051659 
Protection Patent application published
Year Protection Granted 2016
Licensed No
Impact none yet
 
Title MAGNETIC FIELD SENSORS, METHODS OF DETECTING A MAGNETIC FIELD, AND RELATED MAGNETICALLY RESPONSIVE LIGHT PROPAGATING COMPONENTS AND OPTICAL DEVICES 
Description The application relates to the technical field of magnetic field sensors. In particular, the application relates to magnetic field sensors incorporating magnetically responsive light propagating components formed to be usable as Faraday rotators, in particular in fibre form. The application also relates to other optical apparatus incorporating the magnetically responsive light propagating components. 
IP Reference GB1719576.9 
Protection Patent application published
Year Protection Granted 2017
Licensed No
Impact Filed in November 2017
 
Title OPTICAL FIBRE SENSING 
Description The present disclosure relates to apparatus and methods for sensing using an optical fibre. Aspects of the invention relate to a sensor system, a detection device, an optical fibre, a method of manufacture of an optical fibre and a sensing method. 
IP Reference GB1802708.6 
Protection Patent application published
Year Protection Granted 2018
Licensed No
Impact Patent application filed on 20 Feb 2018