Chalcogenide glasses (ChGs), containing S, Se or Te as major constituent elements, stand out for nonlinear photonics materials in infrared band because of their wide transparency far into 20 µm and very high optical nonlinearities, two to three orders of magnitude greater than silica. However, ChGs faces a few serious issues; incompatibility with the complementary metal-oxide-semiconductor (CMOS) process; high scattering loss resulted from the sidewall roughness of a waveguide induced during patterning process; and free space coupling in/out at the chip end facets and resulting high coupling loss. In order to mitigate these drawbacks, we hybridized ChGs with CMOS compatible platforms, including silicon, silica, Ge-doped silica, and silicon nitride. In this talk I present the structural designs, fabrication procedures, and the experimental results of these hybridization schemes. I also discuss the pros and cons of each approach and conclude with my personal outlook on the schemes.

Associate Professor at the Australian National University and Part-time professor at Jinan University, Guangzhou
Qualifications: BSc (1992), M.Sc (1994), PhD (1998) in Materials Science and Engineering / Seoul National University
Employment:
2005. 1 – present, Laser Physics Centre / Australian National University
1998. 8 - 2004.12, Samsung Electronics
Research Interests:
- Chalcogenide photonic devices in near and mid Infrared
- Silicon photonics: Hydrogenated amorphous silicon, c-SOI
- Photonic nanostructures (metasurfaces)
- Nanostructured color filters
- Quantum Light-Matter Interface
Publications: Last five years ~60 SCI publications

The invention of optical glass fiber in the last century has revolutionized the ways people communicate, generate laser, and sense environment. However, the ever-increasing demands for higher data traffic, higher laser output power, and higher sensitivity to various physical quantities have pushed the performances of optical glass fiber close to its fundamental limits, which originate from the intrinsic properties of glass material itself, i.e., Rayleigh scattering, chromatic dispersion, nonlinearity, and radiation-induced damage. It becomes inevitable to search for disruptive fiber technology and concepts. Hollow-core fiber (HCF), which replaces the glass core with air or vacuum and thus has many unique characteristics, such as low nonlinearity, low dispersion, low latency, potentially low loss, and high radiation hardness, represents such a promising solution to tackle the above problems relevant to fiber materials. How to reduce the loss in HCFs, nowadays, becomes an intense research topic worldwide. In this talk, I will review our efforts in the past 5 years on ultralow loss anti-resonant HCF and its applications. Starting from a simplified model for the confinement loss of light guidance, I will show our state-of-the-art fiber design and fabrication, and preliminary applications in short-range data transmission. Our famed conjoined-tube HCF achieves a minimum loss of 2 dB/km at 1512 nm and a <16 dB/km bandwidth of 335 nm, opening the door for ultralow loss anti-resonant HCF. It also shines new light on conquering the Rayleigh scattering loss limit of silica glass fiber and realizing low-latency fiber communications insensitive to practical environment variations.

Wei Ding received his PhD degree from Bath University (UK) in 2007, and did postdoc in France and UK before joining Institute of Physics, Chinese Academy of Science (Beijing) in 2011. Now, he is a professor in Institute of Photonics Technology, Jinan University (Guangzhou). He has published more than 40 papers in international journals with H-index of 15 (Web-of-Knowledge). His research interests include micro-structured optical fiber, integrated photonics, optical fiber communications, nonlinear optics, and nanophotonics.

Optical glass and fiber working in near/mid-infrared (NIR/MIR) region are extensively investigated owing to their various potential applications. Quantum dot (QD, such as PbS) doped glass with tunable broadband NIR emission and rare-earth-ion (such as Er3+) doped glass ceramics with enhanced NIR/MIR emission are well suitable for the above-mentioned applications. Importantly, the QD/nanocrystal-doped glass fibers are fabricated by the modified fiber-drawing method, which provides an ingenious way to break through the bottleneck problem of uncontrollable rapid growth of nanocrystals existing in traditional fiber-drawing method. Furthermore, thermal and optical properties between fiber core and cladding glass are well matched, which ensure that the structure of the precursor fiber is well preserved during the fiber-drawing process. The excellent spectroscopic characteristics and well-preserved structure indicate that the obtained QD/nanocrystal-doped glass fiber may be a promising gain fiber material. The experimental results also confirm that enhanced single mode laser output are realized in nanocrystal-doped glass fiber.

Guoping Dong received his PhD degree from Shanghai Institute of Optics and Fine Mechanics, CAS in 2010, where he received the “Chinese Academy of Sciences President Award” in 2010. Since then, he worked in South China University of Technology as a research assistant (2010), associate professor (2011) and full professor (2014). And he has been leading his own research group about the optical functional glass, optical fiber and devices. He has coauthored about 150 peer-reviewed papers with around 4000 citations. He is the author of 1 book chapters and >20 authorized patents. He has been Session Chair/Organizing Committee Member for more than 20 conferences. He was also invited to give ~30 Invited Talks in various conferences, including International Congress on Glass (ICG), ISNOG, GOMD, LTO, IUMRS-ICEM, etc. He has received “Guangdong Natural Science Award (second-class)”, “Guangdong Natural Science Foundation for Distinguished Young Scholars”, etc. His current research interests are focused on the design, fabrication and photoelectronic properties of novel photonic material and devices.

Due to the massive increase in users and required data capacity in optical communication networks, the demand for transmission of ultra-high definition video and cloud computing are driving the need for higher capacities in signal transmission and signal processing. Alongside the challenge of bandwidth, another serious concern is energy consumption and resulting CO2 emissions. The Internet is already today responsible for about 9% of the global electricity consumption and this energy demand is still rising. It is of utmost importance to reduce the energy per bit with 20-30% traffic growth rates. It is also becoming increasingly important to utilize the installed network resources flexibly to support more intelligent applications e.g. Internet of Things (IoT), Industry4.0 and autonomous cars.
In this paper, we provide an overview of recent progress on advanced optical signal processing using time lens based optical Fourier transformation. The time lens based optical Fourier transformation is an extremely attractive tool for many different applications. We will outline time lens based all-optical processing of spectrally-efficient signals, scalable WDM regeneration and our most recent activities on optical access networks.

Dr. Pengyu Guan received his Ph.D. degree in communications engineering from Tohoku University, Sendai, Japan, in 2012. For his achievements during the Ph.D, he received the Student award “Best paper Prize” from IEEE Sendai Section in 2009, the Chinese Government Award for Outstanding Self-financed Students Abroad in 2011, and the Tohoku University President’s Award in 2012, which is the highest honor at Ph.D. graduation. Currently he is a researcher in the High- Speed Optical Communications Group, DTU Fotonik, where he is involved in research on high-speed optical signal processing and optical communication systems. Dr. Guan has been innovative and led to a number of impressive world- first achievements at record high bit rate and channel counts. He has authored or co-authored more than 72 peer reviewed publications, including 6 postdeadline papers, 3 top-scored papers, 10 invited papers in top IEEE/OSA journals and world-renowned conferences. He hold 4 patents as the first inventor and have won 4 prizes (1 within the group), as well as 4 highly competitive grants including a very prestigious VILLUM Young Investigator grant.

A LD-pumped 6 kW Yb-doped single mode fiber laser at 1080 nm has been demonstrated, which represents the highest level of single mode fiber laser in this scheme. Different from the traditional tandem pumping, the fiber laser is directly pumped by 976 nm laser diodes for higher wall-plug efficiency and more compact structure. In this paper, we discuss some methods which are adopted for high stimulated Raman scattering (SRS) suppression in the MOPA system. Numerical simulation is conducted to optimize parameters of the components to balance the requirements of the high power, pump slope efficiency and SRS suppression. Experimentally, based on all fiber construction 6 kW output power with M2<2 and Raman suppression ration better than -20 dB is obtained. This laser can be widely used in industrial processing, scientific research and other applications with strict demands on beam quality and power level.

Shaofeng Guo received his Ph.D. degree in Optical Engineering from National University of Defense Technology (NUDT) in 2003, and did post-doctor in Chinese Academy of Science from 2004 to 2006. He visited CREOL in University of Central Florida from 2009 to 2010 then worked in NUDT until 2016 as a professor. Now, he is the CEO of Hunan DK laser company. He has published more than 30 papers in international journals and has more than ten patents. His research interests include high power fiber lasers, fiber components and nonlinear optics.

Multi-materials, multi-functional fibers integrate different materials (like metal, semiconductor, insulator, etc.) to perform various functionalities within one fiber. Such fibers would find lots of interesting applications in security, energy, and bio-related areas. Centering to these multi-materials fibers is a fiber fabrication method called “co-draw” in which a macro-scale preform is firstly designed and fabricated, and then heated and get elongated into meters-long fiber. During the thermal drawing process, all the fiber materials get softened and shrunk to a much smaller scale proportionally. In this process one of the fiber materials' thermal property, i.e. viscosity, plays an important role, as people need to manage it to prevent the complex structure inside the fiber distorted. Study and utilize this thermal property, or work around this thermal limit is of interest both in science and in engineering. Here we demonstrate a few works that explore different possibilities around the viscosity to achieve new materials and new structures inside the fiber. These works (1) uses the viscosity contrast to induce the selective thermal breakup for a ladder-like structure in the fiber, or (2) control the viscosity to get fibers with a surface structure feature down to nanometer scale, or (3) design a chemical reaction to synthesize materials during the fiber production process to overcome the limit of the viscosity restriction. Benefitting from the new materials and the new structures inside the fiber which otherwise will not be normally possible, a fiber device with better performance or more functionalities is thus realized.

Dr. Chong Hou is a professor in School of Optical and Electrionic Information (SOEI) in Huazhong University of Science and Technology (HUST). His main research interests include multi-material multi-functional fibers and their applications on energy, sensing, healthcare, and environment. He obtained his B.S. (2009) and Ph.D (2016) degree from Peking University and MIT, respectively. He is the recipient of the 1000 Young Award in 2019.

Photonic crystal fibres (PCFs) made from soft glasses (e.g., heavy-metal oxide, fluoride or chalcogenide) and polymers have attracted much attention because of novel optical properties and functionalities which are not observed in silica-based fibers [1]. Drawing soft-glass, or soft-glass/polymer hybrid fibres is however, very challenging due to a much faster change in viscosity with temperature, which means that the drawing temperature must be controlled within a narrow range (less than ±25°C), as well as compatible pairs (thermal, optical and structural properties) for drawing soft-glasses and polymers together. Over the last few years, with the recent emergence of 3D printing, we have been developing novel fabrication techniques through glass extrusion and etching, so as to be able to draw PCFs with nanoscale features that are deemed very difficult if not impossible to realise by “stack-and-draw”. These novel PCFs are used for various applications such as opto-mechanical interactions, photochemistry, quantum optics and nonlinear dynamics. In the talk, we will first present work on our recent achievements on fibre fabrication. After that I will report new procedures making use of 3D printing, as well as techniques for drawing chiral twisted fibres. Finally, we will discuss various applications of the fabricated fibres.

After obtaining his PhD degrees at the University of Leeds (UK) in 2009, Dr. Jiang joined the group of Prof. Philip Russell’s division at the Max-Planck-Institute for the Science of Light (MPL), as the head of the TDSU3: fiber fabrication and glass studio. He studied the ring-cavity fiber laser, mode-locked by saturable absorption based on single-wall carbon nanotubes and infrared optical fibers for chemical sensing during his MSc and PhD. At MPL, he is mainly working on the fabrication of photonic crystal fiber (PCF), made from various glasses (silica and soft glasses), and also on several projects such as supercontinuum generation, photochemistry in hollow core fibers and 3D particle trapping using high NA fibers. Dr. Jiang has a strong publication record in journals such as Nature Photonics, Optica, Progress in Materials Science, Optics Letters, Journal of Lightwave Technology, Optics Express, Inorganic Chemistry, Sensors and Actuators B etc, and serves as reviewers for many journals such as Nature Communications, Optica, Light: Science and Applications, Optics Letters, etc.

Micro- and nano-structured optical fibers enable enhanced non-linear light matter interaction over a long distance. This talk presents recent developments in the use of hollow-core optical fibers and sub-wavelength nanofibers for stimulated Raman spectroscopy with enhanced performance. With stimulated Raman gain and dispersion spectroscopy, we have demonstrated hydrogen sensors with hollow-core and tapered nanoscale optical fibers and achieved ppm (parts per million) level detection resolution and dynamic range of five orders of magnitude. Distributed detection of hydrogen over 100 meters of hollow-core fiber is also demonstrated with response time of less than 1 min and dynamic range of over three orders of magnitude.
We also report the first demonstration of group delay tuning with stimulated Raman scattering induced dispersion in a hydrogen-filled hollow-core optical fiber. Tunable pulse delay is realized by changing pump power as well as hydrogen pressure. With ~80-m-long hollow-core fiber filled with hydrogen, we achieved continuously tuning of pulse delay up to 1.4 ns by varying the Raman gain from 0-10 dB. This work could be useful for slow light applications such as buffering in data communication systems.

Wei Jin received a BEng degree from Beijing University of Aeronautics and Astronautics in 1984 and a Ph.D degree from University of Strathclyde in 1991. He joined Hong Kong PolyU as an assistant Professor in 1996 and is currently the Chair Professor of Photonic Instrumentation. He researched on various fiber components and sensor systems, and is currently working on micro-structured photonic devices and sensors. He edited two books, delivered >70 invited/keynote/plenary talks, author/co- authored >260 journal papers and 15 patents. He received PolyU President’s Award for Outstanding Performance, PolyU’s Outstanding Professional Services and Innovation Award, Chiang-Jiang Chair Professor Award, Distinguished Young Scholar Award (Category-B) as well as six best conference/student paper awards. He is a fellow of OSA.

Multimode fibers together with multimode VCSELs are currently used in data centers for short distance optical communications due to its cost effectiveness and power efficiency. As capacity demands rise and the overall throughput through the fiber increases, effects that were not taken into consideration in the past need to be evaluated and its effect understood more carefully. The interaction of chromatic dispersion in single mode fiber and the linewidth enhancement factor has been studied in the past and found relevant for several transmission systems. This effect is studied here numerically, and its impact analyzed for multimode fiber links with relevant systems lengths as found in data center applications. For this purpose, a state of the art multimode VCSEL model was enhanced and matched to a series of measurements performed on a 25G VCSEL and its interaction with multimode fiber studied using PAM4 modulation format. Results show that the interaction of the linewidth enhancement factor of multimode VCSELs with the chromatic dispersion in multimode fibers can have a significant impact on the transmission performance even at short distances. This has also led to the development of a measurement technique which enables the measurement of the linewidth enhancement of the multimode VCSEL for each transverse mode. First results seem to indicate that the linewidth enhancement factor only varies slight between different transverse modes of the multimode VCSEL.

Dr. -Ing. A. Juarez received his Dipl. -Ing. degree in electrical engineering in 2009 and his PhD in fiber optics communications in 2015 from the Technical University of Berlin (TUB). He then joined Corning Optical Communications in Berlin where he worked until 2018 in topics related to active optical cables and optical short links for data center applications. Since September 2018 he has joined the modeling group in Corning Research & Development Corporation in Corning, NY, USA where he has been investigating multimode VCSELs and their interaction with multimode fiber.

Fiber lasers are now associated with high average powers and high beam qualities. Both these characteristics, which required by many industrial, defense and scientific applications, are mainly founded on the large-mode-area single-mode gain fiber. In this report, we have reviewed the fabrication and performance of the Yb3+-doped large-mode-area single-mode fiber. We will focus on the PD and the MI that limit the power stability and beam quality of the high power fiber laser. It is suggested that the core composition, structure design and fiber fabrication are the fundamental ways to improve the performance of Yb3+ doped fiber. With the deep research on photo-bleaching, it is now an available solution to mitigate PD. Additionally, we introduce recent advance in ultra-wideband fiber amplification and fiber laser based on mesoporous silica glass in detail.

Jinyan Li obtained PhD from Shanghai institute of optics and fine mechanics, Chinese Academy of Sciences (CAS) in 2001. He joined in the Wuhan National Laboratory for Optoelectronics since 2008 and promoted as full professor in 2008. He is currently an deputy director of the Laser and THz Performance Laboratory of the Wuhan National Laboratory for Optoelectronics. During the long career on special fiber preparation and its amplification and laser field, he has published more than 100 peer review papers in ACS photonics, nanoscale, Optics express, Optics Letter etc. more than 70 invited talks in domestic and international conferences. As the first contributor, he won 2 provincial second award on technology invention and 1 ministry first awards on science and technology.

Fiber optics are small structure that is easy to deploy and install, and has a profound impact in the many field, e.g. telecommunication, laser and sensing. However, considering a wide range of applications, complex structures and more functions will be an important research direction; at the same time, optical devices that tend to be miniaturized in size. This report introduces the design, development, and strength testing of ultra-fine-diameter polarization-maintaining fibers, focusing on bending loss and strength reliability. The second part is based on the developed ultra-fine diameter fiber, a fiber ring was winded as small as 40mm diameter, then assembled to a small size fiber optic gyroscope. An opto-electronic sensing capability was demonstrated that combines multi-functions into a two-wheel balance car, include the functions like self-balancing and single line LiDar.

Zhenggang Lian, obtained bachelor's degree and Ph.D. degree in Electronic Engineering from the University of Nottingham, in 2006 and 2010 respectively. He then worked in the Optoelectronics Research Centre at the University of Southampton; generated more than 40 articles. From the year of 2014, he has been working in Wuhan Yangtze Optical and Electronics Co.; and oversee the R&D department. In 2016, he joint Huazhong University of Science and Technology as part-time professor. He is associate editor of Optical and Quantum Electronics and the director of Wuhan Optics Valley Metrology Centre. He led a team to develop new specialty optical fibers and responsible for 10 national research projects. His research interests include design / optimizing specialty optical fibers; the main target application are fiber sensing, fiber laser, and IR transmission. He has achieved a total output value nearly 100 million RMB per year, in industry.

Fiber lasers have a wide range of applications for their excellent performances. We have fabricated a novel Yb:YAG-derived silica fiber (YDSF) using a Yb:YAG crystal as the core material and a high-purity silica tube as the cladding material. Using this approach, the fiber combines some characteristics of YAG crystals and silica glass fibers. It possesses characteristics including high rare-earth doping potential, high thermal conductivity, high SBS threshold, and low photodarkening effect. These properties indicate that this kind of fibers have the potential to realize high-power lasers and single-frequency lasers. The fiber was fabricated with a molten-core method. The gain coefficient and transmission loss at 1.06 μm were measured to be 1.7 dB/cm and 0.018 dB/cm, respectively. Using the YDSF, an all-fiber-integrated cladding-pumped laser was demonstrated. With an incident pump power of 28 W, an output power of 6 W was obtained at 1.06 μm. This is the highest power achieved in similar YDSF lasers. The corresponding slope efficiency was 21.7%. In addition, with the distributed Bragg reflection structure, we obtained a single-frequency output with a maximum output power of 110 mW with a slope efficiency of 18.5%. The linewidth was 93 kHz.

Zhaojun Liu, Doctor of Engineering, Professor, Doctoral Supervisor, School of Information Science and Engineering, Shandong University, Distinguished Young Scholar of Shandong University, Postdoctoral Fellow, Lehigh University, USA. Associate Dean of School of Information Science and Engineering, Shandong University, Deputy Director of Key Laboratory of Laser and Infrared System Integration Technology of the Ministry of Education. He is a review expert for projects such as the National Natural Science Foundation and reviewer of publications such as Opt. Lett., Opt. Express, IEEE Photonics Techno. Lett. The main research directions include fiber material preparation technology, distributed fiber optic sensing technology, single-frequency laser technology, etc.

Due to the overwhelming advantages compared with traditional electronic sensors, fiber-optic acoustic sensors have arisen enormous interest in multiple disciplines. In this paper, we present the recent research achievements of our group on weak acoustic signal detection technology. The main point of our research is diaphragm based Fabry-Perot acoustic sensors, including gold, aluminium, titanium, graphene and micro-electromechanical systems (MEMS) based silicon nitride diaphragm. These acoustic sensors show high sensitivity and wide detection frequency band. In addition, high precision acoustic signal interrogation technology and sensitivity enhancement technology are also proposed. Moreover, our attention has also been paid on lock-in amplifying technology to extract weak acoustic signal efficiently.

Ping lu , Professor ,Ph.D.She graduated from huazhong university of science and technology to obtain a Ph.D in Electronic science and technology, who was promoted to associate professor and professor in 2006 and 2011 respectively , and was engaged in postdoctoral research work in Optical Sciencs Center of University ofArizona during 2009-2010 .Her mainly research work include Fiber sensor, Fiber laser,Fiber optics. She has published more than 50 well-known international journal papers and apply for more than 20 national invention patents.

Seismic geophones are widely used to get stratum information in petroleum geophysical exploration. As one of the most advanced sound field detection technology, optical fiber distributed acoustic sensor (DAS) have many superiorities, such as easy deployment, high cost performance ratio, wide range measurement and so on. In this Presentation, DAS technology that using interferometric demodulation is introduced. Principal, demodulation algorithm, and parameter test are researched in detail. Furthermore, a ground geophysical prospecting test is implemented and a very clearly seismic section image is drawn out. Performance and test data of the DAS are discussed in detail. Convenient, large data and big coverage make it potentially better suited for geophysical prospecting applications.

Jiasheng Ni is associate Professor, director of special fiber research center at the Laser Institute of Shandong Academy of Sciences, of laser Institute of Shandong Academy of Science. From 2014 to 2015, he was a senior visiting scholar at the UNSW, Australia. His current research interests include optical fiber laser and optical fiber sensors.

Gas-filled hollow-core photonic crystal fibres (HC-PCFs) provide a convenient platform for studies of nonlinear dynamics as well as for applications such as ultrashort pulse compression to a single-cycle duration and efficient generation of broadband radiation, which can be tuned across the deep and vacuum ultraviolet (UV) spectral region. As these nonlinear processes rely on the weak and spectrally flat dispersion of HC-PCFs, spectral anti-crossings between the fundamental core mode and core-wall resonances influence them by altering the dispersion. Here I discuss the effects of anti-crossings on the nonlinear propagation of ultrashort laser pulses in gas-filled HC-PCFs. The spectrally localised modification of the real part of the modal refractive index introduces new phase matching routes for nonlinear parametric process. Moreover, I show that anti-crossings lying close to the pump wavelength are detrimental for soliton self-compression and UV generation and demonstrate how to mitigate these effects by tailoring the core-wall thickness. Finally, I discuss how to further manipulate the properties of HC-PCFs via tapering them and show that fibres with remarkably small core diameters (<6 µm) and capillary core-wall thickness (<90 nm) can be obtained by post-processing.

Francesco Tani leads the ultrafast nonlinear optics sub-group in Philip Russell’s division at the Max Planck Institute for the science of light. In 2010 he received his master degree in theoretical physics from the university of Rome La Sapienza with a thesis on laser-plasma acceleration. In 2014 he received a PhD in physics from the Max Planck Institute, where he investigated the nonlinear dynamics of ultrashort pulses propagating in gas-filled photonic crystal fibre and exploited these to develop novel light sources. In 2016 after two years as a postdoctoral research fellow in the same institute, he became team leader of the ultrafast nonlinear optics sub-group.

Optical diffraction elements (ODEs) are key components for innovative applications based on spectral encoding. Two most recent examples are wavelength-controlled laser beam steering for optical wireless communication and wavelength-to-space mapping for photonic time stretch imaging. Most commonly used ODEs are free-space ruled or holographic diffraction gratings, which however suffer from some inherent drawbacks, such as bulky construction, limited diffraction efficiency (up to 75%) due to the inherent zeroth-order reflection, and high coupling loss between free-space diffraction gratings and optical fibres in the system. In this work, we report the use of a 45° tilted fiber grating (TFG) as a highly efficient, low cost and compact in-fiber diffraction grating device. Compared to conventional free-space diffractive devices, the in-fibre diffraction device provides significant advantages of high diffraction efficiency (>99%), compactness, low cost and inherent fiber-compatibility, and holds great promise in fibre and free-space interaction. Its superior performance in beam-steered optical wireless transmission and ultrafast photonic time-stretch imaging is presented with experimental demonstrations.

Chao Wang received his BEng degree from Tianjin University in 2002, MSc degree in Optics from Nankai University in 2005, and Ph.D degree in Electrical and Computing Engineering from University of Ottawa in 2010. From 2011 to 2012, he was a NSERC Postdoctoral Fellow at the University of California, Los Angeles (UCLA). He is currently a Senior Lecturer (Associate Professor) in the School of Engineering and Digital Arts at the University of Kent, UK, where he first joined as a Lecturer in 2013. His research interests lie in microwave photonics, ultrafast optical imaging, optical communications, and optical sensing. His research activities have been well funded by EU Marie-Curie Actions, the Royal Society, and the Engineering and Physical Sciences Research Council (EPSRC) and Catapult of UK. He was the recipient of Graduate Fellowships from both IEEE Photonics Society (2009) and IEEE MTT Society (2010), Chinese Government Award for Outstanding Self-Financed Students Abroad (2009), NSERC Postdoctoral Fellowship (2011) and EU Marie Curie CIG Award (2014).

Gas stimulated Raman scattering (SRS) has been demonstrated to be an effective method to obtain high-power narrow-linewidth lasers of otherwise unobtainable wavelengths, especially in the ultra-violet and mid-infrared spectral range. In traditional gas cells the effective interaction length is very short and the system can be bulky and cumbersome, limiting the applications of these lasers. The advent of anti-resonance hollow-core fibers and their properties of long effective interaction length, high optical confinement, and the possibility of control of the effective gain spectrum make it possible to develop a novel type of laser, named fiber gas Raman lasers, which combines the advantages of both fiber and gas lasers. By properly designing the transmission bands of hollow-core fibers, selecting active gases and pump sources, fiber gas Raman lasers can potentially provide a wide range of emission wavelengths from the UV to the IR pumped with commercial 1μm lasers. Owing to the nature of transitions in atomic and molecular gases, fiber gas Raman lasers are spectrally narrow even without additional linewidth limiting measures. We have demonstrated efficient high-power, narrow-linewidth 1.5 μm, 2 μm and 3 μm fiber gas Raman lasers using hollow-core fibers filled with different gases from 1064 nm solid-state lasers. Our work provides a very possible way to obtain high-power, narrow-linewidth mid-infrared fiber lasers by gas stimulated Raman scattering in hollow-core fiber pumped with normal 1μm lasers.

Zefeng Wang, Professor, Ph.D. supervisor, College of Advanced Interdisciplinary Studies, National University of Defense Technology (NUDT). He received Doctor degree in Optical Engineering from the NUDT in June 2008, and visited Bath University in UK from October 2012 to July 2014. He has published more than 100 journal papers. His research interests cover mainly fiber lasers, gas lasers by hollow-core fibers, fiber gratings fabrications and applications.

The interference fading, which is detrimental for signal retrieval in phase-sensitive optical time-domain reflectometry (Φ-OTDR). In this talk, we will theoretically describe and experimentally verify how the fading phenomenon in fiber will be suppressed with an arbitrary number of independent probing channels. Furthermore, fading phenomenon is analyzed in frequency domain, and a novel spectrum extraction and remix method is proposed to achieve fading-free operation for Φ-OTDR with heterodyne detection, utilizing single rectangular probe pulse and makes full use of its spectral contents. The operation principle is theoretically analyzed, and it is well confirmed by both simulation and experimental results.

Zinan Wang received the PhD degree from Beijing University of Posts and Telecommunications, China, in 2009 (During 2007-2009, he was with Alcatel-Lucent Bell Labs as a visiting student). He was with Cornell University, as a postdoctoral research associate during 2009-2010. He joined University of Electronic Science and Technology of China in 2010, and became a full professor since 2015. His research interests include distributed fiber sensing and nonlinear fiber optics. He has published more than 130 papers in international journals and conference proceedings, and he is holding 16 Chinese patents and 2 US patents. He has given more than 18 invited talks at academic conferences, and served as TPC member for a number of conferences. His research was highlighted in ‘Optics in 2014’ by OSA Optics and Photonics News. He is a recipient of IOP Publishing Top Cited Author Award (China) in 2018. Zinan Wang is an Associate Editor for both IEEE Photonics Technology Letters and IEEE Access, and he is an IEEE & OSA Senior Member.

Optoelectronic and electronic systems that can offer performances of planar, rigid wafer-based devices but with the attributes of flexible, bendable, soft, stretchable and wearable are opening a breadth of unique applications. In particular, the recent development of thermal drawing – the same process used to fabricate optical fibers – of different materials with disparate properties into one-dimensional fibers paves a novel way towards advanced optoelectronic and electronic functionalities over unconventional substrates. In this presentation, I will show this approach provides a compelling platform for the production of unconventional optoelectronics and electronics as well as fundamental research in materials science and physics. I will first show how we can fabricate an electrically addressed polycrystalline semiconductor domain with ultra-large grains, controllable crystallization depth as well as preferentially crystallographic orientations in optoelectronic fibers by controlling the nucleation and growth of the semiconductor. These fibers exhibit high performance that is comparable to that of commercial Si devices. By engineering interfacial energy of crystal planes of semiconducting materials in solution, I will then show that we are able to fabricate single-crystal nanowire-based optoelectronic fibers. The resulting nanowire-based fiber devices exhibit an unprecedented combination of excellent optical and optoelectronic properties in terms of light absorption, responsivity, sensitivity and response speed that compare favorably with other reported nanoscale wafer-based devices. We have demonstrated the unique capability of these functional fibers for fluorescent imaging based on a single fiber exhibiting simultaneous efficient optical guidance and excellent photodetecting performance.

Wei Yan obtained his M.S. degree from Shenyang National Laboratory for Materials Science at the Institute of Metal Research, Chinese Academy of Science in 2013 and Ph.D. degree from the department of Materials Science and Engineering at the Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland, 2017. Currently, he is a postdoctoral fellow at the Research Laboratory of Electronic at the Massachusetts Institute of Technology (MIT), USA. His research interests focus on fiber-shaped flexible and stretchable electronics and optoelectronics for applications in sensing, energy harvesting, robotics, smart textiles, artificial intelligence, healthcare and neuroscience as well as the fundamental study of in-fiber functional materials.

We exploit stimulated Brillouin scattering in gases to achieve unprecedented nonlinear optical amplification. The gain coefficient is 10 times larger than any reported nonlinear gain in gas-filled hollow-core photonic crystal fiber and 6 times larger than the strongest nonlinear gain in standard silica single-mode fiber (SMF). This massive gain enables us to achieve high performance distributed temperature sensing and low threshold Brillouin lasing. For sensing, ~1 cm spatial resolution and 0.3 oC temperature resolution is demonstrated, fully free of strain cross sensitivity, a major impairment in all Brillouin-based sensing systems. Substantially higher performance is obtained by virtue of the higher Brillouin gain, narrower gain linewidth and relaxed optical power restrictions when compared to solid silica SMF. A gas Brillouin laser with 140 mW threshold power is also realized. These systems can be designed to operate at any wavelength from vacuum ultraviolet to mid-infrared thanks to the nature of stimulated Brillouin scattering. These open new avenues in gas-based nonlinear optics and distributed fiber sensing, with possibilities of large amplification, new light sources as well as sophisticated all-optical signal processing in hollow-core fibers.

Fan Yang received his B.Sc. and M. Sc. Degrees from Huazhong University of Science and Technology, and the PhD degree in Electrical Engineering from The Hong Kong Polytechnic University. He is now a postdoctoral researcher in the Group for Fibre Optics (GFO) at École Polytechnique Fédérale de Lausanne (EPFL). His research to date has resulted in more than 20 peer-reviewed journal publications in the fields of gas-based nonlinear optics, laser spectroscopy, photonic crystal fiber and distributed fiber sensing.