Article
Chemistry, Physical
Inge Nys, Peter Ropac, Brecht Berteloot, Miha Ravnik, Kristiaan Neyts
Summary: Novel electro-optic components with enhanced functionality can be designed by using well-designed anchoring patterns in a liquid crystal (LC) device. Two types of nematic LC diffraction gratings with varying periodicity are presented, manufactured with patterned photoalignment at the confining substrates. The surface anchoring periodicity can redirect the incident light into different diffraction orders, resulting in a scattering appearance of the grating. The structural and optical properties of the gratings can be tuned by applying an external voltage.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Optics
Clemens Singer, Alexander Goetz, Adarsh S. Prasad, Martin Becker, Manfred Rothhardt, Sarah M. Skoff
Summary: This study demonstrates the thermal tuning capability of an alignment-free, fiber-integrated Fabry-Perot cavity, which can function as a narrowband filter with wavelength tuning and high suppression performance. Additionally, in the field of quantum optics, quantum emitters can be coupled to the cavity for reversible manipulation of cavity effects.
Review
Crystallography
Shiyuan Zhang, Wan Chen, Yang Yu, Qidong Wang, Quanquan Mu, Shixiao Li, Jin Chen
Summary: Recent research has shown that diverse twisting structures can be used to design liquid crystal polarization gratings and lenses with high diffraction efficiency, broad bandwidth, wide view, and large diffraction angle. By phase compensation, multi-layer twisting structures have been found to present a broader bandwidth and wider view angle, while Bragg twisting structures can achieve a large diffraction angle with high efficiency. Potential research directions on novel twisting structures were discussed based on theoretical analysis in the review.
Article
Engineering, Electrical & Electronic
Naikui Ren, Youlong Yu, Hongyang Li
Summary: An improved roughness measurement system using fiber Bragg gratings (FBGs) and machine learning was proposed in this study. Experimental results showed that extracted strain features of FBGs could be used individually for roughness measurement, and the polynomial regression algorithm performed better in roughness prediction and classification.
SENSORS AND ACTUATORS A-PHYSICAL
(2021)
Article
Optics
Hongye Li, Xin Tian, Hao Li, Baiyi Wu, Xiaofan Zhao, Meng Wang, Chenhui Gao, Binyu Rao, Xiaoming Xi, Zilun Chen, Zefeng Wang, Jinbao Chen
Summary: A pair of fiber Bragg gratings (FBGs) were fabricated using a visible femtosecond laser phase mask scanning technique on passive large-mode-area double-cladding fibers for multi-kilowatt fiber oscillators. The high-reflection (HR) and low-reflection (LR) FBGs have bandwidths of -1.6 nm and 0.3 nm, respectively. The all-fiber oscillator using these FBGs achieved a record output power of 5027 W with a slope efficiency of -82.1% and a beam quality factor M2 of -1.6 at maximum power. The thermal efficiency of the HR-FBG and the LR-FBG is 2.76 degrees C/kW and 1 degrees C/kW, respectively. This research provides an effective solution for robust high-power all-fiber laser oscillators.
CHINESE OPTICS LETTERS
(2023)
Article
Physics, Applied
Rowan Morris, J. Cliff Jones, Mamatha Nagaraj
Summary: This study investigates the use of surface acoustic waves to induce periodic vortices in a nematic liquid crystal device, resulting in adjustable grating periods. A linear relationship between the wavelength of the applied waves and the induced grating period is shown, allowing for the design of a novel device with continuously variable grating periods. These devices have the potential to overcome current technological limitations and create a new class of continuously variable diffractive optical elements.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Optics
Ben Pelleg, Carl Steinhauser, Marquise Pullen, Joseph Linden, Adam Fontecchio
Summary: This paper presents a mechanism for spectral line emission detection based on switchable spectral filters, enabling remote sensing tasks in a broad passband while detecting emission in a particular spectral line. The concept is demonstrated through modeling a sensor with an integrated HPDLC filter and building a detection algorithm capable of detecting spectral line emission.
Article
Optics
Yitao Wang, Matthieu Lancry, Maxime Cavillon, Bertrand Poumellec
Summary: This paper investigates the lifetime prediction of nanogratings written in silica glass using an infrared femtosecond laser. The accelerated aging experiments and monitoring of characteristic birefringence show that these nanostructures can survive for a considerable amount of time at high temperatures, with an estimated lifespan of over 10 years after a special treatment.
Article
Engineering, Electrical & Electronic
Yong Zhao, Yuechun Shi, Pan Dai, Shengping Liu, Lijun Hao, Yuxin Ma, Xiangfei Chen
Summary: This paper proposes, analyzes, and demonstrates a side-coupled Fabry-Perot resonator filter consisting of two dissimilar waveguides with pi phase-shifted Bragg grating. The resonance circuit is formed by mode conversion between the TE0 modes of the two waveguides, allowing for a wide free spectral range or a single strong resonance at the central wavelength of mode conversion. Compared to conventional F-P resonators, the proposed resonator can only couple one transverse mode to the bus waveguide, resulting in no intrinsic reflection and low resonance loss.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Optics
Leo Colliard, Guillaume Bilodeau, Tommy Boilard, Jerome Lapointe, Real Vallee, Martin Bernier, Matthieu Bellec
Summary: This paper proposes an innovative femtosecond laser writing approach that allows the fabrication of arbitrary long optical waveguides in coreless optical fibers directly through the coating. The experimental results demonstrate the few meters long waveguides operating in the near-infrared with low propagation losses. The refractive index distribution shows homogeneity with a quasi-circular cross section, and its contrast can be controlled by the writing velocity.
Article
Materials Science, Multidisciplinary
Jinho Lee, Yan Ososkov, Solenn Cozic, Aymeric Pastre, Remy Bernard, Stuart D. Jackson
Summary: We present a new design for active fluoride glass fibres that uses a metal coating instead of a polymer coating. A chemically fabricated 2-μm-thick silver layer is applied to the periphery of the fiber doped with Dy3+ ions, with coating lengths of up to 20 cm achieved. Using a sensitive fiber Mach-Zenhder interferometer (MZI) with a stabilized He-Ne laser, we accurately measure the temperature rise in the fiber core. Our results demonstrate that the metal coating can reduce the fiber core temperature by up to 22% for low power levels. This work lays the foundation for critical applications of active fluoride fibers where temperature reduction and stabilization are essential.
OPTICAL MATERIALS EXPRESS
(2023)
Article
Chemistry, Analytical
Siim Heinsalu, Katsuyuki Utaka
Summary: We present two methods to improve wavelength sensitivity for multi-slot sub-wavelength Bragg grating refractive index sensors, achieving significant improvements compared to previous results.
Article
Materials Science, Multidisciplinary
Svetislav Savovic, Ana Simovic, Branko Drljaca, Milan S. Kovacevic, Ljubica Kuzmanovic, Milos Ivanovic, Alexandar Djordjevich, Konstantions Aidinis, Daniele Tosi, Rui Min
Summary: This study proposes the investigation of bandwidth in multimode graded-index microstructured polymer optical fiber (GI mPOF) with a solid core using a modal diffusion approach. The bandwidth is reported for various launch radial offsets by numerically solving the time-dependent power flow equation and employing physics-informed neural networks. The results show that mode coupling enhances bandwidth at longer fiber lengths, and as fiber length increases, bandwidth approaches complete independence from radial offset, indicating the attainment of a steady-state distribution. Comparisons with traditional multimode GI POFs show that GI mPOF exhibits higher bandwidth performance and quicker improvement.
RESULTS IN PHYSICS
(2023)
Review
Crystallography
Tiegang Lin, Jin Xie, Yingjie Zhou, Yaqin Zhou, Yide Yuan, Fan Fan, Shuangchun Wen
Summary: This review paper discusses the physical principles, exposure methods, fabrication process, and promising applications of the liquid crystal circular polarization gratings, which have high diffraction efficiency and polarization selectivity characteristics.
Article
Crystallography
Yuan-Hang Wu, Sai-Bo Wu, Chao Liu, Qing-Gui Tan, Rui Yuan, Jing-Ge Wang, Ling-Ling Ma, Wei Hu
Summary: Researchers have achieved light-driven pitch tuning in hierarchical gratings formed in a molecular switch doped CLC, demonstrating a checkerboard hierarchical CLC grating and other patterns, which opens up new opportunities for intelligent functional materials and advanced photonic devices.
Article
Optics
Paul C. Gow, Q. Salman Ahmed, Paolo L. Mennea, Rex H. S. Bannerman, Alexander Jantzen, Christopher Holmes, James C. Gates, Corin B. E. Gawith, Peter G. R. Smith
Article
Engineering, Electrical & Electronic
Q. Salman Ahmed, Paul C. Gow, Christopher Holmes, Paolo L. Mennea, James W. Field, Rex H. S. Bannerman, Devin H. Smith, Corin B. E. Gawith, Peter G. R. Smith, James C. Gates
Summary: This paper presents the first demonstration of simultaneous UV written Bragg gratings and waveguides in germanium and boron-doped planar silica using a 5th harmonic solid-state nanosecond laser. The fabrication process of high-quality gratings and investigation of photosensitivity in the doped silica layer are discussed, along with the measurement of grating refractive index modulation, grating detuning bandwidth, and waveguide propagation loss. The study shows that pulsed UV lasers offer a promising alternative to conventional longer wavelength CW laser sources for direct grating writing in doped silica.
ELECTRONICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Mathias J. Weisen, James C. Gates, Corin B. E. Gawith, Peter G. R. Smith, Peter Horak
Summary: The study proposes the use of bi-directional propagation of light in silica integrated coupled waveguide structures for linear optical processing, implementing linear operations using symmetric and unitary matrices. It demonstrates the realization of an arbitrary 4x4 coupler through a linear sequence of more fundamental 2x2 couplers, and discusses the implementation in a silica integrated platform utilizing direct UV-written waveguides and grating couplers for optimized coupling efficiency.
IEEE PHOTONICS JOURNAL
(2021)
Article
Engineering, Electrical & Electronic
S. L. Jantzen, D. H. Smith, R. H. S. Bannerman, L. J. Boyd, J. C. Gates, P. G. R. Smith, C. Holmes
Summary: Two methods for inscribing co-located fibre Bragg gratings using small spot direct UV writing technique are described and a record number of gratings was reported. The study found that superimposed gratings and superstructured gratings were successfully inscribed with an interference spot of only 14 mu m in diameter.
ELECTRONICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Andrea Annunziato, Francesco Anelli, James Gates, Christopher Holmes, Francesco Prudenzano
Summary: Uniform Fiber Bragg Grating sensors based on Polarization-Maintaining fibers are designed for simultaneous longitudinal strain and temperature measurement of Carbon Fiber Reinforced Polymer laminates. Three different embedding methods for Panda, Bow tie and Pseudo-rectangle optical fiber shape sections are investigated. An exhaustive, accurate and robust investigation of the mechanisms originating Bragg wavelength shift is developed by considering a complete multiphysical model.
IEEE PHOTONICS JOURNAL
(2021)
Article
Materials Science, Multidisciplinary
P. C. Gow, Q. S. Ahmed, J. C. Gates, P. G. R. Smith, C. Holmes
Summary: The study reports rapid thermal consolidation of doped silica soot in a silicon carbide lined kiln subjected to microwave radiation, resulting in peak temperatures of >1350 degrees C after 18 minutes of irradiation. The glass underwent Newtonian cooling with an e(-1) of approximately 5 minutes. Optical characteristics of the planar glass layer were compared against traditional furnace consolidation approaches, showing potential for single-mode waveguides and Bragg gratings.
OPTICAL MATERIALS EXPRESS
(2021)
Article
Chemistry, Physical
Huanqing Ye, Jelena Gorbaciova, Chen Lyu, Claire Burgess, Alex S. Walton, Khadisha M. Zahra, Richard J. Curry, Rex H. S. Bannerman, James C. Gates, Peter B. Wyatt, William P. Gillin
Summary: The study demonstrates the critical role of vibrational modes in organic erbium materials in determining the efficiency of 1.5 μm Er3+ emission. By controlling the quenching effect, the pump power for population inversion can be significantly reduced at high erbium concentrations compared to conventional inorganic erbium materials.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Optics
Rex H. S. Bannerman, Devin H. Smith, Alan C. Gray, James C. Gates, Neil G. R. Broderick, Corin B. E. Gawith, Peter G. R. Smith
Summary: We demonstrate self-pulsing stimulated Brillouin scattering in a 250 mm long distributed feedback Raman fiber laser, achieving repetition rates up to 7 MHz, pulse widths of 25 ns, and peak powers of 1.2 W. The laser design can be constructed at various wavelengths as the Raman and Brillouin gain regions depend on the pump wavelength. Experimental results show that the outputs of pure Raman and Raman-pumped Brillouin lasing are highly correlated, indicating single-frequency behavior in continuous wave mode and near transform-limited pulsing in pulsed operation. A phenomenological model of the Raman-Brillouin interaction accurately predicts the pulsing behavior observed. Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License.
Article
Optics
Paul C. Gow, James C. Gates, Rex H. S. Bannerman, Joshua Nunn, Paolo L. Mennea, Peter G. R. Smiths
Summary: The Networked Quantum Information Technologies (NQIT) hub, as part of the flagship scheme in the United Kingdom, has successfully brought together academia, industry, and government to advance quantum photonics technologies. The interactive demonstrator developed by the Optical Engineering and Quantum Photonics Group at the University of Southampton's Optoelectronics Research Centre showcased a key device within NQIT and was exhibited at major science events.
OPTICAL ENGINEERING
(2022)
Article
Multidisciplinary Sciences
Peter A. Spring, Shuxiang Cao, Takahiro Tsunoda, Giulio Campanaro, Simone Fasciati, James Wills, Mustafa Bakr, Vivek Chidambaram, Boris Shteynas, Lewis Carpenter, Paul Gow, James Gates, Brian Vlastakis, Peter J. Leek
Summary: This paper reports high qubit coherence, low cross-talk, and single-qubit gate errors in a superconducting circuit architecture that can be tiled into a two-dimensional lattice of qubits. The architecture integrates an inductively shunted cavity enclosure with non-galvanic out-of-plane control wiring and qubits and resonators fabricated on opposing sides of a substrate. Experimental results demonstrate the feasibility of the design, and simulations predict that the enclosed qubits will maintain a clean electromagnetic environment at arbitrary scale.
Article
Optics
Dong-woo Ko, Q. Salman Ahmed, James W. Field, James C. Gates, Peter Horak
Summary: We investigated the performance of tilted Bragg gratings in planar waveguides fabricated by direct UV writing in photosensitive silica. Using an analytic expression, we designed gratings to generate output beams with specific shapes in free space and calculated their overall power coupling efficiency. Our simulations suggest that devices of millimeter length are most suitable for this technology given the currently achievable grating index contrasts.
Proceedings Paper
Engineering, Electrical & Electronic
S. T. Ilie, G. De Paoli, A. Flint, T. Dominguez Bucio, P. Ginel-Moreno, J. Sagar, A. Ortega-Monux, K. Lekkas, T. Rutirawut, L. Mastronardi, I Skandalos, I Molina-Fernandez, G. T. Kanellos, P. Cheben, P. G. R. Smith, J. C. Gates, F. Y. Gardes
Summary: Silicon nitride (SiNx) is a widely used material in CMOS photonics, enabling the development of low-cost CMOS compatible waveguides and photonic components. Researchers have successfully created a new type of surface-emitting silicon nitride waveguide with antenna lengths exceeding 5 mm. By utilizing small spot direct ultraviolet writing, they achieved periodic refractive index changes and obtained narrow beam widths.
SMART PHOTONIC AND OPTOELECTRONIC INTEGRATED CIRCUITS 2022
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Dong-Woo Ko, James C. Gates, Peter Horak
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC)
(2021)
