Imperial College London

Dr Robert Woodward

Faculty of Natural SciencesDepartment of Physics

Academic Visitor
 
 
 
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Contact

 

+44 (0)20 7594 7639r.woodward12 Website

 
 
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Location

 

221EBlackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

55 results found

Paraiso TK, Woodward R, Marangon DG, Lovic V, Yuan Z, Shields AJet al., 2021, Advanced Laser Technology for Quantum Communications (Tutorial Review), ADVANCED QUANTUM TECHNOLOGIES, Vol: 4

Journal article

Pittaluga M, Minder M, Lucamarini M, Sanzaro M, Woodward RI, Li MJ, Yuan Z, Shields AJet al., 2021, 600-km repeater-like quantum communications with dual-band stabilization, Nature Photonics, Vol: 15, Pages: 530-535, ISSN: 1749-4885

Twin-field (TF) quantum key distribution (QKD) fundamentally alters the rate-distance relationship of QKD, offering the scaling of a single-node quantum repeater. Although recent experiments have demonstrated the new opportunities for secure long-distance communications allowed by TF-QKD, formidable challenges remain to unlock its true potential. Previous demonstrations have required intense stabilization signals at the same wavelength as the quantum signals, thereby unavoidably generating Rayleigh scattering noise that limits the distance and bit rate. Here, we introduce a dual-band stabilization scheme that overcomes past limitations and can be adapted to other phase-sensitive single-photon applications. Using two different optical wavelengths multiplexed together for channel stabilization and protocol encoding, we develop a setup that provides repeater-like key rates over communication distances of 555 km and 605 km in the finite-size and asymptotic regimes respectively and increases the secure key rate at long distance by two orders of magnitude to values of practical relevance.

Journal article

De Marco I, Woodward RI, Roberts GL, Paraiso TK, Roger T, Sanzaro M, Lucamarini M, Yuan Z, Shields AJet al., 2021, Real-Time operation of a multi-rate, multi-protocol quantum key distribution transmitter, Optica, Vol: 8, Pages: 911-915, ISSN: 2334-2536

Quantum key distribution (QKD) is the best candidate for securing communications against attackers, who may in the future exploit quantum-enhanced computational powers to break classical encryption. As such, new challenges are arising from our need for large-scale deployment of QKD systems. In a realistic scenario, transmitting and receiving devices from different vendors should be able to communicate with each other without the need for matching hardware. Therefore, practical deployment of QKD would require hardware capable of adapting to different protocols and clock rates. Here, we address this challenge by presenting a multi-rate, multi-protocol QKD transmitter linked to a correspondingly adaptable QKD receiver. The flexibility of the transmitter, achieved by optical injection locking, allows us to connect it with two receivers with inherently different clock rates. Furthermore, we demonstrate the multi-protocol operation of our transmitter, communicating with receiving parties employing different decoding circuits. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.

Journal article

Woodward RI, Lo YS, Pittaluga M, Minder M, Paraiso TK, Lucamarini M, Yuan ZL, Shields AJet al., 2021, Gigahertz measurement-device-independent quantum key distribution using directly modulated lasers, NPJ QUANTUM INFORMATION, Vol: 7

Journal article

Hu G, Yang L, Yang Z, Wang Y, Jin X, Dai J, Wu Q, Liu S, Zhu X, Wang X, Wu T-C, Howe RCT, Albrow-Owen T, Ng LWT, Yang Q, Occhipinti LG, Woodward R, Kelleher EJR, Sun Z, Huang X, Zhang M, Bain CD, Hasan Tet al., 2020, A general ink formulation of 2D crystals for wafer-scale inkjet printing, SCIENCE ADVANCES, Vol: 6, ISSN: 2375-2548

Journal article

Majewski MR, Woodward RI, Jackson SD, 2020, Dysprosium Mid-Infrared Lasers: Current Status and Future Prospects, LASER & PHOTONICS REVIEWS, Vol: 14, ISSN: 1863-8880

Journal article

Henderson-Sapir O, Bawden N, Majewski MR, Woodward RI, Ottaway DJ, Jackson ADet al., 2020, Mode-locked and tunable fiber laser at the 3.5 μm band using frequency-shifted feedback, Optics Letters, Vol: 45, Pages: 224-227, ISSN: 0146-9592

We report on a mid-infrared mode-locked fiber laser that uses an acousto-optic tunable filter to achieve frequency-shifted feedback pulse generation with frequency tuning over a 215 nm range. The laser operates on the 3.5 μm transition in erbium-doped zirconium fluoride-based fiber and utilizes the dual-wavelength pumping scheme. Stable, self-starting mode locking with a minimum pulse duration of 53 ps was measured using a two-photon absorption autocor-relator. The longest wavelength demonstrated was 3612 nm, and the maximum average powers achieved were 50 and 167 mW in fundamental and multi-pulse mode-locking regimes, respectively. To the best of our knowledge, this is the longest wavelength rare-earth-doped mode-locked fiber laser demonstrated. The broad tunability promises potential uses for environmental sensing applications.

Journal article

Woodward R, Majewski MR, Macadam N, Hu G, Albrow-Owen T, Hasan T, Jackson SDet al., 2019, Q-switched Dy:ZBLAN fiber lasers beyond 3 mu m: comparison of pulse generation using acousto-optic modulation and inkjet-printed black phosphorus, Publisher: OPTICAL SOC AMER

Working paper

Majewski MR, Woodward R, Jackson SD, 2019, Ultrafast mid-infrared fiber laser mode-locked using frequency-shifted feedback, Publisher: OPTICAL SOC AMER

Working paper

Woodward RI, Majewski MR, Hudson DD, Jackson SDet al., 2019, Swept-wavelength mid-infrared fiber laser for real-time ammonia gas sensing, Publisher: AMER INST PHYSICS

Working paper

Bharathan G, Fernandez TT, Ams M, Woodward R, Hudson DD, Fuerbach Aet al., 2019, Optimized laser-written ZBLAN fiber Bragg gratings with high reflectivity and low loss, OPTICS LETTERS, Vol: 44, Pages: 423-426, ISSN: 0146-9592

Journal article

Woodward R, Majewski MR, Jackson SD, 2018, Mode-locked dysprosium fiber laser: Picosecond pulse generation from 2.97 to 3.30 mu m, APL PHOTONICS, Vol: 3, ISSN: 2378-0967

Journal article

Bharathan G, Hudson DD, Woodward R, Jackson SD, Fuerbach Aet al., 2018, In-fiber polarizer based on a 45-degree tilted fluoride fiber Bragg grating for mid-infrared fiber laser technology, OSA CONTINUUM, Vol: 1, Pages: 56-63, ISSN: 2578-7519

Journal article

Woodward RI, Hudson DD, Fuerbach A, Jackson SDet al., 2018, Few-Cycle Pulse Generation from a 3 μm Fiber Laser

We demonstrate the generation of 70-fs pulses (∼7 optical-cycles) from a mid-infrared mode-locked Ho:ZBLAN fiber laser using nonlinear compression with step-index chalcogenide fiber. Experiments are supported by numerical modelling, confirming the scalability of this approach.

Conference paper

Majewski MR, Woodward RI, Carree JY, Poulain S, Poulain M, Jackson SDet al., 2018, Emission beyond 4 μm and Mid-infrared Lasing from a Dy<sup>3+</sup>:InF<inf>3</inf> Fiber

We present a dysprosium-doped InF3 fiber exhibiting emission beyond 4 microns; the longest wavelength to date from a fluoride-based fiber. Laser emission around 3 μm is also demonstrated.

Conference paper

Majewski MR, Woodward RI, Carree J-Y, Poulain S, Poulain M, Jackson SDet al., 2018, Emission beyond 4 mu m and mid-infrared lasing in a dysprosium-doped indium fluoride (InF3) fiber, OPTICS LETTERS, Vol: 43, Pages: 1926-1929, ISSN: 0146-9592

Journal article

Woodward RI, Majewski MR, Bharathan G, Hudson DD, Fuerbach A, Jackson SDet al., 2018, Watt-level dysprosium fiber laser at 3.15 mu m with 73% slope efficiency, OPTICS LETTERS, Vol: 43, Pages: 1471-1474, ISSN: 0146-9592

Journal article

Majewski MR, Woodward RI, Jackson SD, 2018, Dysprosium-doped ZBLAN fiber laser tunable from 2.8 mu m to 3.4 mu m, pumped at 1.7 mu m, OPTICS LETTERS, Vol: 43, Pages: 971-974, ISSN: 0146-9592

Journal article

Woodward RI, 2018, Dispersion engineering of mode-locked fibre lasers, Photon16, Publisher: IOP Publishing, ISSN: 1464-4258

Mode-locked fibre lasers are important sources of ultrashort pulses, where stable pulse generation is achieved through a balance of periodic amplitude and phase evolutions. A range of distinct cavity pulse dynamics have been revealed, arising from the interplay between dispersion and nonlinearity in addition to dissipative processes such as filtering. This has led to the discovery of numerous novel operating regimes, offering significantly improved laser performance. In this Topical Review, we summarise the main steady-state pulse dynamics reported to date through cavity dispersion engineering, including average solitons, dispersion-managed solitons, dissipative solitons, giant-chirped pulses and similaritons. Characteristic features and the stabilisation mechanism of each regime are described, supported by numerical modelling, in addition to the typical performance and limitations. Opportunities for further pulse energy scaling are discussed, in addition to considering other recent advances including automated self-tuning cavities and fluoride-fibre-based mid-infrared mode-locked lasers.

Conference paper

Woodward RI, Hudson DD, Fuerbach A, Jackson SDet al., 2018, Few-cycle pulse generation from a 3 μm fiber laser

We demonstrate the generation of 70-fs pulses (7 optical-cycles) from a mid-infrared mode-locked Ho:ZBLAN fiber laser using nonlinear compression with stepindex chalcogenide fiber. Experiments are supported by numerical modelling, confirming the scalability of this approach.

Conference paper

Bharathan G, Woodward RI, Hudson DD, Jackson SD, Fuerbach Aet al., 2018, In-fibre polarizer for mid-infrared fibre lasers based on 45° tilted fluoride fibre Bragg grating

We report the femtosecond laser inscription of a 45° tilted fibre Bragg grating (TFBG) into ZBLAN fibre. Integrating this TFBG into a mid-IR fibre laser cavity resulted in 20.5 dB output polarization extinction ratio.

Conference paper

Fuerbach A, Bharathan G, Antipov S, Ams M, Williams RJ, Hudson DD, Woodward RI, Jackson SDet al., 2018, Line-by-line femtosecond FBG inscription for innovative fiber lasers

We report the fabrication of fiber Bragg gratings (FBGs) in passive as well as doped fibers utilizing the femtosecond laser line-by-line technique. Narrow-linewidth linear gratings as well as broadband chirped gratings were inscribed into silica- and fluoride-glass optical fibers. Polarization-dependent characteristics of non-tilted and of 45°-tilted gratings are analyzed and the possibility of direct inscription into coated (i.e. non-stripped) fibers is demonstrated.

Conference paper

Majewski MR, Woodward RI, Jackson SD, 2018, Near infrared pumped full gain bandwidth tunable 3 micron dysprosium fiber laser, Conference on Fiber Lasers XV - Technology and Systems, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

Woodward RI, Majewski MR, Bharathan G, Hudson DD, Fuerbach A, Jackson SDet al., 2018, High-efficiency watt-level mid-infrared fiber lasers beyond 3 µm using Dy:ZBLAN

We demonstrate an optimized in-band-pumped dysprosium fiber laser with 73% slope efficiency and 1.1 W output at 3.15 µm: the first watt-level fiber source in the 3.0-3.4 µm region and highest ever efficiency mid-IR fiber laser.

Conference paper

Woodward RI, Majewski MR, Jackson SD, 2018, Versatile mid-infrared mode-locked fiber laser, electronically tunable from 2.97 to 3.30 µm

We demonstrate the first dysprosium mode-locked laser: the longest wavelength and most widely tunable mode-locked fiber laser to date. Picosecond pulses are generated by a novel frequency-shifted feedback mechanism using an intracavity acousto-optic tunable filter.

Conference paper

Majewski MR, Woodward RI, Carree´ JY, Poulain S, Poulain M, Jackson SDet al., 2018, Emission beyond 4 μm and mid-infrared lasing from a Dy<sup>3+</sup>: InF<inf>3</inf> fiber

We present a dysprosium-doped InF3 fiber exhibiting emission beyond 4 microns; the longest wavelength to date from a fluoride-based fiber. Laser emission around 3 μm is also demonstrated.

Conference paper

Woodward RI, Hudson DD, Jackson SD, 2018, Towards diode-pumped mid-infrared praseodymium-ytterbium-doped fluoride fiber lasers, Conference on Fiber Lasers XV - Technology and Systems, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

Woodward RI, Hudson DD, Fuerbach A, Jackson SDet al., 2017, Generation of 70-fs pulses at 2.86 mu m from a mid-infrared fiber laser, OPTICS LETTERS, Vol: 42, Pages: 4893-4896, ISSN: 0146-9592

Journal article

Bharathan G, Woodward RI, Ams M, Hudson DD, Jackson SD, Fuerbach Aet al., 2017, Direct inscription of Bragg gratings into coated fluoride fibers for widely tunable and robust mid-infrared lasers, OPTICS EXPRESS, Vol: 25, Pages: 30013-30019, ISSN: 1094-4087

Journal article

Hu G, Albrow-Owen T, Jin X, Ali A, Hu Y, Howe RCT, Shehzad K, Yang Z, Zhu X, Woodward RI, Wu T-C, Jussila H, Wu J-B, Peng P, Tan P-H, Sun Z, Kelleher EJR, Zhang M, Xu Y, Hasan Tet al., 2017, Black phosphorus ink formulation for inkjet printing of optoelectronics and photonics, NATURE COMMUNICATIONS, Vol: 8, ISSN: 2041-1723

Journal article

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