Dysprosium (III) ion doped fluoride glass fibre lasers have been demonstrated to generate mid-infrared coherent light with operating wavelength beyond 3000 nm. These devices can also generate mid-infrared optical pulses using both gain and Q-switching. Thus, potentially dysprosium (III) ion doped fluoride glass fibre lasers have many potential commercial applications. In this study, we perform numerical analysis of mid-infrared pulse generation by dysprosium (III) ion doped fluoride glass fibre lasers that operate in a pulsed regime using Q-switching. The results obtained using the developed dynamic numerical model are compared with the measurements. The comparison enables explanation of the experimentally observed trends and helps better understanding of the principles of the fibre laser operation.

A realisation of a Q-switched Tm3+-doped fibre laser operating at 1.96 mu m wavelength is reported. The Tm3+-doped fibre was fabricated using a novel multi-ring modified chemical vapour deposition-chelate doping technique (MCVD-CDT) technology. The developed laser emits pulses at a repetition rate of 3 kHz with an energy of 84 mu J and a duration of 272 ns, which corresponds to a peak power of 309 W. The experimental results confirm that the fabricated Tm3+-doped multi-ring, large mode area fibre is a promising candidate for developing high-energy Q-switched lasers operating near 2 mu m wavelength.

This paper introduces quantum key distribution-as-a-service (QKDaaS) to address the end-to-end security challenges posed by the involvement of multiple orchestrators in 6G networks. These networks require seamless coordination of processes from endpoints to services, with tiered components supporting data-driven and cross-layer predictive procedures. While multi-party (spanning multiple domains, tenants, and providers) enhances local security through advanced controls, it also complicates the implementation of an end-to-end security framework that is essential for mobile network operators. To address this issue, we propose QKDaaS, a secure platform that leverages a fibre transport network for credential and encryption key distribution in multi-party environments. The solution uses wavelength multiplexing to integrate quantum and classical channels within a single fibre. Both C-band and O-band quantum channels are considered, with classical communication in the C-band. The simulation results show that with the currently available experimental setup and mobile network requirements, secure keys can be generated for distances approaching 100 km in the C-band and 60 km in the O-band case. This means that QKDaaS can be deployed in mobile network operators’ current transport infrastructures.

Chalcogenide selenide glass fibres have been demonstrated to be well suited for realising lasers operating beyond 5000 nm wavelength with output powers exceeding 100 mW in CW. These devices have many potential commercial applications because they can be in principle tuned over a wide range of wavelengths and can also be potentially made to generate short optical pulses. Therefore in this paper we use a numerical model to study the energy level population dynamics in terbium doped chalcogenide selenide glass fibre under pulsed pumping. The results obtained further the understanding of major dynamic processes governing a mid-infrared pulse generation by a chalcogenide selenide glass host.

A laboratory realization of an actively Q-switched Dy3+-doped fluoride fiber laser operating near 3.0 mu m is reported. Two laser cavities were realized: one based on 1000 ppm Dy3+:ZBLAN fiber and one on 2000 ppm Dy3+:ZBLAN fiber. With the laser cavity based on 1000 ppm Dy3+:ZBLAN fiber a record high peak power of 200 W was achieved with 17 mu J pulse energy and 84.5 ns pulse duration. Moreover, a record short pulse duration of 74 ns was achieved using Q-switched laser cavity composed of 2000 ppm Dy3+:ZBLAN fiber.

Nanoplasmonics as enabler of room-temperature quantum nanophotonic networks (Invited), Ortwin Hess Coffee break (11:00 -11:20) Track 1 -Room 2.1 Track 2 -Room 2.2 Track 3 -Room 2.3 Track 4 -Room 3.1 Track 5 -Room 3.2 Track 6

Pulsed fluoride glass fibre based lasers have many potential important applications in materials processing, medicine and defence. At present a number of continuous wave fluoride glass fibre lasers is offered commercially. However, there is still a large scope for the development of pulsed lasers. Therefore, in this contribution we give an up-to-date review of the recent progress in the development of gain switched and Q-switched fluoride glass fibre lasers. Also, we present new experimental results on dysprosium ion doped Q-switched fluoride glass fibre lasers.

In this contribution a comprehensive spectroscopic study of Dy3+ doped fluoroindate glass samples and glass fiber is presented. The mid-infrared (MIR) emission from DyF3 doped bulk glass samples (0.2, 0.4, 0.8, 1.2, 1.4, 1.6 mol.%) is investigated when pumping at 1320 nm. A broadband mid-infrared emission spanning from 2800 nm to 3500 nm with 0.88 ms emission lifetime of the 6H13/2 level in 0.2 mol.% glass sample was observed. Also 0.2 mol.% of DyF3 doped fluoroindate glass fiber was drawn and its photoluminescence properties were studied showing the emission spectrum to 3500 nm and the 6H13/2 level lifetime of 0.91 ms. The results obtained show that fluoroindate glass is a good candidate for further development of tunable fiber lasers and broadband mid-infrared spontaneous emission fiber sources.

Mid-infrared lasers operating near 3 µm are a subject of considerable research effort in recent years. The main reason is the broad range of potential applications for such sources in the field of medicine, environmental monitoring and free space communication. For many applications pulsed mid-infrared light sources with high output energy, short pulse duration (to reduce the impact of thermal background) and good pulse-to-pulse stability are preferred. A promising candidate for such pulsed light sources is a mid-infrared fiber laser realised using fluoride glass fibers doped with rare earth ions (for example erbium or dysprosium). In this contribution pulsed operation was obtained by implementing the Q-switching technique in a laser setup consisting of a fluoride fiber pumped with near infrared laser diodes. The obtained pulses have output energy above 100 µJ, with pulse width below 50 ns and repetition rate in the kilohertz range.

A practical realization of a diode pumped actively Q-switched Er 3+ -doped fluoride fiber laser operating near 2.78 μm is reported. For the repetition rate of 100 Hz stable 26 ns pulses with an energy of 330 μJ and peak power of 12.7 kW are demonstrated. The laser performance is tested against variations in pump power, repetition rate and active fiber length.

In this contribution the diode pumped high-power Er:ZBLAN laser operating at around 2.8 µm is reported. The laser produces 2 W output power with the slope efficiency of 24 % measured with respect to the incident pump power. Full Text: PDF ReferencesS. D. Jackson, "Towards high-power mid-infrared emission from a fibre laser", Nature Photonics 6, 423 (2012). CrossRef V. Portosi, D. Laneve, C. M. Falconi, and F. Prudenzano, "Advances on Photonic Crystal Fiber Sensors and Applications", Sensors 19, (2019). CrossRef M. C. Falconi, D. Laneve, and F. Prudenzano, "Advances in Mid-IR Fiber Lasers: Tellurite, Fluoride and Chalcogenide", Fibers 5, 23 (2017). CrossRef M. Michalska, P. Grześ, J. Świderski, "High power, 100 W-class, thulium-doped all-fiber lasers", Phot. Lett. Poland, 11, 109 (2019). CrossRef Y. O. Aydin, V. Fortin, R. Vallée, and M. Bernier, "Towards power scaling of 2.8 μm fiber lasers", Opt. Lett. 43, 4542 (2018). CrossRef S. Crawford, D. D. Hudson, and S. D. Jackson, "High-Power Broadly Tunable 3- μm Fiber Laser for the Measurement of Optical Fiber Loss", IEEE Photonics Journal 7, 1 (2015). CrossRef V. Fortin, F. Jobin, M. Larose, M. Bernier, and R. Vallée, "10-W-level monolithic dysprosium-doped fiber laser at 3.24 μm", Opt. Lett. 44, 491 (2019). CrossRef L. Sójka, et al., "Experimental Investigation of Mid-Infrared Laser Action From Dy3+ Doped Fluorozirconate Fiber", IEEE Photon. Technol. Lett. 30, 1083 (2018). CrossRef M. Pollnan and S. D. Jackson, "Erbium 3 /spl mu/m fiber lasers", IEEE J. Sel. Top. in Quantum Electron., 7, 30 (2001). CrossRef Y. O. Aydin, F. Maes, V. Fortin, S. T. Bah, R. Vallée, and M. Bernier, "Endcapping of high-power 3 µm fiber lasers", Opt. Express 27, 20659 (2019). CrossRef C. A. Schäfer, "Fluoride-fiber-based side-pump coupler for high-power fiber lasers at 2.8 μm", et al., Opt. Lett. 43, 2340 (2018). CrossRef O. Henderson-Sapir, J. Munch, and D. J. Ottaway, "New energy-transfer upconversion process in Er3+:ZBLAN mid-infrared fiber lasers", Opt. Express 24, 6869 (2016). CrossRef F. Maes, V. Fortin, S. Poulain, M. Poulain, J.-Y. Carrée, M. Bernier, and R. Vallée, "Room-temperature fiber laser at 3.92 μm", Optica 5, 761 (2018). CrossRef R. I. Woodward, M. R. Majewski, D. D. Hudson, and S. D. Jackson, "Swept-wavelength mid-infrared fiber laser for real-time ammonia gas sensing", APL Photonics 4, 020801 (2019). CrossRef M. Kochanowicz, et al., "Near-IR and mid-IR luminescence and energy transfer in fluoroindate glasses co-doped with Er3+/Tm3+", Opt. Mater. Express 9, 4772 (2019). CrossRef M. Kochanowicz, et al., "Sensitization of Ho3+ - doped fluoroindate glasses for near and mid-infrared emission", Optical Materials 101, 109707 (2020). CrossRef J. Wang, X. Zhu, M. Mollaee, J. Zong, and N. Peyhambarian, "Efficient energy transfer from Er3+ to Ho3+ and Dy3+ in ZBLAN glass", Opt. Express 28, 5189 (2020). CrossRef M. C. Falconi, D. Laneve, V. Portosi, S. Taccheo, and F. Prudenzano, "Design of a Multi-Wavelength Fiber Laser Based on Tm:Er:Yb:Ho Co-Doped Germanate Glass", J Lightwave Technol 1 (2020). CrossRef K. Anders, A. Jusza, P. Komorowski, P. Andrejuk, and R. Piramidowicz, "Short wavelength up-converted emission studies in Er3+ and Yb3+ doped ZBLAN glasses", J. Lumin. 201, 427 (2018). CrossRef P. Komorowski ,K. Anders ,U. Zdulska,R. Piramidowicz R. "Erbium doped ZBLAN fiber laser operating in the visible - feasibility study", Photonics Lett Pol 9, 85 (2017). CrossRef J. Swiderski, M. Michalska, and P. Grzes, "Broadband and top-flat mid-infrared supercontinuum generation with 3.52 W time-averaged power in a ZBLAN fiber directly pumped by a 2-µm mode-locked fiber laser and amplifier", Applied Physics B 124, 152 (2018). CrossRef V. Fortin, M. Bernier, S. T. Bah, and R. Vallée, "30 W fluoride glass all-fiber laser at 2.94 μm", Opt. Lett. 40, 2882 (2015). CrossRef

A diode-pumped Q-switched Er3+:ZBLAN double-clad, single-transverse mode fiber laser is practically realized. The Q-switched laser characteristics as a function of pump power, repetition rate, and fiber length are experimentally investigated. The results obtained show that the Q-switched operation with 46 µJ pulse energy, 56 ns long pulses, and 0.821 kW peak power is achieved at a pulse repetition rate of 10 kHz. To the best of our knowledge, this is the highest-ever demonstrated peak power emitted from an actively Q-switched, single-transverse mode Er3+:ZBLAN fiber laser operating near 2.8 µm.

Practical realization of gain-switched Dy 3+ -doped ZBLAN fiber laser operating at 2.94 μm is reported. The laser is pumped by a 1.1 μm Q-switched ytterbium (III) fiber laser, which was constructed in-house. The ZBLAN fiber laser generates a stable pulse train with repetition rates spanning the range from 25 to 100 kHz. At the repetition rate of 50 kHz, the pulse width is 183 ns while energy and peak power are 0.72 μJ and 4 W, respectively.

A fiber ring laser sensor setup utilizing fiber Bragg gratings (FBGs) for simultaneous measurement of ambient temperature and relative humidity (RH) is presented. Two FBGs are incorporated as tunable filters for a dual-wavelength laser emission, where one FBG was coated with polyimide (PI) in order to achieve sensitivity to RH changes, while the other bare FBG was used for temperature sensing. An increase in RH would induce a strain on the grating, which results in a variation in the resonance wavelength of the PI-coated FBG. This causes a shift in the laser emission wavelength. Being insensitive to RH changes, the bare FBG was employed to measure temperature. The dual-wavelength fiber ring laser sensor created, and thus allows to determine simultaneous measurement of RH and temperature. The RH sensitivities observed by the PI-coated FBG to RH and temperature are 3.6 pm/%RH and 12.15 pm/°C. The temperature sensitivity of the bare FBG was observed to be 9.6 pm/°C. The main advantage of the proposed setup is an optical signal to noise ratio (OSNR) higher than 55 db 3 dB bandwidth less than 0.02 nm, which points out efficient capabilities for both precise sensing and remote detection applications.

Abstract A gain-switched Dy3+-doped ZBLAN fiber laser operating at 2.943 μm is experimentally reported for the first time to the best of our knowledge. The laser was pumped by a 1.1 μm Q-switched ytterbium (III) fiber laser constructed in-house. A stable pulse train is achieved with repetition rates spanning between 25 and 100 kHz. For the repetition rate of 50 kHz, stable 183 ns pulses with an energy of 0.72 μJ and peak power of 4 W are recorded. By using a longer length of Dy3+-doped ZBLAN fiber, gain-switched operation was achieved at a wavelength larger than 3 μm.

A gain-switched Dy3+-doped ZBLAN fiber laser operating at 2.943 mu m is experimentally reported for the first time to the best of our knowledge. The laser was pumped by a 1.1 mu m Q-switched ytterbium (III) fiber laser constructed in-house. A stable pulse train is achieved with repetition rates spanning between 25 and 100 kHz. For the repetition rate of 50 kHz, stable 183 ns pulses with an energy of 0.72 mu J and peak power of 4 W are recorded. By using a longer length of Dy3+-doped ZBLAN fiber, gain-switched operation was achieved at a wavelength larger than 3 mu m.

Efficient continuous-wave laser operation at 2.982 mu m is achieved with a Dy3+:fluoride fiber pumped using an inhouse-built 1.1 mu m ytterbium (III) fiber laser. The laser output power reached is 554 mW, with a maximum slope efficiency of 18% with respect to the launched pump power. Additionally, the measured spontaneous luminescence within the visible wavelength range, under 1.1 mu m pumping, is presented and attributed to excited state absorption (ESA). The influence of the ESA on the laser performance is discussed. The results confirm that high output powers from Dy:fluoride fiber laser pumped at 1.1 mu m are possible.

This paper presents investigation of normal and cancerous tissue by the means of one and two photon fluorescence spectroscopy. A comparison those methods has been conducted, allowing for eventual determination of granting the best possible diagnostic results.