Optical Communications: The Beginning

The first efforts by Alexander Graham Bell at optical communications by incoherent light are discussed. Those were very inefficient at the time but after the invention of the laser it was only a question of time when coherent optical communication will dominate the communications scene The beginning was slow because propagation both in air and in fibre waveguide was too large. Enormous efforts by the Corning Glass Works brought down the attenuation to a figure as low as a few dbs per kilometre making some further applications feasible. The next break-through was the invention of the fibre amplifier enabling the erection of long relay-free lines (maybe up to 10,000 km) possible range of applications was greatly extended by the invention of the fibre amplifier. Coherent light propagation in thin, single-mode fibres is discussed a very thin fibre is discussed. It is shown that an optical fibre can carry an enormous number of communication channels. The laser was invented just in time to help produce the signals, and it also became possible to produce pure enough glass fibres in which an optical signal could propagate with low attenuation. The invention of erbium-doped fibre amplifiers allowed them to be spread all over the world, including large number of lines under the oceans.

Synthesis, Structural and Luminescence Studies of Europium Doped Borate Glasses

Different concentration of (0.1, 0.2, 0.3, 0.4, 0.5, 1.0 & 1.5) mol% of europium doped lead borate lithium glasses were prepared by melt quenching method. The properties of thermal, photoluminescence & structural were analyzed using DTA, FTIR and emission spectra. Emission spectra was used to evaluate the Judd-Ofelt (JO) parameters. Radiative parameters like stimulated emission cross-sections (σe), effective band width (∆λeff), transition probabilities (A), optical gain bandwidths (σe x ∆λeff), radiative lifetime (τrad) and optical gain (σe x τrad) values were evaluated for the transition 5D0→7Fj (j=1, 2, 3 and 4) of Eu3+ ions. The outcome of transition 5D0→7F4 at its highest value of branching ratios and stimulated emission cross-section are evaluated with the literature. Hence we can could the prepared host glass doped with Eu3+ ions are good fibre amplifiers and it can be used as a red laser.

High power, 100 W-class, thulium-doped all-fiber lasers

In this work, sub-kilowatt, compact thulium-doped fiber laser systems, operating at a wavelength of 1940 nm, have been presented. The continuous-wave laser power generated out of a single oscillator was 90 W with a slope efficiency of 56.7%. Applying a master oscillator – power amplifier configuration, an output power of 120.5 W with a slope efficiency of 58.2% was demonstrated. These are the first results of the works aimed at developing kW-class “eye-safe” laser systems in Poland. Full Text: PDF ReferencesZ. Liu, et al., "Implementing termination analysis on quantum programming", Sci. China Inf. Sci. 62, 41301 (2019) CrossRef S. D. Jackson, A. Sabella, D.G Lancaster, "Application and Development of High-Power and Highly Efficient Silica-Based Fiber Lasers Operating at 2 μm", IEEE J. Sel. Top. Quantum Electron. 13, 567, (2007). CrossRef E. Russell, N. Kavanagh, K. Shortiss, and F. C. G. Gunning, "Development of thulium-doped fibre amplifiers for the 2μm waveband", Proc. SPIE 10683, 106832Q (2018) CrossRef P. Peterka, B. Faure, W. Blanc, M. Karásek, and B. Dussardier, "Theoretical modelling of S-band thulium-doped silica fibre amplifiers", Opt. Quantum Electron. 36, 201 (2004) CrossRef M. Eichhorn, "Pulsed 2 μm fiber lasers for direct and pumping applications in defence and security", Proc. SPIE 7836, 78360B (2010). CrossRef O. Traxer and E. X. Keller, "Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser", World J. Urol. 2019 Feb 6. doi: 10.1007/s00345-019-02654-5 CrossRef S. Das, "Optical parametric oscillator: status of tunable radiation in mid-IR to IR spectral range based on ZnGeP2 crystal pumped by solid state lasers", Opt. Quant. Electron. 51, 70 (2019) CrossRef M. Michalska, P. Hlubina, and J. Swiderski, "Mid-infrared Supercontinuum Generation to ∼4.7 μm in a ZBLAN Fiber Pumped by an Optical Parametric Generator", IEEE Photon. J 9, 3200207 (2017) CrossRef https://www.ipgphotonics.com DirectLink M.D. Burns, P. C. Shardlow, P. Barua, T. L. Jefferson-Brain, J. K. Sahu, and W. A.Clarkson, "47 W continuous-wave 1726 nm thulium fiber laser core-pumped by an erbium fiber laser", Opt. Lett. 44, 5230 (2019) CrossRef S.D. Jackson, "Cross relaxation and energy transfer upconversion processes relevant to the functioning of 2 μm Tm3+-doped silica fibre lasers", Opt. Commun. 230, 197 (2004). CrossRef X. Wang, P. Zhou, X. Wang, H. Xiao, and L. Si, "102 W monolithic single frequency Tm-doped fiber MOPA", Opt. Express 21, 32386 (2013) CrossRef K. Yin, R. Zhu, B. Zhang, G. Liu, P. Zhou, and J. Hou, "300 W-level, wavelength-widely-tunable, all-fiber integrated thulium-doped fiber laser", Opt. Express 24, 11085 (2016) CrossRef G. D. Goodno, L. D. Book, and J. E. Rothenberg, "600-W, single-mode, single-frequency thulium fibre laser amplifier", Proc. SPIE 7195, 71950Y (2009). CrossRef T. Ehrenreich, R. Leveille, I. Majid, K. Tankala, G. Rines, and P. Moulton, "1-kW, all-glass Tm: fiber laser", Proc. SPIE 7580, 1 (2010) DirectLink M. Michalska et al., "Highly stable, efficient Tm-doped fiber laser—a potential scalpel for low invasive surgery", Laser Phys. Lett. 13, 115101 (2016). CrossRef