1 Bi-doped Fiber Lasers: Opportunities and Challenges E. M. Dianov Fiber Optics Research Center of the Russian Academy of Sciences, 38 Vavilov str., Moscow , Russia.

2 Outline Introduction Spectroscopic properties of Bi-doped glasses and optical fibers Bi-doped fiber lasers ( nm) Bi-doped fiber lasers ( nm) Nature of Bi-related luminescent centers Conclusion

3 Волоконные лазеры 1 кВт Преимущества: эффективность (более 30%) качество пучка надежность и простота в эксплуатации размеры и вес рынок волоконных лазеров в 2007 году  10 6 долларов США ожидается удвоение рынка в 2011 году

4 Spectral regions of the existing fiber lasers

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6 Transmission and luminescence spectra of Bi- doped silica glass (Fujimoto and Nakatsuka, 2001) 97.5SiO Al 2 O Bi 2 O 3

7 Luminescence properties of various Bi-doped materials p, e – pump and emission peak wavelengths,  – lifetime of Bi luminescence. NComposition (mol%)λp (nm)λe (nm) FWHM (nm) τ (μs)References 196GeO 2 – 3Al 2 O 3 – 1Bi 2 O M.Peng et al., SiO 2 -23Al 2 O 3 -13Li 2 O-1Bi 2 O Suzuki and Ohishi, SiO 2 -30GeO 2 -15MgO-5Al 2 O 3 -1Bi 2 O J.Ren et al., P 2 O 5 -12B 2 O 3 -15La 2 O 3 -6Al 2 O 3 -17Li 2 O- 1Bi 2 O B.Denker et al., GeS Ga 2 S KBr-0.5Bi 2 O G.Yang et al., RbPb 2 Cl 5 :Bi crystal ~ A. Okhrimchuk et al., 2008

8 Compositions of fabricated fibers and their absorption spectra (FORC) #Core glass composition, mol.%Bi concentration, at.%, and doping technique Loss at 1000 nm, dB/m 1SiO 2 -1Al 2 O GeO P 2 O 5 <0.02, solution0.2 4SiO 2 -15Al 2 O GeO 2 <0.02, solution2.1 5SiO Al 2 O , solution≈20 17SiO 2 -5Al 2 O GeO 2 <0.02, vapor2.2 25SiO 2 -2Al 2 O 3 <0.02, vapor SiO 2 -5Al 2 O 3 <0.02, solution GeO 2 -19SiO 2 -5Ta 2 O 5 -1P 2 O 5 <0.02, vapor~0.02 The first low loss Bi-doped optical fibers: V.V.Dvoyrin et al., (FORC, ICHPS), ECOC’2005 T.Haruna et al., (Sumitomo), OAA’2005

9 Compositions of fabricated fibers and their luminescence spectra #Core glass composition, mol.%Bi concentration, at.%, and doping technique Loss at 1000 nm, dB/m 1SiO 2 -1Al 2 O GeO P 2 O 5 <0.02, solution0.2 4SiO 2 -15Al 2 O GeO 2 <0.02, solution2.1 5SiO Al 2 O , solution≈20 17SiO 2 -5Al 2 O GeO 2 <0.02, vapor2.2 25SiO 2 -2Al 2 O 3 <0.02, vapor SiO 2 -5Al 2 O 3 <0.02, solution GeO 2 -19SiO 2 -5Ta 2 O 5 -1P 2 O 5 <0.02, vapor~0.02

10 Luminescence spectra of Bi-doped silica glass and MCVD fibers pumped at 800 nm. Sumitomo

11 Bi-doped fiber lasers ( nm) 1.E.M.Dianov et al. “CW bismuth fiber laser”, Quant. Electron. 2005; OFC’ E.M.Dianov et al. “Yellow frequency-doubled bismuth fiber laser”, ECOC’ V.V.Dvoyrin et al. “Yb-Bi pulsed fiber laser”, Opt.Lett., A.A.Krylov et al., “A mode-locked Bi-doped fiber laser”, OFC’ E.M.Dianov et al. “High-power CW bismuth fiber laser”, OFC’2007, JOSA B, I.Razdobreev et al. “Efficient all-fiber bismuth-doped fiber laser”, Appl. Phys. Lett., A.B.Rulkov et al. “Narrow-line 1178 nm CW bismuth –doped fiber laser with 6.4 W output for direct frequency doubling”, Opt. Express, V.V.Dvoyrin et al. “Effective Bi fiber lasers”, IEEE J.QE, V.M. Mashinsky, V.V. Dvoyrin, E.M. Dianov. “New Results on the Efficiency of Bismuth Fiber Lasers”, OFC’ S. Yoo et al. “Bismuth-doped Fiber laser at 1.16  m”, CLEO/QELS’ S. Kivistö et al. “Tunable mode-locked bismuth-doped soliton fiber laser”, submitted to Electron. Lett., 2008.

12 Scheme of a Bi-doped fiber laser and the absorption spectrum of the Bi-doped fiber used Bi-doped fiber:  c =1.1  m; Mode field diameter- 6.8  m, bismuth concentration - < 2  at%, l=50-80 m, p =1070 and 1085 nm

13 Efficiency of the Bi-doped fiber laser for four wavelengths and the output spectrum for =1215 nm

14 Output power of the Bi-fiber laser against the fiber temperature at the pump power of 8W

15 Averaged optical losses of the same Bi-doped fiber against launched power at different temperatures

16 15W CW bismuth fiber laser Bandwidth of the Bi laser radiation vs. the output power of the Bi laser.

17 Frequency-doubled bismuth fiber laser Output spectrum of yellow light Motivation: medicine, astrophysics PPLN (Global Fiberoptics, Ltd)

18 Желтый лазер AlInGaAs/InP

19 Bi-doped fibers for the nm spectral region mark Core glass composition, (consentration in mol.%,) aPGSB83.5SiO P 2 O 5 -15GeO 2 bGSB85SiO 2 -15GeO 2 cPSB92.5SiO P 2 O 5 dASB97SiO 2 -3Al 2 O 3 Dianov et al. “Luminescence and lasing of Bi-doped fibers in a spectral region of nm”, submitted to OFC’2009.

20 Emission and gain spectra of PGSB fibers Emission spectra of PGSB fibers pumped 1 at p =1230 nm and 2 p =808 nm; 3 4 Variation of the on/off gain with signal wavelength for a PGSB fiber pumped at 3 fiber length L=30 m p =1230 nm and 4 fiber length L=13 m p =808 nm.

21 I.A. Bufetov et al. “Bi-doped fiber lasers and amplifiers for a spectral region of 1300–1470 nm”, Opt. Lett., 33, (2008) Output emission spectra of Bi-doped fiber lasers

22 Output power of BFLs as a function of absorbed pump power at T=300K The efficiency of the laser at T=77K is shown in brackets.

23 What is a nature of Bi-related centers emitting in near IR? Bi 5+ - Fujimoto and Nakatsuka, 2001 Bi + - X. Meng et al., 2005 BiO – J. Ren et al., 2006 Bi 2, Bi 2 -, Bi Khonthon et al., 2007; Sokolov et al., 2008

24 Sh.Zhou et al, Bi-doped Nanoporous Silica Glass, Adv. Funct. Mater., 18, 1407, 2008 glass A (air) p =280nm, e =465nm (Bi 3+ ) glass B (argon) p =280nm, e =465nm (Bi 3+ ) p =483nm, e =590nm (Bi 2+ ) p =532nm, 980nm, e =1100nm (Bi + ?) p =800nm, e =1400nm (Bi + ?) glass C (hidrogen) no emission

25 B.Denker et al., ”Absorption and emission properties of Bi-doped Mg-Al- Si oxide glass system”, submitted to Appl. Phys. Lett., (2008). Extinction coefficient of Mg-Al-Si glass at the peak wavelength 500 nm versus Bi 2 O 3 concentration

26 M.Yu. Sharonov et al. „Spectroscopic study of optical centers formed in Bi-, Pb-, Sb-, Sn-, Te-, and In-doped germinate glasses“, Opt. Lett., vol. 33, pp , 2008 Fluorescence spectra are vertically shifted for clarity; fluorescence intensity is about zero at 1800 nm for all samples.

27 Conclusion Demonstration of Bi-doped fiber laser generation in a spectral region of nm represents a significant milestone towards producing efficient fiber lasers and wideband optical amplifiers for this spectral region. Unforeseen properties of Bi in glasses might hinder development of practical Bi-doped fiber lasers and amplifiers. Further vast fundamental researches of properties of Bi in glasses are necessary.