Shaoxiong Shen

Broadband emission in Er 3+ -Tm 3+ codoped tellurite fibre

The visible and near infrared emission spectra of Er(3+)-Tm3(3+)-codoped tellurite glasses and fibres were measured with the excitation of an 800 nm laser. A broad emission extending from 1.35 mum to 1.6 mum with a full width at half-maximum (FWHM) of ~160 nm was recorded in a 24 cm long 0.2 wt% Er(2)O(3) and 1.0 wt% Tm(2)O(3) codoped tellurite fibre. Energy transfer between Er(3+) and Tm(3+) play important roles in the luminescence mechanism. These results indicate that Er(3+)-Tm(3+) codoped tellurite fibre could be a promising material for broadband light source and broadband amplifier for the wavelength-division-multiplexing (WDM) transmission systems.

Tm 3+ -doped tellurite glass for a broadband amplifier at 1.47 µm

Tm(3+)-doped tellurite glass is investigated as a host for a broadband amplifier at 1.47 mum. The Tm(3+) fluorescence spectrum, lifetime, and cross section in tellurite glass are compared with those in fluorozirconate glasses. The advantages of a Tm(3+)-tellurite amplifier, especially when it is employed in combination with an Er(3+)-tellurite 1.55-mum amplifier, are discussed.

Infrared emission and energy transfer in Tm 3+ , Tm 3+ -Ho 3+ and Tm 3+ -Yb 3+ -doped tellurite fibre

The infrared emission spectra and decay lifetimes of Tm(3+)-doped and Tm(3+)-Ho(3+), Tm(3+)-Yb(3+) co-doped tellurite fibres were measured using 808 nm and 978 nm diode laser pump sources in the range 1.35 mum to 2.2 mum. The spectra were compared with varying fibre lengths and core diameters. Tm(3+)-doped fibre shows strong emission at ~1.8 mum and when co-doped with Ho(3+), energy transfer results in strong Ho(3+) fluorescence at ~2.0 mum. These fibres show promise for compact mid-IR fibre laser sources.

Tungsten–tellurite—a host glass for broadband EDFA

Abstract Tungsten–tellurite glass is proposed as a host for broadband erbium-doped fibre amplifiers (EDFA). The spectroscopic properties of Er 3+ -doped tungsten–tellurite glass are described, and a broad 1.5 μm emission spectrum of 85 nm FWHM is demonstrated. The suitability of tungsten–tellurite glass as a host for EDFA and its advantages over tellurite are discussed.

Er:Yb-doped oxyfluoride silicate glass waveguide amplifier fabricated using femtosecond laser inscription

The authors report net gain from a channel waveguide fabricated in an Er:Yb-doped oxyfluoride silicate glass substrate using femtosecond laser waveguide inscription. To fabricate waveguides exhibiting low propagation and coupling losses, they used the recently demonstrated multiscan technique that allows the waveguide cross section and refractive index contrast to be controlled independently of each other. By doing so, the best waveguide exhibited a total background insertion loss, excluding absorption, of only 1.2dB at 1537nm. As a result, a fiber-fiber net gain of 0.72dB at 1537nm was measured for a 10mm long waveguide.The authors report net gain from a channel waveguide fabricated in an Er:Yb-doped oxyfluoride silicate glass substrate using femtosecond laser waveguide inscription. To fabricate waveguides exhibiting low propagation and coupling losses, they used the recently demonstrated multiscan technique that allows the waveguide cross section and refractive index contrast to be controlled independently of each other. By doing so, the best waveguide exhibited a total background insertion loss, excluding absorption, of only 1.2dB at 1537nm. As a result, a fiber-fiber net gain of 0.72dB at 1537nm was measured for a 10mm long waveguide.

Enhancement in pump inversion efficiency at 980 nm in Er 3+ , Er 3+ /Eu 3+ and Er 3+ /Ce 3+ doped tellurite glass fibers

Amplification properties have been compared in Er(3+), Er(3+)/Eu(3+) and Er(3+)/Ce(3+) doped tellurite glass fibers using a 980 nm pumping scheme. The pump efficiency has been compared in the 3 types of fibers. Er(3+) ion upconversion in bulk glasses and fibers in visible range has been measured and the Er(3+) ion IR fluorescence intensity and lifetimes have been recorded to understand the amplification characteristics. Codoping with Ce3+ is more efficient in Er(3+) doped tellurite fibre.

Supercontinuum generation in an ultrafast laser inscribed chalcogenide glass waveguide.

We report on the fabrication and characterisation of waveguides fabricated in a GeS based chalcogenide glass. A wide range of waveguiding structures were fabricated, and supercontinuum generation was demonstrated for a highly multimode waveguide.

Er3+-doped boro-tellurite glass for optical amplification in the 1530–1580nm

The paper investigates the influence of boric oxide (B2O3), which has a phonon energy of 1500cm−1, on enhancement in the population of the I13∕24 level via the increased multiphonon relaxation in the Er-ion doped tellurite fibers. The paper discusses the structural compatibility of TeO4 structures with BO4 structural units and, therefore, the limitation on the solubility limits of boric oxide in the glass. In the present investigation the optimal composition demonstrates the minimum devitrification tendency in the glassy state that has one of the largest multiphonon relaxation rates. A comparison of lifetimes of I11∕24 level is also made for other tellurite and boro-tellurite compositions. The experimental data show that the transition rate at I11∕24→I13∕24 dramatically increased by incorporating 15mol% B2O3 without sacrificing the spectroscopic properties of glass. The lifetime at I11∕24 transition level decreased from 213to54μs when B2O3 is introduced into tellurite glass. We also report the calculated ...

Enhanced room-temperature emission in Cr4+ ions containing alumino-silicate glasses

The Bi2O3 modified alumino-silicate glasses, when excited at 800 nm exhibited a broadband emission of Cr4+ in the range of 1.2 to ∼1.6 μm at room temperature. The mean lifetime of (1E−3A2)→3T1 transition in Cr4+-doped glass at RT was as long as ∼426 μs, enabling the realization of both tunable lasers and broadband fiber amplifiers. The Cr4+ emission at RT also showed the dependency on the excitation wavelength and site distribution within the chosen glass host. A photoinduced charge transfer process from the Cr3+ ion into Cr4+ ion appears to be responsible for the excitation of Cr4+.

Femtosecond laser inscription of optical waveguides in Bismuth ion doped glass

We report on the fabrication of high quality embedded channel waveguides inside Bi-doped silicate glass using femtosecond waveguide inscription. Waveguides are fabricated using both single and multi-scan fabrication techniques. Refractive index modifications of up to ∆n = 4.3×10-3 are observed, allowing the fabrication of waveguides nearly mode-matched to telecom fibers. When optically pumped at 980 and 810 nm broadband fluorescence emission centered at 1.3 μm with a FWHM of up to 500 nm is detected.