Bor Chyuan Hwang

Er3+-doped phosphate glasses for fiber amplifiers with high gain per unit length

The effect of the types of alkaline earth metal ions (Mg 2+ , Ca 2+ and Ba 2+ ) and concentration of Al 2 O 3 and BaO on the refractive index and the effective emission linewidths of the 4 I 13/2 - 4 I 15/2 transition of Er 3+ ions in phosphate glasses, 64P 2 O 5 . 12Al 2 O 3 . 3.5(Er 2 O 3 + La 2 O 3 ) . 20.5MO (M = Mg, Ca, Ba) and 64P 2 O 5 . 3.5(Er 2 O 3 + La 2 O 3 ) . (21.5-x)Al 2 O 3 . (11 +x)BaO (x =0, 3.5, 6.5 and 9.5), were investigated. A single mode Er 3 doped phosphate glass fiber with a core diameter of 4 μm was fabricated by the rod-in-tube technique. A new Er 3+ doped fiber amplifier is demonstrated pumping with a 980 nm fiber pigtailed-laser diode. A gain per unit length greater than 2 dB/cm is demonstrated, which is the largest gain per unit length for fiber amplifiers to our knowledge.

Spectral properties of erbium-doped lead halotellurite glasses for 1.5 μm broadband amplification

Abstract The spectral properties of the Er 3+ -doped lead halotellurite glasses, PbX 2 –TeO 2 (X=F, Cl, Br), were measured and analyzed with Judd-Ofelt and McCumber theories. These glasses showed high refractive indices, high cross-sections for both absorption and stimulated emission, and very broad bandwidths for the 1.5 μm band. The bandwidths of the 1.5 μm band, which have substantial magnetic dipole transition component, increased significantly with the refractive index of the host materials. The halotellurite glasses have very good glass formation ability or glass stability. The halotellurite glasses will be the promising host materials for 1.5 μm broadband amplification.

Effect of relative alkali content on absorption linewidth in erbium-doped tellurite glasses

Er 3+ doped tellurite glasses with various Na 2 O/Li 2 O, Na 2 O/K 2 O and K 2 O/Li 2 O ratios (0-4.5) were prepared at 850°C using a platinum crucible. The effect of relative alkali content on absorption linewidth in erbium-doped tellurite glasses was investigated. The highest effective linewidth was obtained from glass samples with mixed alkali molar ratio of Na 2 O/Li 2 O=1, Na 2 O/K 2 O=1 and K 2 O/Li 2 O=1. Glass transition temperature, crystallization temperature, density, refractive index, Judd-Ofelt parameters and emission cross-section of Er 3+ doped tellurite glasses are also reported.

New Er3+-doped phosphate glass for ion-exchanged waveguide amplifiers

A new Er 31 -doped phosphate glass exhibiting an excellent durability in both boiling water and NaNO3 molten salt is developed. The ion-exchange process of this glass is investigated by treating glass samples in a variety of salt baths with various exposure times. A planar waveguide with one mode at 1.54 mm and three modes at 632.8 nm is demonstrated. The spectral properties of Er 31 in this glass are charac- terized by measuring absorption and emission spectra and fluorescence lifetimes. The emission cross section of Er 31 in this glass is calculated to be 0.76310 20 cm 2 using McCumber theory.

Spectral properties of erbium-doped lead halotellurite glasses

Broadband erbium-doped fiber amplifiers at 1.5 micrometers band, an important communication band, are generating great interest in order to increase the transmission capacity of wavelength-division-multiplexing transmission networks. The host materials for Er3+ doping are very important for obtaining an intrinsically broad amplifier bandwidth. This paper reports the spectral properties of the Er3+ doped lead halotellurite glasses, PbX2-TeO2 (X equals F, Cl, Br). The measured absorption and emission spectra were analyzed by Judd-Ofelt and McCumber theories. It was found that Er3+ doped lead halotellurite glasses have a good glass stability, high refractive indices, high absorption and stimulated emission cross sections, and a very broad bandwidth for 1.5 micrometers absorption and emission. The 1.5 micrometers band, which has a substantial magnetic dipole transition component, is a special band whose bandwidth increases significantly with the refractive index of the host material. It is expected that the halotellurite glasses will be the promising host materials for 1.5 micrometers broadband amplification.

Characterization of cooperative upconversion and energy transfer of Er3+ and Yb3+/Er3+ doped phosphate glasses

Cooperative upconversion and Yb3+-Er3+ energy transfer in newly developed phosphate glasses were studied in this paper. The cooperative upconversion coefficients of 4I13/2 level for different Er3+ concentrations were deduced from the pump intensity- dependent luminescence decay curves. Yb3+-Er3+ energy transfer efficiencies for different Yb3+ concentrations codoped with Er3+ (approximately 2 X 1020 ions/cm3) were estimated from the lifetime measurements of 2F5/2 level of Yb3+ ions. The small cooperative upconversion coefficients and high Yb3+-Er3+ energy transfer efficiencies indicate these newly developed Er3+ and Yb3+/Er3+ doped phosphate glasses are excellent for amplifier and laser applications.

Erbium-doped tellurite glasses for 1.5-um broadband amplification

Er

Rate equation analyses and energy transfer of Er3+-doped sulfide glasses

3+) doped tellurite glasses with various Na2O/Li2O, Na2O/K2O and K2O/Li2O ratios were prepared. Absorption and emission spectra, glass transition temperatures, crystallization temperatures, densities, and refractive index of these glass samples were characterized. For all studied glass samples, the highest effective linewidth was obtained with mixed alkali molar ratio of Na2O/Li2O equals 1, Na2O/K2O equals 1 and K2O/Li2O equals 1. The studied glasses have a (Tx- Tg) exceeding 100 degree(s)C, indicating these glass samples are stable against devitrification. In addition, Judd-Ofelt analysis of several glasses was also performed.

Cooperative upconversion and energy transfer of new high Er 3+ - and Yb 3+ –Er 3+ -doped phosphate glasses

Decay curves of 1.5 micrometers (4I13/2) and 980 nm (4I11/2) emissions from Er3+ ions in Ga2S3-GeS2-La2S3 glasses were measured by the excitation of 1.5 micrometers laser diode pump. The decay curves were simulated using rate equations for a model consisting of four levels (4I15/2, 4I13/2, 4I11/2, and 4I9/2) of Er3+. A pair of unknown parameters, i.e., an excited state absorption coefficients for 4I13/2 yields 4I9/2, (sigma) esa, and a cooperative upconversion coefficient for (4I13/2, 4I13/2) yields (4I9/2, 4I15/2), C, were included in the rate equations. They were estimated by fitting the simulated curves to the measured ones. The obtained values were 3 X 10-21 cm2 and 1 or 3 X 10-21 cm3/s for the (sigma) esa and C, respectively.