NISCAIR Online Periodicals Repository Collection: IJEMS Vol.12(1) [February 2005]

Absorption studies of tripositive praseodymium and neodymium doped zinc fluoride borophosphate (ZFBP) glasses

Sat, 29 Jan 2005 22:58:59 GMT

Title: Absorption studies of tripositive praseodymium and neodymium doped zinc fluoride borophosphate (ZFBP) glasses

Authors: Sharma, Y K; Dubedi, R P; Joshi, V; Karnataka, K B; Surana, S S L

Abstract: Zinc fluoride borophosphate (ZFBP) glasses doped with tripositive praseodymium and neodymium ions have been prepared by melt quenching technique. The final composition of glasses in mol.% is 15.44 B₂O₃ – 39.77 P₂O₅ -17.36 Na₂O – 16.67 Al₂O₃ – 10.74 ZnF₂ – R Ln (where R= 0.0, 0.1, 0.3 and 0.5 mol % and Ln = Pr³⁺ and Nd³⁺). The absorption spectra of doped ZFBP glasses have been recorded at room temperature. Eight absorption bands have been observed from the ground state ³H₄ to excited states ³F_2,³F_3,³F_4,¹G_4, ¹D₂, ³P₀, ³P₁ and ³P₂ in Pr³⁺ doped ZFBP glasses and twelve absorption bands from the ground state ⁴I_9/2 to excited states ⁴F_3/2, ⁴F_5/2, ⁴F_7/2, ⁴S_3/2, ⁴F_9/2, ²H_11/2, ⁴G_5/2, ⁴G_7/2, ⁴G_9/2, ²G_9/2, ⁴G_11/2, and ²P_1/2 in the case of Nd³⁺ doped ZFBP glasses. From these spectral data various energy interaction parameters like Slater-Condon parameter F_k (k=2, 4, 6), Lande´ parameter ξ_4f and Racah parameters E^k (k=1,2,3) have been computed. Nephelauxetic ratio (') and bonding parameters (b^1/2) have also been computed from these parameters to study the nature of bonding in doped glasses. The intensities of the f-f transitions in the absorption spectra have been analyzed by the application of the Judd-Ofelt theory. J-O parameters (Ω_λ) have been computed. Ω_λ parameters of ZFBP glasses have been compared with those of similar glasses to infer the nature of bonding in these glasses.

Page(s): 65-74

Effects of erbium-doping depth in cladding on the performance of dispersion compensating optical fibre amplifier

Sat, 29 Jan 2005 22:58:59 GMT

Title: Effects of erbium-doping depth in cladding on the performance of dispersion compensating optical fibre amplifier

Authors: Watekar, Pramod R; Goswami, M L N; Biswas, J C; Acharya, H N

Abstract: The theoretical studies regarding change of the erbium-doping depth in cladding from the surface of the core on the performance of the erbium-doped dispersion compensating optical fibre (EDDCF) have been reported. We have also calculated the limits of the detune factor for which the performance of the detuned-EDDCF can be brought equivalent to the performance that would have been obtained with the designed value. This study is useful for deciding the limits of the doping-depth during fabrication of the EDDCF.

Page(s): 17-23

Spectroscopic and thermal studies of zinc/cadmium halide doped silver phosphate glasses

Sat, 29 Jan 2005 22:58:59 GMT

Title: Spectroscopic and thermal studies of zinc/cadmium halide doped silver phosphate glasses

Authors: Das, S S; Baranwal, B P; Gupta, C P; Singh, Punita

Abstract: A number of samples of silver phosphate glasses doped with 1%, 5%, 10% and 20% zinc and cadmium halides were prepared. Control samples of undoped silver phosphate glasses were also prepared. These glasses were characterized by X-ray diffraction, IR spectra, ion transport, and DSC studies. The T_g values obtained from DSC curves were found to increase with increasing concentration of the dopants (Zn/CdX₂) where X= Cl, Br, I in all the cases. The T_g and the conductivity values of all the samples of silver phosphate glasses show the following trend: T_g (CdX₂) > T_g (ZnX₂); X = Cl or Br or I; T_g ( MCl₂) > T_g (MBr₂) > T_g (MI₂); M = Cd or Zn; σ (MI₂) > σ (MBr₂) > σ (MCl₂); M = Cd or Zn. These results have been discussed and explained on the basis of changes in the structure of the glass matrix by the addition of the halide ions of different sizes, IR spectra and ion transport studies.

Page(s): 58-64

Silica-on-silicon based 1N optical splitter: Design, fabrication and characterization

Sat, 29 Jan 2005 22:58:59 GMT

Title: Silica-on-silicon based 1N optical splitter: Design, fabrication and characterization

Authors: Baby, Aji; Dhanavantri, C; Pachauri, J P; Johri, S; Kumar, Pawan; Singh, B R

Abstract: The present paper deals with the design, fabrication technology and performance of silica-on-silicon based 14 and 18 optical power splitter. The basic waveguide structure with S-bends and Y-junctions have been used for the splitter design using BPM software. The optimized process parameters related to choice of metal masking layer, chemistry used for deep dry etching of core layer, dependence of etch process parameters on anisotropy and sidewall smoothness, dicing and fibre alignment are presented. An indigenously built ECR/RIE system especially for deep dry etching of silica layer is also described. The results on splitting insertion loss and uniformity maximum across the channel measured on 14 and 18 splitters are presented.

Page(s): 12-16