Cristian Parra Alvial Elo 352: Comunicaciones por fibra óptica Profesor: Ricardo Olivares Fecha: 31/10/2017 Problema 2.17 A 1.55-µm continuous-wave signal with 6-dBm power is launched into a fiber with 5 0-µm2 effective mode area. After what fiber length would the nonlinear phase shift induced by SPM become 2π 2π? Assume ¯n2 = 2.6 × 10−20 m2/W and neglect neglect fiber losses.
λ = 1, 5 5 5 μ μ = 66 = 50 50=0,μ 0 039 039 μ ̅ = 2,6 ⋅ 10− ϕ = ⋅ ⋅ = + ⋅ ⋅ = = 7878 ⋅ 10 = 764.29
Intensidad corresponde a: Con
= 0, se tiene que el largo es:
Problema 2.18 Calculate the threshold power for stimulated Brillouin scattering for a 50-km fiber link operating at 1.3 µm and having a loss of 0.5 dB/km. How much does the threshold power change if the operating wavelength is changed to 1.55 µm, w here the fiber loss is only 0.2 dB/km? Assume that Aeff = 50 µm2 and gB = 5×10−11 m/W at both wavelengths. wavelengths.
− = 50 50 , = 50 50 , = 5⋅5 ⋅ 10
= 1,3 , = 0,5 [] = 0,1151[] ] = 0,046[] = 1,55, = 0,2 [ = 1− = 8,66 = 19,5596 20 = ⋅⋅ ∴ = 2,309 = 1,0204 , con
Umbral Brillouin:
Se tiene como resultado 2 potencias distintas:
Problema 2.19 Calculate the power launched into a 40 -km-long single-mode fiber for which the SPM-induced nonlinear phase shift becomes 180◦. Assume λ = 1.55 µm, Aeff = 40 µm2, α = 0.2 dB/km, and ¯n2 = 2.6×10−20 m2/W
= 40 180°, = 1,55, = 40, = 0,2 [ ] 1 −´ = ´ ⋅ (1 ), ´[k] ] ´ = 0,046051[k = 18,273 ϕ = ⋅ ⋅ = + ⋅ ⋅ = = 0 = = 1,63124⋅ 10 [] = ⋅ = 0,06524 = 65,24 Luego el largo efectivo es:
Con
,
, con
La potencia está dada por
, finalmente se obtiene la intensidad
Problema 2.20 Find the maximum frequency shift occurring because of t he SPM-induced chirp imposed on a Gaussian pulse of 20-ps width (FWHM) and 5-mW peak power after it has propagated 100 km. Use the fiber parameters of the preceding problem but assume α = 0.
