We report the first demonstration of group delay tuning with stimulated Raman scattering-induced dispersion in a hydrogen-filled hollow-core optical fiber.A pump laser induces a sharp refractive index change near the ...We report the first demonstration of group delay tuning with stimulated Raman scattering-induced dispersion in a hydrogen-filled hollow-core optical fiber.A pump laser induces a sharp refractive index change near the S0(0)Raman transition of hydrogen molecules,enabling the control of the group velocity of signal pulses around the Stokes wavelength.Experiments with an 80-m-long hollow-core fiber filled with 2.5 bar hydrogen achieved continuous tuning of the pulse delay up to 1.42 ns by varying the Raman amplification from 0 to 10 dB.The tunable pulse delay is realized by changing the pump power as well as the hydrogen pressure.This work provides a new technique for controlling the pulse propagation in optical fibers with high flexibility.展开更多
Gain saturation is a significant phenomenon of fiber Raman amplifiers（FRAs）.Gain figures versus signal power are well explained.For the small signal,the coupled ordinary differential equations are used,and for the l...Gain saturation is a significant phenomenon of fiber Raman amplifiers（FRAs）.Gain figures versus signal power are well explained.For the small signal,the coupled ordinary differential equations are used,and for the large signal,the Raman gain coefficient is modified.It is shown that the saturation power of FRAs decreases with the pump power,and gain saturation is easier to occur in the forward pump scheme than in the backward pump scheme.These phenomena are well explained by the stimulated Brillouin scattering （SBS） effect.This research provides a guide to the fabrication of practical FRAs.展开更多
基金This work was supported by the Hong Kong SAR government(GRF grant PolyU 152210/18E)the National Natural Science Foundation of China(Nos.61827820 and 61535004)the Hong Kong Polytechnic University(Nos.1-ZVG4 and 4-BCD1).
文摘We report the first demonstration of group delay tuning with stimulated Raman scattering-induced dispersion in a hydrogen-filled hollow-core optical fiber.A pump laser induces a sharp refractive index change near the S0(0)Raman transition of hydrogen molecules,enabling the control of the group velocity of signal pulses around the Stokes wavelength.Experiments with an 80-m-long hollow-core fiber filled with 2.5 bar hydrogen achieved continuous tuning of the pulse delay up to 1.42 ns by varying the Raman amplification from 0 to 10 dB.The tunable pulse delay is realized by changing the pump power as well as the hydrogen pressure.This work provides a new technique for controlling the pulse propagation in optical fibers with high flexibility.
基金supported by the Program for New Century Excellent Talents in University under Grant No.NCET-06-0925
文摘Gain saturation is a significant phenomenon of fiber Raman amplifiers（FRAs）.Gain figures versus signal power are well explained.For the small signal,the coupled ordinary differential equations are used,and for the large signal,the Raman gain coefficient is modified.It is shown that the saturation power of FRAs decreases with the pump power,and gain saturation is easier to occur in the forward pump scheme than in the backward pump scheme.These phenomena are well explained by the stimulated Brillouin scattering （SBS） effect.This research provides a guide to the fabrication of practical FRAs.
