Quantum dot gain spectra based on harmonic oscillator model are calculated including and excluding excitons. The effects of non-equilibrium distributions are considered at low temperatures. The variations of threshold...Quantum dot gain spectra based on harmonic oscillator model are calculated including and excluding excitons. The effects of non-equilibrium distributions are considered at low temperatures. The variations of threshold current density in a wide temperature range are analyzed and the negative characteristic temperature and oscillatory characteristic temperature appearing in that temperature range are discussed. Also,the improvement of quantum dot lasers＇ performance is investigated through vertical stacking and p-type doping and the optimal dot density, which corresponds to minimal threshold current density,is calculated.展开更多
We use four-level atomic system and control the wave propagation via forbidden decay rate. The Raman gain process becomes dominant on electromagnetically induced transparency (EIT) medium by increasing the forbidden d...We use four-level atomic system and control the wave propagation via forbidden decay rate. The Raman gain process becomes dominant on electromagnetically induced transparency (EIT) medium by increasing the forbidden decay rate via increasing the number of atoms [G.S. Agarwal and T.N. Dey, Phys. Rev. A 74 (2005) 043805 and K. Harada, T. Kanbashi, and M. Mitsunaga, Phys. Rev. A 73 (2006) 013803]. The behavior of wave propagation is dramatically changed from normal (subluminal) to anomalous (superluminal) dispersion by increasing the forbidden decay rate. The system can also give a control over the group velocity of the light propagating through the medium via Kerr field.展开更多
We theoretically and experimentally show the impact of the ratio between the signal and idler generated from the PIA part on the gain characteristics in the continuous wave (CW) pump non-degenerate cascaded phase-sens...We theoretically and experimentally show the impact of the ratio between the signal and idler generated from the PIA part on the gain characteristics in the continuous wave (CW) pump non-degenerate cascaded phase-sensitive fiber optical parametric amplifier (PS-FOPA). The results show that the length of highly nonlinear fiber (HNLF) used for generating the idler can cause the variation of power ratio between the idler and signal, which significantly affects the gain characteristics of the PS-FOPA under the small signal gain condition. To obtain high gain, it is better to choose long HNLF to generate idler. In our experiment, 5.5 dB gain and 18 nm bandwidth (on/off gain>10 dBm) in PS-FOPA can be achieved when 300 m-long HNLF instead of 200 m-long HNLF is used in PIA.展开更多
文摘Quantum dot gain spectra based on harmonic oscillator model are calculated including and excluding excitons. The effects of non-equilibrium distributions are considered at low temperatures. The variations of threshold current density in a wide temperature range are analyzed and the negative characteristic temperature and oscillatory characteristic temperature appearing in that temperature range are discussed. Also,the improvement of quantum dot lasers＇ performance is investigated through vertical stacking and p-type doping and the optimal dot density, which corresponds to minimal threshold current density,is calculated.
文摘We use four-level atomic system and control the wave propagation via forbidden decay rate. The Raman gain process becomes dominant on electromagnetically induced transparency (EIT) medium by increasing the forbidden decay rate via increasing the number of atoms [G.S. Agarwal and T.N. Dey, Phys. Rev. A 74 (2005) 043805 and K. Harada, T. Kanbashi, and M. Mitsunaga, Phys. Rev. A 73 (2006) 013803]. The behavior of wave propagation is dramatically changed from normal (subluminal) to anomalous (superluminal) dispersion by increasing the forbidden decay rate. The system can also give a control over the group velocity of the light propagating through the medium via Kerr field.
基金supported by the National Basic Research Program of China (Nos.2010CB327605 and 2010CB328300)the Specialized Research Fund for the Young Scholars Program of Beijing University of Posts and Telecommunications (Nos.2011RC0309 and 2011RC008)
文摘We theoretically and experimentally show the impact of the ratio between the signal and idler generated from the PIA part on the gain characteristics in the continuous wave (CW) pump non-degenerate cascaded phase-sensitive fiber optical parametric amplifier (PS-FOPA). The results show that the length of highly nonlinear fiber (HNLF) used for generating the idler can cause the variation of power ratio between the idler and signal, which significantly affects the gain characteristics of the PS-FOPA under the small signal gain condition. To obtain high gain, it is better to choose long HNLF to generate idler. In our experiment, 5.5 dB gain and 18 nm bandwidth (on/off gain>10 dBm) in PS-FOPA can be achieved when 300 m-long HNLF instead of 200 m-long HNLF is used in PIA.
