Browsing by Author "Lee, RK"

Now showing 1 - 8 of 8

Amplitude-squeezed fiber-Bragg-grating solitons
(2004-02-01)
Lee, RK
;
Lai, Y
;
光電工程研究所
;
Institute of EO Enginerring
Quantum fluctuations of optical fiber-Bragg-grating solitons are investigated numerically by the back-propagation method. It is found that the band-gap effects of the grating act as a nonlinear filter and cause the soliton to be amplitude squeezed. The squeezing ratio saturates after a certain grating length and the optimal squeezing ratio occurs when the pulse energy is slightly above the fundamental soliton energy.
Fluorescence squeezing spectra near a photonic bandgap
(2004-08-01)
Lee, RK
;
Lai, YC
;
光電工程學系
;
Department of Photonics
The fluorescence intensity and quadrature spectra from a two-level atom embedded in a photonic bandgap crystal and resonantly driven by a classical pump light are calculated. The non-Markovian nature of the problem caused by the non-uniform distribution of the photonic density of states is handled by linearizing the generalized optical Bloch equations with the Liouville operator expansion. Unlike the case in free space, we find that the bandgap effects will not only modify the fluorescence spectral shape but also cause squeezing in the in-phase quadrature spectra.
Generation of photon-number-entangled soliton pairs through interactions
(2005-01-01)
Lee, RK
;
Lai, Y
;
Malomed, BA
;
光電工程學系
;
光電工程研究所
Two simple schemes for generating macroscopic (many-photon) continuous-variable entangled states by means of continuous interactions (rather than collisions) between solitons in optical fibers are proposed. First, quantum fluctuations around two time-separated single-component temporal solitons are considered. Almost perfect correlation between the photon-number fluctuations can be achieved after passing a certain distance, with a suitable initial separation between the solitons. The photon-number correlation can also be achieved in a pair of vectorial solitons with two polarization components. In the latter case, the photon-number-entangled pulses can be easily separated by a polarization beam splitter. These results offer possibilities to produce entangled sources for quantum communication and computation.
Photon-number fluctuation and correlation of bound soliton pairs in mode-locked fiber lasers
(2005-11-15)
Lee, RK
;
Lai, YC
;
Malomed, BA
;
光電工程學系
;
Department of Photonics
Quantum photon-number fluctuation and correlation of bound soliton pairs in mode-locked fiber lasers are studied on the basis of the complex Ginzburg-Landau equation model. We find that, depending on their phase difference, the total photon-number noise of the bound soliton pair can be larger or smaller than that of a single soliton, and the two solitons in the soliton pair have a corresponding positive or negative photon-number correlation. It is predicted for the first time to our knowledge that out-of-phase soliton pairs can exhibit less noise as a result of negative correlation. (c) 2005 Optical Society of America.
Quantum correlations in bound-soliton pairs and trains in fiber lasers
(2004-12-01)
Lee, RK
;
Lai, Y
;
Malomed, BA
;
光電工程學系
;
光電工程研究所
Quantum correlations in pairs and arrays (trains) of bound solitons modeled by the complex Ginzburg-Landau equation (CGLE) are calculated numerically, on the basis of linearized equations for quantum fluctuations. We find strong correlations between the bound solitons, even though the system is dissipative. Some degree of the correlation between the photon-number fluctuations of stable bound soliton pairs and trains is attained and saturates after passing a certain distance. The saturation of the photon-number correlations is explained by the action of nonconservative terms in the CGLE. Photon-number-correlated bound soliton trains offer possibilities to produce multipartite entangled sources for quantum communication and computation.
Quantum correlations in soliton collisions
(2005-03-01)
Lee, RK
;
Lai, YC
;
Kivshar, YS
;
光電工程學系
;
光電工程研究所
We study quantum correlations and quantum noise in soliton collisions described by a general two-soliton solution of the nonlinear Schrodinger equation by using the back-propagation method. Our results include the standard case of a sech-shaped initial pulse analyzed earlier. We reveal that double-hump initial pulses can get more squeezed and the squeezing ratio enhancement is due to the long collision period in which the pulses are more stationary. These results offer promising possibilities of using higher-order solitons to generate strongly squeezed states for the quantum information process and quantum computation.
Quantum-noise properties of matter-wave gap solitons
(2005-09-01)
Lee, RK
;
Ostrovskaya, EA
;
Kivshar, YS
;
Lai, Y
;
光電工程學系
We study quantum-noise squeezing and quantum correlations of gap solitons in a Bose-Einstein condensate loaded into a one-dimensional optical lattice. By employing a linearized quantum theory we find that quantum-noise squeezing of gap solitons, produced during their evolution, is enhanced compared with the atomic solitons in a lattice-free case due to intrasoliton structure of quantum correlations induced by the Bragg scattering in the periodic potential. We also show that nonlinear interaction of gap solitons in dynamically stable bound states can produce strong atom-number correlation between the soliton pairs.
Resonance fluorescence spectrum near photonic bandgap
(2003)
Lee, RK
;
Lai, Y
;
光電工程學系
;
Department of Photonics
We theoretically calculate the resonance fluorescence spectrum from a two-level atom which is embedded in a photonic bandgap crystal and is resonantly driven by a classical pump light. Non-Markovian noises caused by the non-uniform distribution of photon density states near the photonic bandgap, are taken into account by a new approach which linearizes the optical Bloch equations by using the Liouville operator expansion. These linearized equations can be solved directly in the Fourier domain to obtain the correlation functions of the atomic operators and then the fluorescence spectrum from the atom. We find that if the atomic energy level is far from the bandgap, fluorescence spectra with Mollow triplets are observed. When the atomic energy level is near the bandgrap, the relative magnitude and the number of the fluorescence peaks are found to be varied accordinu to the wavelength offset.