Quoc Khanh Ngo - Academia.edu (original) (raw)
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Papers by Quoc Khanh Ngo
Nonlinear Analysis: Theory, Methods & Applications, 2010
In this paper, using nonsmooth critical point theory, we study the existence of multiple solution... more In this paper, using nonsmooth critical point theory, we study the existence of multiple solutions of the following class of problems: −div (|x| −ap |∇u| p−2 ∇u) ∈ λ|x| −(a+1)p+c [f − (u), f + (u)], x ∈ Ω, u = 0, x ∈ ∂Ω, where a, c, λ and f − , f + satisfy certain conditions.
In this paper, some integral inequalities are presented by analytic approach. An open question wi... more In this paper, some integral inequalities are presented by analytic approach. An open question will be proposed later on.
All polarization maintaining fiber Sagnac interferometers with linearly birefringence are propose... more All polarization maintaining fiber Sagnac interferometers with linearly birefringence are proposed for the construction of stable comb filters. The transfer functions of the filters can be determined if stress-induced birefringence fiber is used because its birefringence is more or less independent of wavelength. The transfer function of the simplest filter, which acts as a comb filter, with only one polarization mode-coupling point is obtained. Several filters have been realized; they exhibit channel isolation of about 22 dB and can be used as frequency selectors in multi-wavelength fiber lasers. We also discuss the potential applications of the proposed filter that include add-drop multiplexers in wavelength division multiplexing (WDM) systems, gain flattening in fiber amplifiers, and switches/modulators.
Nonlinear Analysis: Theory, Methods & Applications, 2010
In this paper, using nonsmooth critical point theory, we study the existence of multiple solution... more In this paper, using nonsmooth critical point theory, we study the existence of multiple solutions of the following class of problems: −div (|x| −ap |∇u| p−2 ∇u) ∈ λ|x| −(a+1)p+c [f − (u), f + (u)], x ∈ Ω, u = 0, x ∈ ∂Ω, where a, c, λ and f − , f + satisfy certain conditions.
In this paper, some integral inequalities are presented by analytic approach. An open question wi... more In this paper, some integral inequalities are presented by analytic approach. An open question will be proposed later on.
All polarization maintaining fiber Sagnac interferometers with linearly birefringence are propose... more All polarization maintaining fiber Sagnac interferometers with linearly birefringence are proposed for the construction of stable comb filters. The transfer functions of the filters can be determined if stress-induced birefringence fiber is used because its birefringence is more or less independent of wavelength. The transfer function of the simplest filter, which acts as a comb filter, with only one polarization mode-coupling point is obtained. Several filters have been realized; they exhibit channel isolation of about 22 dB and can be used as frequency selectors in multi-wavelength fiber lasers. We also discuss the potential applications of the proposed filter that include add-drop multiplexers in wavelength division multiplexing (WDM) systems, gain flattening in fiber amplifiers, and switches/modulators.