Patent ID: 7082234

Claim:
A wavelength division multiplexing device, comprising: a first optical circulator having a first plurality of ports; and a Fiber Bragg Grating (FBG) connected to one of the first plurality of ports of the first optical circulator to reflect or transmit some of wavelength channels of an optical signal input to the first optical circulator; wherein the FBG has a phase-sampled grating with a coupling coefficient, and in which a refractive index of an optical fiber core is modulated by a predetermined chirp in a grating period and a predetermined chirp in a sampling period, and the chirps in the grating period and the sampling period are set to allow dispersion values of all wavelength channels, which are reflected in the FBG, to have a linear function relationship with wavelengths; wherein the coupling coefficient is expressed by the following equation: κ m =πΔn 1 F m /λ B where Δn 1 is a modulation amplitude constant, λ B is a Bragg wavelength, and F m is a Fourier coefficient that is used to express a phase sampling function φ(z) in terms of a refractive index of the FBG using the following equation, n ⁡ ( z ) = ⁢ n 0 + Δ ⁢ ⁢ n 1 ⁢ Re ⁢ { exp ⁡ [ i ⁡ ( 2 ⁢ β 0 ⁢ z + ϕ ⁡ ( z ) ) ] } = ⁢ n 0 + Δ ⁢ ⁢ n 1 ⁢ Re ⁢ { ∑ m ⁢ F m ⁢ exp ⁡ [ 2 ⁢ i ⁡ ( β 0 + m ⁢ ⁢ β s ) ⁢ z ] } wherein n 0 is an average refractive index, β 0 =π/Λ 0 , β s =π/Λ s , Λ 0 is an average grating period and Λ s is a period of a sampling function.