Proposal of optically tunable and reconfigurable multi-channel bandstop filter using sum-frequency generation in a PPLN waveguide

Investigation of high-polarization-isolation optical parametric amplifier using a periodically poled lithium niobate waveguide

“…Lithium niobate has become an important optical material because of its numerous advantages, such as high electro-optic coefficient, high second-order nonlinear coefficient and can be fabricated into waveguide et al [2][3][4] . Therefore, it has been widely used in electro-optic modulating [5][6][7] , signal processing [8][9][10][11][12][13][14] and electromagnetic field sensing [15][16][17][18] . Particularly, the optical parametric amplifiers (OPAs) based on second-order optical nonlinear effects have attracted great attention, owing to the advantages of all-optical amplifying, low noise and easy to integrate [19][20][21] .…”

“…Particularly, the optical parametric amplifiers (OPAs) based on second-order optical nonlinear effects have attracted great attention, owing to the advantages of all-optical amplifying, low noise and easy to integrate [19][20][21] . As a ferroelectric material, the second-order polarizability of lithium niobate can be conveniently reversed under strong electric field to produce the periodically poled lithium niobate (PPLN) waveguide, which is usually employed to compensate the phase mismatch in second-order nonlinear optical parametric process [8][9][10][11][12][13][14][19][20][21] . The corresponding phase matching technology is called quasi-phase matching (QPM).…”