Channel-selective wavelength conversion and tuning in periodically poled Ti:LiNbO3 waveguides

Abstract

All-optical wavelength-selective single- and dual-channel wavelength conversion and tuning has been demonstrated in a periodically poled Ti:LiNbO(3) waveguide that has two second-harmonic phase-matching peaks by cascaded sum and difference frequency generation (cSFG/DFG). The wavelength conversion efficiency was measured to be -7 dB with coupled pump power of 233 mW.

Photonic Circuits for Generating Modal, Spectral, and Polarization Entanglement

“…The use of lithium niobate photonic circuits has a number of merits: 1) the properties of the material are well-understood since it has low loss and has long been the basis of integrated-optics technology [33], [34,Chap. 8]; 2) the material can easily be periodically poled [35,36] for the purpose of phase matching parametric interactions. And, as we show in this paper: 3) circuit elements such as mode-separation components can readily be designed for two-mode waveguides; and 4) the generation, separation, and processing of entangled photons can all be accommodated on a single chip.…”

Experimental realization of 40 Gbit/s single-to-single and single-to-dual channel wavelength conversions in LiNbO3 waveguides with two-pump configuration

“…They fulfill the requirements of an ideal wavelength converter, such as ultra-fast response for highspeed wavelength conversion, complete transparency and independence of bit rate and data format, negligible spontaneous emission noise, large conversion bandwidth, high conversion efficiency, no intrinsic frequency chirp and low crosstalk, etc. Three approaches, called direct difference-frequency generation (DFG) [2][3][4], cascaded second-harmonic generation and difference-frequency generation (cSHG/DFG) [4][5][6][7][8][9][10][11][12][13], and cascaded sum-and difference-frequency generation (cSFG/DFG) [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] have been proposed to perform the wavelength conversion within the 1.5-mm band, respectively. In the direct DFG-based wavelength conversion [2][3][4], it is difficult to simultaneously launch the pump in the 0.77-mm band and the signal in the 1.5-mm band into the waveguide.…”

“…In the direct DFG-based wavelength conversion [2][3][4], it is difficult to simultaneously launch the pump in the 0.77-mm band and the signal in the 1.5-mm band into the waveguide. This can be solved by using cSHG/DFG [4][5][6][7][8][9][10][11][12][13] or cSFG/DFG [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], during which all the incident waves are within the 1.5-mm band. In the cSHG/DFG processes [4][5][6][7][8][9][10], one pump wave in the 1.5-mm band is used to yield a frequency-doubled wave in the 0.77-mm band which simultaneously interacts with the 1.5-mm band signal wave to generate an idler wave in the 1.5-mm band.…”

“…In order to achieve optically tunable wavelength conversion, which is required to enhance the flexibility of future network systems, cSFG/ DFG employing two pumps is proposed and demonstrated by Min Y. H. [16], Yamawaku J. [17], Lee Y. L. [18,19], and Yu S. [20], respectively. In their schemes, one pump (pump1) and the signal, both within the 1.5-mm band, generate the sum-frequency wave in the 0.77-mm band.…”

“…Noting that most previous cSFG/DFG schemes employed continuous wave (CW) signals [18][19][20][21][22][23] or operated at relatively low speed [16,17], it did not take full advantage of the ultra-fast nonlinear response characteristic of the PPLN waveguide. Moreover, the amplified spontaneous emission (ASE) noise was strong making the wavelength down-and up-conversions difficult to be simultaneously observed in the experiments [16][17][18][19]21,24]. In addition, although the two kinds of cSFG/DFG schemes above have been demonstrated respectively, their combination, i.e., simultaneous observation of two nonlinear cSFG/DFG interactions, however, has not been reported before.…”