All-optical wavelength conversion and tuning by the cascaded sum- and difference frequency generation (cSFG/DFG) in a temperature gradient controlled Ti:PPLN channel waveguide

Abstract

All-optical single and multiple wavelength conversion and tuning by the cascaded sum- and difference frequency generation (cSFG/DFG) have been demonstrated in a temperature gradient controlled periodically poled Ti:LiNbO3 (Ti:PPLN) channel waveguide. Up to 4 channels of wavelength division multiplexed (WDM) signals which have 100 GHz channel spacing were simultaneously wavelength converted at a 16.8 degrees C temperature difference between both end faces in a Ti:PPLN waveguide. The 3 dB signal conversion bandwidth was measured to be as broad as 48 nm at single channel conversion. The maximum wavelength conversion efficiency and optical signal to noise ratio of wavelength converted channel were approximately -16 dB and -20 dB at a total pump power level of 810 mW.

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.…”

Tunable wavelength converters of picosecond pulses based on periodically poled LiNbO3 waveguides

“…The most recent wavelength conversion techniques include the use of cross-gain modulation (XGM) [2], cross-phase modulation (XPM) [3], cross-absorption modulation (XAM) [4], and four-wave mixing (FWM) [5] in semiconductor optical amplifiers (SOAs) as well as second-order nonlinearities in passive optical waveguides [6][7][8][9][10][11][12][13][14][15][16][17][18]. Among these conversion schemes, wavelength conversion based on second-order nonlinearities in periodically poled LiNbO 3 (PPLN) waveguides has shown distinct advantages [6][7][8][9][10][11][12][13][14][15][16][17][18]. Besides the function of switching the information carried by input signal, PPLN-based wavelength conversion has other promising merits such as ultra-fast response, convenience for tunable operation, negligible spontaneous emission noise, and no intrinsic frequency chirp.…”

“…Several second-order nonlinearities in quasi-phase matching (QPM) PPLN waveguides have attracted increasing attention in recent years, including direct difference-frequency generation (DFG) [9,10], cascaded second-harmonic generation and difference-frequency generation (cSHG/DFG) [10][11][12][13], and cascaded sumand difference-frequency generation (cSFG/DFG) [14][15][16][17][18]. However, most previous researches suffered due to the great limitation on operating at the continuous-wave (CW) situation [9][10][11][12][13][14][15][16]. Although pulsed signals were employed in some experiments [17,18], amplified spontaneous emission (ASE) noise originating from the erbium-doped fiber amplifier (EDFA) was induced in the experimental systems.…”

Experimental investigation on a software synchronous optical sampling technique based on periodically poled lithium niobate

“…Due to their extremely short response times, nonlinear processes, such as second harmonic generation (SHG) and sum frequency generation (SFG), based on second-order nonlinear interaction in PPLN have been widely utilized in several domains, including all-optical wavelength conversion [6,7] , all-optical format conversion [8] , and optical sampling systems [9−11] , among others.…”