Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Broadband wavelength converter based on segmented quasi-phase matched grating

Tao Liu, Baogang Li

Published Aug 24, 2010• 1 citation
Publisher

Abstract

Broadband wavelength converters based on difference frequency generation (DFG), single-pass and double-pass cascaded second harmonic generation and difference frequency generation (SHG+DFG), single-pass and double-pass cascaded sum and difference frequency generation (SFG+DFG) are fulfilled by utilizing segmented grating structure in lithium niobate waveguide. Under the small-signal approximation, the effects of the waveguide length and the response flatness on DFG-based wavelength conversion are investigated by use of matrix operator, and then a feasible scheme to enhance the bandwidth and stability of signal and pump wave is proposed. For single-pass/double-pass SHG+DFG wavelength conversion scheme and single-pass/double-pass SFG+DFG wavelength conversion scheme, the effect of segmented grating structure on conversion bandwidth is studied theoretically and numerically, the results show that the signal conversion bandwidth can be broadened by optimizing the aperiodic grating. Moreover, the influence of "balance condition" on double-pass SFG+DFG-based wavelength conversion is analyzed, one can achieve enhanced conversion efficiency and conversion bandwidth by adjusting the power and wavelengths of pump sources according to the "balance condition". In the end, a reasonable suggestion is presented to achieve broadband wavelength conversion under different requirements.

DOI
10.1117/12.885201

Related papers

Flat broadband wavelength conversion based on cascaded second-harmonic generation and difference frequency generation in segmented quasi-phase matched gratings

Tao Liu, Yulin Qi, Linlin Che +3 more

Bandwidth enhancement and response flattening of wavelength conversion based on single-pass and double-pass cascaded second harmonic generation and difference frequency generation were investigated in segmented quasi-phase matched (QPM) gratings. It is shown that the signal and pump bandwidths are both efficiently widened by increasing the segment number of the QPM grating and optimising the poling period of each segment. The ripple on the matching response is also very small. The conversion bandwidth in a 3-cm-long three-segment waveguide reaches 150–160 nm, which is over the whole conventional band and long-wavelength band. Larger signal bandwidth can be obtained with a little response flatness penalty and conversion efficiency penalty, which can be compensated by increasing the input pump power. Compared with a sinusoidally chirped optical superlattice device, a wavelength converter based on the segmented gratings has higher conversion efficiency, broader bandwidth and better pump-wavelength tolerance, and is easier to fabricate in practice.

Journal of Modern Optics•Feb 2, 2012•6 citations

Flattop Broadband Wavelength Conversion Based on Cascaded Second-Harmonic Generation and Difference Frequency Generation in Step-Segmented Quasi-Phase Matched Gratings

Hai Dong Wu, Jin Song Guo, Yun Wen Wu +1 more

Bandwidth enhancement and response flattening of wavelength conversion based on single-pass and double-pass cascaded second harmonic generation and difference frequency generation in step-segmented quasi-phase matched (QPM) gratings are investigated. For the same waveguide length, high conversion efficiency, flat response and broad signal bandwidth can be obtained simultaneously by optimizing the poling period of the step-segmented QPM structure. The conversion bandwidths in a 3-cm-long five-step-segmented waveguide are 134 nm for single-pass scheme and 132 nm for the double-pass one, respectively, which are both over the whole conventional band and long-wavelength band. The ripple on the matching response can keeps less than 0.2 dB as well.

Advanced materials research•Jul 1, 2014•0 citations

Flattop broadband wavelength converters based on double-pass cascaded SFG + DFG in quasi-phase matched waveguides

Amirhossein Tehranchi, Raman Kashyap

Wavelength converters based on double-pass quasi-phase matched cascaded sum and difference frequency generation in lossy lithium niobate waveguides with a large pump wavelength difference are numerically evaluated assuming pump wavelength detuning to flatten the response.

IEEE Lasers and Electro-Optics Society Annual Meeting (LEOS)•Oct 1, 2009•0 citations

Comparison of cascaded χ2 wavelength conversions in quasi-phase-matched (QPM) waveguides

Bo Chen, Chang‐Qing Xu

Cascaded second-order nonlinear interaction (&chi(2));based wavelength conversion technique has attracted much attention due to its unique characteristics such as low noise and broadband, which are critical in fiber communication networks. In this report, wavelength conversions based on the newly proposed SFG-DFG (sum frequency generation - difference frequency generation) and conventional SHG-DFG (second harmonic generation - difference frequency generation) are studied and compared both experimentally and theoretically in a LiNbO3 quasi-phase matched (QPM) waveguide. It is shown that the same conversion efficiency can be achieved by employing two pump sources with only half power each (P1, P2) in the SFG-DFG scheme as compared with the SHG-DFG scheme with a single higher power pump beam (P=P1+P2). It is shown that the cascaded SFG-DFG based wavelength conversion has a larger 3-dB pump tolerance bandwidth. The theoretical results are consistent well with the experimental ones. It is found that the pump wavelength difference can be separated by a span as large as 75 nm, while 3-dB signal conversion efficiency is retained in a 45 mm-long device. It is also exhibited that tolerance of temperature for the cascaded SFG-DFG remains the same as that of the cascaded SHG-DFG based devices. The results show that the SFG-DFG wavelength conversion scheme is very attractive for practical applications.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Nov 16, 2004•0 citations

Flattening of cascaded sum- and difference-frequency generation-based wavelength conversion by pump or period detuning

Shiming Gao, Changxi Yang, Xiaosheng Xiao +3 more

We investigate response flatting of cascaded sum- and difference- frequency generation (SFG/DFG)-based wavelength conversion in quasi-phase-matched (QPM) periodically poled lithium niobate waveguides for wavelength division multiplexing optical communication systems. The cascaded SFG/DFG-based configuration shows more robustly combined properties than conventional DFG-based and cascaded second-harmonic generation and DFG (SHG/DFG)-based configurations. The response fluctuation, generated while enhancing the conversion bandwidth, can be efficiently reduced by the method of pump detuning or QPM period detuning.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Nov 24, 2005•0 citations

Response Flattening of Efficient Broadband Wavelength Converters Based on Cascaded Sum and Difference Frequency Generation in Periodically Poled Lithium Niobate Waveguides

Amirhossein Tehranchi, Raman Kashyap

For the single-pass and double-pass wavelength converters based on cascaded sum and difference frequency generation in quasi-phase matched lithium niobate waveguide, we present the criteria for a choice of the waveguide length and the assignment of pump powers to achieve the desired efficiency, ripple and bandwidth with a large pump wavelength difference of 75 nm. It is found that using the double-pass structure with a 95% reflectivity for the sum frequency wave, the mean efficiency is increased at least 5 dB compared to that of the single-pass one with the same length and input pump powers and the bandwidth is large enough to cover the entire conventional telecommunications C-band and long-wavelength L-band. To flatten the excessive response fluctuation of the double-pass scheme, we propose tuning one of the pumps to longer wavelengths incurring a small penalty of a slight reduction in the mean efficiency which can be compensated by increasing the input pump powers. We also show that to achieve the same amount of flatness, double-pass converters have a smaller efficiency penalty compared to the single-pass converters.

IEEE Journal of Quantum Electronics•Aug 24, 2009•7 citations
Broadband wavelength converters based on difference frequency generation (DFG), single-pass and double-pass cascaded second harmonic generation and difference frequency generation (SHG+DFG), single-pass and double-pass cascaded sum and difference frequency generation (SFG+DFG) are fulfilled by utilizing segmented grating structure in lithium niobate waveguide. Under the small-signal approximation, the effects of the waveguide length and the response flatness on DFG-based wavelength conversion are investigated by use of matrix operator, and then a feasible scheme to enhance the bandwidth and stability of signal and pump wave is proposed. For single-pass/double-pass SHG+DFG wavelength conversion scheme and single-pass/double-pass SFG+DFG wavelength conversion scheme, the effect of segmented grating structure on conversion bandwidth is studied theoretically and numerically, the results show that the signal conversion bandwidth can be broadened by optimizing the aperiodic grating. Moreover, the influence of "balance condition" on double-pass SFG+DFG-based wavelength conversion is analyzed, one can achieve enhanced conversion efficiency and conversion bandwidth by adjusting the power and wavelengths of pump sources according to the "balance condition". In the end, a reasonable suggestion is presented to achieve broadband wavelength conversion under different requirements.
Bandwidth enhancement and response flattening of wavelength conversion based on single-pass and double-pass cascaded second harmonic generation and difference frequency generation were investigated in segmented quasi-phase matched (QPM) gratings. It is shown that the signal and pump bandwidths are both efficiently widened by increasing the segment number of the QPM grating and optimising the poling period of each segment. The ripple on the matching response is also very small. The conversion bandwidth in a 3-cm-long three-segment waveguide reaches 150–160 nm, which is over the whole conventional band and long-wavelength band. Larger signal bandwidth can be obtained with a little response flatness penalty and conversion efficiency penalty, which can be compensated by increasing the input pump power. Compared with a sinusoidally chirped optical superlattice device, a wavelength converter based on the segmented gratings has higher conversion efficiency, broader bandwidth and better pump-wavelength tolerance, and is easier to fabricate in practice.
Bandwidth enhancement and response flattening of wavelength conversion based on single-pass and double-pass cascaded second harmonic generation and difference frequency generation in step-segmented quasi-phase matched (QPM) gratings are investigated. For the same waveguide length, high conversion efficiency, flat response and broad signal bandwidth can be obtained simultaneously by optimizing the poling period of the step-segmented QPM structure. The conversion bandwidths in a 3-cm-long five-step-segmented waveguide are 134 nm for single-pass scheme and 132 nm for the double-pass one, respectively, which are both over the whole conventional band and long-wavelength band. The ripple on the matching response can keeps less than 0.2 dB as well.
Cascaded second-order nonlinear interaction (&chi(2));based wavelength conversion technique has attracted much attention due to its unique characteristics such as low noise and broadband, which are critical in fiber communication networks. In this report, wavelength conversions based on the newly proposed SFG-DFG (sum frequency generation - difference frequency generation) and conventional SHG-DFG (second harmonic generation - difference frequency generation) are studied and compared both experimentally and theoretically in a LiNbO3 quasi-phase matched (QPM) waveguide. It is shown that the same conversion efficiency can be achieved by employing two pump sources with only half power each (P1, P2) in the SFG-DFG scheme as compared with the SHG-DFG scheme with a single higher power pump beam (P=P1+P2). It is shown that the cascaded SFG-DFG based wavelength conversion has a larger 3-dB pump tolerance bandwidth. The theoretical results are consistent well with the experimental ones. It is found that the pump wavelength difference can be separated by a span as large as 75 nm, while 3-dB signal conversion efficiency is retained in a 45 mm-long device. It is also exhibited that tolerance of temperature for the cascaded SFG-DFG remains the same as that of the cascaded SHG-DFG based devices. The results show that the SFG-DFG wavelength conversion scheme is very attractive for practical applications.
We investigate response flatting of cascaded sum- and difference- frequency generation (SFG/DFG)-based wavelength conversion in quasi-phase-matched (QPM) periodically poled lithium niobate waveguides for wavelength division multiplexing optical communication systems. The cascaded SFG/DFG-based configuration shows more robustly combined properties than conventional DFG-based and cascaded second-harmonic generation and DFG (SHG/DFG)-based configurations. The response fluctuation, generated while enhancing the conversion bandwidth, can be efficiently reduced by the method of pump detuning or QPM period detuning.
For the single-pass and double-pass wavelength converters based on cascaded sum and difference frequency generation in quasi-phase matched lithium niobate waveguide, we present the criteria for a choice of the waveguide length and the assignment of pump powers to achieve the desired efficiency, ripple and bandwidth with a large pump wavelength difference of 75 nm. It is found that using the double-pass structure with a 95% reflectivity for the sum frequency wave, the mean efficiency is increased at least 5 dB compared to that of the single-pass one with the same length and input pump powers and the bandwidth is large enough to cover the entire conventional telecommunications C-band and long-wavelength L-band. To flatten the excessive response fluctuation of the double-pass scheme, we propose tuning one of the pumps to longer wavelengths incurring a small penalty of a slight reduction in the mean efficiency which can be compensated by increasing the input pump powers. We also show that to achieve the same amount of flatness, double-pass converters have a smaller efficiency penalty compared to the single-pass converters.