Optics Express

Parametric wavelength conversion with bidirectional utilization of a multiple QPM device

Masaki Asobe, Saroeun Punhavan, Kato Masato, Takeshi Umeki, Koji Enbutsu, Takushi Kazama, Ryoichi Kasahara

Published Jun 22, 2021• 5 citations

Abstract

A configuration for wavelength conversion and optical amplification by parametric interaction using a nonlinear optical device is proposed. It enables pump generation through second harmonic generation (SHG), difference frequency generation (DFG), and optical parametric amplification (OPA) using a multiple-quasi-phase-matched (M-QPM) LiNbO3 waveguide in a bidirectional manner. Wavelength conversion for the 1.4–1.6 µm band is experimentally demonstrated. In addition, it is demonstrated that the parametric gain band can be changed using various detunings between the pump and QPM wavelengths used for the DFG/OPA process. The proposed method would be useful for enabling high-capacity optical transmission outside the 1550-nm band.

DOI: 10.1364/oe.428868

Related papers

Broadband optical parametric amplification using PPLN waveguide pumped by detuned second harmonic

Masaki Asobe, Daiki Yagi, Yuki Kawabata +4 more

Optical parametric amplification in the range of 1.3–1.8 µm was demonstrated by using a periodically poled LiNbO3 (PPLN) waveguide as a nonlinear medium by varying the detuning of the pump wavelength. A wide range of detuning was enabled by using a multiple-quasi-phase-matched (M-QPM) LiNbO3 waveguide for pump generation through second harmonic generation (SHG) and temperature control of the PPLN waveguide. Broadband optical amplification and wavelength conversion through difference frequency generation (DFG) are considered useful for widening the bandwidth of optical communication.

Optics ExpressMar 2, 202211 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 SPIENov 16, 20040 citations

Parametric optical amplification using a reflective multiple quasi-phase-matched LiNbO 3 waveguide module

Masaki Asobe, Yuki Kawabata, Daiki Yagi +3 more

Optical parametric amplification (OPA) in the S-band with a compact configuration was demonstrated using a reflective multiple quasi-phase-matched (M-QPM) LiNbO 3 waveguide module. The reflective-module-assembled LiNbO 3 waveguide has two QPM peaks and a built-in mirror that reflects only the second harmonic. These features make it possible to perform second harmonic pump generation and OPA under different phase-matching conditions using a single device. The idler light generated in the module retains the phase information from the signal light and is used to evaluate signal quality.

Optics ContinuumJan 31, 20240 citations

Comparison of wavelength conversions based on cascaded second-harmonic generation/difference-frequency generation under continuous-wave and pulsed pumping

Yong Wang, Jorge Fonseca-Campos, Chang-Qing Xu +3 more

The implementation of wavelength conversion around 1.55 μm in quasi-phase-matched (QPM) periodically poled LiNbO3 (PPLN) waveguides is mostly based on the cascaded second-harmonic generation/difference-frequency generation (SHG/DFG) process. As usual, a continuous wave (CW) and a pulsed wave are injected into a PPLN waveguide. Of them, the pulsed wave is regarded as the information carrier, and the CW is taken as the control. To transfer the information of optical codes from one wavelength to another, the codes can be applied to either the signal (CW-pumped scheme) or the pump (pulse-pumped scheme). In this work, the temporal and spectral properties of wavelength conversions during pulse propagation as well as the conversion efficiency in the two pumping schemes were compared experimentally and theoretically under different conditions of input pulse width, pump power and pump central wavelength. In the experiments, we adopted an MgO-doped PPLN waveguide, and a 40-GHz tunable picosecond-pulse source. The conversion characteristics were systematically investigated when the CW and the pulsed wave were alternatively taken as the pump at the quasi-phase-matching wavelength of the device. In the theory, we solved the coupled-mode equations and explained the physical insights for the numerical results and experimental observations. The conversion properties of the two pumping schemes were quantitatively compared. The simulated results agree well with the experimental data, and the obtained results provide some guidelines for the design and application of QPM waveguides in wavelength conversion.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIESep 11, 20060 citations

Cascaded wavelength conversions based on sum-frequency generation and difference-frequency generation

Chang‐Qing Xu, Bo Chen

A novel wavelength conversion scheme based on cascaded sum-frequency generation (SFG) and difference-frequency generation (DFG) is proposed and demonstrated in a MgO-doped LiNbO3 quasi-phase-matched waveguide. In this scheme, two pump wavelengths are set outside the communication band. It is shown that the same conversion efficiency can be achieved by use of two pump sources with lower output power (P1, P2) in this scheme compared with the conventional cascaded wavelength conversion technique based on second-harmonic generation and DFG with a single higher-power pump beam (P = P1 + P2) that is due to the use of a larger SFG nonlinear coefficient. The results significantly influence the selection of a suitable nonlinear interaction scheme for practical applications.

Optics LettersFeb 1, 200451 citations

All-Optical Quasi-phase-matched LiNbO3 Wavelength Converters

Bo Chen

This thesis describes the implementation of the all-optical wavelength converters based on quasi-phase-matched (QPM) lithium niobate (LiNbO3) crystals and some related optical nonlinear materials for optical fiber communication systems and other applications. Such devices would be the enabling technology to realize high-capacity and transparent communication networks required in wavelength-division-multiplexing systems and highly efficient laser sources at desired wavelengths. The wavelength converters discussed in this thesis are based on the three-wave mixing processes attributed to the second-order nonlinear interactions (x2,). The main challenge with a LiNbO3 QPM wavelength converter is to implement a highly efficient device, which is capable of operating at a power of hundreds of mW. For this purpose, several wavelength conversion schemes have been demonstrated and theoretically investigated, including the fiber ring resonators and a novel cascaded χ(2).∖ The former based on the conventional cascaded x(2) contains erbium-doped fiber amplifiers and other passive components exclusively as pump sources (no additional pump source is required) with excellent characteristics such as high black-box efficiency. While the encouraging properties of the latter are those pump wavelengths can be set outside the communication window, and same efficiency can be achieved by employing two pump sources with lower output power as compared with the conventional cascaded one. By taking into account the higher-order dispersion effects, pulse propagation in QPM second harmonic generation waveguides is also analyzed. In addition, the photorefractive effect (PRE) in QPM waveguides is systematically studied by using a pump-probe method, since the LiNbO3 crystals are extremely vulnerable to high-power shorter-wavelength light illumination. Both temperature and wavelength dependent results are helpful in further understanding the physical insight of the PRE, and providing a guideline for practical application of the QPM LiNbO3 waveguides.

Jul 1, 20060 citations