Efficient and Broadband All-Optical Wavelength Conversion Between C and O Bands in Nanophotonic Lithium Niobate Waveguides
Junjie Wei, Chen Cheng, You Wu, Cheng Zeng, Ming Tang, Jinsong Xia
Abstract
With the emergence of 5G communication, the traditional wavelength division multiplexing (WDM) technology within the C-band faces challenges in meeting the increasing data traffic demands in optical transmission networks. To increase the transmission capacity, using extended wavebands beyond the C-band, such as S, L, and O bands, is a promising solution. An efficient approach to utilizing multiple optical wavebands is all-optical wavelength conversion (AOWC), which is fully transparent to symbol rate and modulation format. In this paper, we experimentally demonstrated broadband AOWC of a 56Gbaud on-off keying (OOK) signal between C and O bands in a single thin-film periodically poled lithium niobate (PPLN) waveguide. For both C-to-O and O-to-C AOWCs, a marginal 0.2 dB received optical power (ROP) penalty was successfully achieved between the idler and back-to-back (B2B) signal waves. Additionally, for more detailed performance evaluations, we measured the 3-dB signal bandwidths and on-chip conversion efficiencies (CEs) in 5mm and 1cm long PPLN waveguides for both C-to-O and O-to-C AOWCs. As a result, the maximum 3-dB signal bandwidth of 85 nm (from 1500 to 1585 nm) was obtained in the 5-mm-long PPLN waveguide and the maximum on-chip CE of -7.2 dB was obtained in the 1-cm-long PPLN waveguide.