ISRS-Supported Ultra-Wideband Transmission in S, C, L, U, and Extremely Long Wavelength Bands With PPLN-Based OPA/EDFA Hybrid Repeater

We demonstrate ultra-wideband long-haul fiberoptic transmission with 27.0-THz signal bandwidth across the S, C, L, U, and extremely long wavelength (X) bands spanning a wavelength range of 238 nm (1464.01–1702.64 nm). The longer wavelengths beyond the U-band (1625–1675 nm) are lossy in silicacore fibers, but with support from power transition caused by inter-channel stimulated Raman scattering (ISRS) in multiband transmission, such wavelengths can be utilized as low-loss wavelength resources for data transmission. We denote this band beyond the conventional telecommunication bands as the X-band and explored its potential in ultra-high-capacity long-haul transmission systems. Inline amplification in bands other than the C/L-band, including the X-band, was performed using an optical hybrid repeater with waveband conversion using optical parametric amplifiers (OPAs) based on in-house periodically poled lithium niobate (PPLN) waveguides and erbium-doped fiber amplifiers (EDFAs). By designing the fiber launch condition to account for the ISRS, we achieved net capacities of 189.5 Tbps and 160.2 Tbps after 560-km and 1040-km transmission, respectively, over an 80-km-span standard single-mode fiber lumped-amplified link with Tbps-class channels in the X-band.