Abstract

We demonstrate a 38.4-Tbps (60 ch. × 640 Gbps) wavelength-division multiplexing (WDM) transmission across 5 × 80-km G.654.E single-mode fibers over 6 THz within L- and U-bands. The U-band (1625–1675 nm) is promising as a next transmission band for multiband networks because of its low transmission loss compared with E- and O-bands, but there are few demonstrations of coherent WDM transmission with the U-band. One reason is that promising optical components, especially for optical transceivers, are underdeveloped for the U-band. An optical parametric amplifier (OPA) using a periodically poled LiNbO₃ (PPLN) waveguide has wide-gain bandwidth and wavelength conversion function, which allows the use of commercially available optical components for new bands. We achieve L- and U-band digital coherent WDM transmission within 1597.2–1649.9 nm (181.7–187.7 THz) using PPLN-based optical parametric inline amplification and wavelength-band conversion.