40Gb/s WDM transmission over 1.15km HC-PBGF using an InP-based Mach-Zehnder modulator at 2µm

The 2µm wavelength range has emerged as a low-loss and low-latency optical transmission window when using hollow-core photonic band gap fiber (HC-PBGF) and high-gain thulium-doped fiber amplifiers (TDFA). Various single and multichannel transmission experiments at these wavelengths have been implemented using directly modulated lasers and LiNbO3-based modulators. Here, we report the transmission performance of an externally modulated 4 x 10Gb/s NRZ-OOK WDM signal over 1.15km of low-loss HC-PBGF employing an InP-based Mach-Zehnder modulator (MZM) in the transmitter for the first time. An OSNR of 25dB on 100GHz spaced channels is required using a direct detection scheme. Furthermore, we demonstrate the lowest V(pi) InP-based MZM operating at 2µm by increasing the electro-optical overlap in the optical waveguide. The peak-peak modulation voltage is reduced significantly from 4 to 2.7V with an electro-optic bandwidth of 9GHz