Wave-band multiplexed 20-Gb/s QPSK simultaneous transmission over 4-km holey fiber in O- and T-bands with homodyne detection

Abstract

A sharp growth in the transmission capacities of photonic transport networks has necessitated an increase in the spectral efficiency and number of wavelength channels. Advanced photonic transport technology in the T-band (thousand band: 1000–1260 nm, available bandwidth of 61.9 THz) is a promising solution to expanding the usable wavelength channels for optical communication to increase the available capacity. The available bandwidth in the T-band is approximately five times that of the conventional C- and L-bands, and, therefore, we propose an ultra-broadband photonic transport system that employs waveband multiplexing technology which is compatible with both novel and conventional wavebands. Wavelength-tunable quantum dot (QD) laser technologies aid the availability of the T-band with its wide wavelength tunability. An endlessly single-mode holey fiber (HF) is used as a wave-band multiplexing transmission line in the O- and T-bands. Optimizing the spectral efficiency is key to realizing high-capacity transmission using advanced digital signal processing (DSP) technology with a coherent detection scheme. In the study, we successfully demonstrated error-free transmission with 20-Gb/s quadrature phase-shift keying (QPSK) using homodyne detection receivers in the O- and T-bands simultaneously over a 4-km long HF. The measured bit error rates (BERs) were within the forward error correction limit of 2×10-3 in both the O- and T-bands. The large number of wavelength channels with conventional use of the O- and T-bands should help increase the total capacity of an optical fiber to meet the growth in demand of optical communication data traffic.