Polarization division multiplexing solution for submarine application at 40Gb/s and 100Gb/s

Polarization division multiplexing techniques are attractive to increase spectral efficiency of undersea systems. We will review their benefits for 40Gb/s upgrades and for new systems operating at 100Gb/s. Introduction Currently deployed undersea systems are mostly resorting on 10Gb/s technologies and exhibits a maximum capacity per fiber pair of 1.6Tb/s. These systems use modulation format coding only one bit per symbol, such as Return to Zero On Off Keying (RZOOK) or Return to Zero Differential Shift Keying (RZDPSK). By using polarization division multiplexing, information spectral density and so system capacity can be doubled. We will show that this solution is extremely interesting at 40Gb/s when associated to BPSK format [1] to upgrade dispersion managed systems designed to operate at 10Gb/s [2]. Another way to double the system capacity is to transport two bits along each polarization tributaries by using QPSK modulation. As QPSK modulation is more sensitive to non linear effects, specific submarine line should be considered here, where only fiber with positive dispersion, large effective area and low attenuation are used. This techniques is interesting at 100Gb/s [3] for new undersea systems to be deployed. Polarization division multiplexing BPSK for upgrade of undersea systems at 40Gb/s Currently deployed repeatered systems use one of two types of transmission lines. Conventional systems are based on NZDSF dispersion map which results in a large excursion of chromatic dispersion for different wavelengths.