IEEE Photonics Technology Letters

Abstract—The combination of RZ-DQPSK with polarization division multiplex, a 16-ary modulation scheme, allows for ultimate spectral efficiency. We raise C band fiber capacity with phase shift keying transmission beyond previously reported figures, achieving FEC limit performance over 4 fiber spans. Index Terms—Differential phase shift keying, Quadrature phase shift keying, Polarization, Wavelength division multiplexing I.