The principle of the differential 8-level phase-shift keying(D8PSK)/amplitude-shift keying(ASK)(D8PSK/ASK) orthogonal modulation formats is investigated,and based on that,a novel scheme of optical label is proposed and demonstrated.In this scheme,D8PSK is used as the modulation formats of the payload signal whose transmission rate is 120 Gbit/s,while the 10 Gbit/s label signal uses ASK as its modulation formats,and at last,the impact of the signal extinction ratio(ER) on bit error rate(BER) is a...