A novel scheme of spectrum equalization for effectively improving receiving responsibility of amplitude shift keying(ASK) payload by applying an optical band-pass filter(OBPF) is proposed,which is utilized in amplitude shift keying/frequency shift keying(ASK/FSK) orthogonal modulation optical label switching system.The transmission performances of 40 Gbit/s ASK/FSK optical label switching system with three types of OBPFs are demonstrated and compared by simulations.The results reveal that a Butt...