The invention relates to a method and a device for erasing and interposing a differential 8-
phase shift keying /
amplitude shift keying (D8PSK / ASK) orthogonal optical
label based on an electro-absorption modulator (EAM). A coupler divides orthogonal optical
label information into two paths with the same power; amplitude information in an orthogonal modulating
signal is demodulated by an upper
branch signal through an
amplitude shift keying signal demodulator, and the demodulated amplitude information is logically negated and loaded onto an
electricity input port of the EAM through a phase reverser; a lower
branch signal is loaded onto an optical input port of the EAM after being delayed and amplified so as to erase the amplitude information on an optical
carrier signal; and an optical
band pass filter filters
chirp of an optical carrier on which the old
label information is erased, the filtered optical carrier is loaded onto the optical input port of the EAM after an Er-doped
fiber amplifier amplifies the power of the filtered optical carrier, and new label information is loaded onto the amplitude of the optical carrier in an
amplitude shift keying modulation mode so as to finish the interposing of a new label. The EAM does not have
side effect on a load when the label is erased and interposed, and has
chirp controllability, low driving
voltage, low polarization sensitivity, small volume and low price, so that the whole network
system has a simple structure and low cost, and promotes the development of the full optical
label switching technology.