A monolithic integrated
laser chip based on amplification feedback to realize straight-strip
bandwidth expansion comprises a lower limiting layer, an
active layer, an upper limiting layer, a
waveguide layer, a P+
electrode layer and an N+
electrode layer. The
active layer is manufactured on the lower limiting layer, the upper limiting layer is manufactured on the
active layer, the
waveguide layer is strip-shaped and longitudinally manufactured in the middle of the front of the upper limiting layer, the P+
electrode layer is divided into three sections by isolating grooves and manufactured on the
waveguide layer, the N+electrode layer is manufactured on the back of the lower limiting layer, the three sections of the P+electrode layer are a DFB (distributed feedback Bragg)
laser area, a passive phase adjusting area and an active amplification feedback area respectively, a distribution feedback Bragg
grating layer is manufactured on a portion, corresponding to the upper limiting layer, of the DFB
laser area, and
gain peak between the active layer corresponding to the passive phase adjusting area and the active layer corresponding to the DFB laser area and the active amplification feedback area has 90nm of blue shift. The monolithic integrated laser
chip can break through limitation of straight-strip bandwidth of a common laser
chip, and laser straight-strip
bandwidth expansion can be realized through a method which is ingenious, effective and low in cost.