The invention relates to the technical field of a
semiconductor laser, and proposes a single-mode emission orbital
angular momentum (OAM)
laser. A cavity body of a
resonant cavity of the
laser is of amicro column, micro ring or micro disc structure for supporting an echo wall mode, a
grating or defect is etched on an outer side surface of the cavity body of the laser, the echo wall mode with special angular
quantum number can be selected as a hot shot mode of the laser, the selected mode is vertically scattered and output by a top
grating, the output is a travelling
wave mode with a vortex phase, namely an OAM mode, the top
grating is arranged at a position, near to an outer side edge of a
micro column, of a grating layer and comprises a real part and a virtual part, the real part and thevirtual part comprise two groups of gratings and are used for respectively modulating effective
reflectivity of the mode, so that scattering output of the travelling
wave mode is formed. The laser issmall in cavity volume and low in loss, and thus, ultrahigh-speed modulation can be achieved. The
semiconductor laser has the characteristics of small volume, single-mode working and low
threshold current, and is convenient to detect, a two-dimensional array is easy to integrate, output light is easy to couple to
optical fiber, and various advantages can be achieved on different material systems.