Single-mode emission orbital angular momentum (OAM) laser

Abstract

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.

Description

technical field [0001] The invention belongs to the technical field of semiconductor lasers, and relates to a single-mode surface emitting OAM laser. Background technique [0002] With the rapid development of the communication industry, the demand for communication capacity from big data, cloud computing, and the Internet of Things has grown exponentially. [0003] Electromagnetic wave angular momentum includes two parts: spin angular momentum (SAM) and orbital angular momentum (OAM). where the SAM is related to the photon rotation and has only two orthogonal states. OAM is related to the spatial distribution of photon wave functions, and has the basic properties of "vortex electromagnetic waves", which are manifested as having vortex-like phases and propagating along vortex lines. The OAM beam has a vortex phase distribution and an annular hollow intensity distribution. In the vortex electromagnetic wave, each photon carries the orbital angular momentum of l, and the op...

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Problems solved by technology

However, it cannot be pumped electrically, and the active region is exposed on the surface, and the surface recombination will be very serious, which will affect the performance of the laser.

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