Grating-integrated wedge-shaped edge-emitting terahertz quantum cascade lasers

Abstract

The invention discloses an edge emitting terahertz quantum cascade laser integrated with a wedge-shaped structure of a grating and a manufacturing method thereof. The edge emitting terahertz quantum cascade laser integrated with the wedge-shaped structure of the grating at least comprises a DBR (distributed bragg reflection) grating waveguide, a rectangular straight waveguide and a wedge-shaped waveguide which are connected sequentially, wherein one end of the wedge-shaped waveguide is a narrow end surface and the other end of the wedge-shaped waveguide is a wide end surface; the narrow end surface of the wedge-shaped waveguide is connected with the rectangular straight waveguide. According to the invention, due to adoption of the wedge-shaped waveguide structure, the gain area of the laser is enlarged, the output light power is improved, the far field light spot divergence angle of the laser is reduced, and the emergent light beam quality is improved; by virtue of a one-cascade DBR grating structure, the single longitudinal mode lasing is realized, the reflection of lasing light is provided, and a traditional end surface coating technology is replaced.

Description

technical field [0001] The invention belongs to the technical field of laser semiconductors, and relates to a terahertz quantum cascade laser, in particular to an edge-emitting terahertz quantum cascade laser with an integrated grating wedge structure. Background technique [0002] Terahertz (hereinafter referred to as THz, 1THz=1012Hz) band refers to the frequency in the electromagnetic spectrum from 100GHz to 10THz, the corresponding wavelength is from 3 mm to 30 microns, and the electromagnetic spectrum region between millimeter wave and infrared light. Due to the lack of effective THz radiation generation and detection methods, electromagnetic waves in the THz band have not been fully studied and applied for a long time, which is called the "THz gap" in the electromagnetic spectrum. The THz radiation source is a key device for the application of THz technology. Among many THz radiation generation methods, THz quantum cascade laser (hereinafter referred to as THz QCL) ha...

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Problems solved by technology

[0003] In view of the shortcomings of the prior art described above, the object of the present invention is to provide an edge-emitting terahertz quantum cascade laser with an integrated grating wedge structure and its manufacturing method, which is used to solve the problem of the rectangular strip structure in the prior art. Due to the small gain difference between the longitudinal modes and the weak selectivity of the longitudinal mode in the Brie-Perot cavity terahertz quantum cascade laser, it is difficult to realize the problem of single longitudinal mode operation, and the width of the rectangular strip structure of the single transverse mode lasing is narrow , causing the far-field spot emission angle to be too large, which reduces the quality of the outgoing beam

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