Narrow linewidth laser

Abstract

The invention discloses a narrow linewidth laser which comprises a passive annular resonant cavity, an FP resonant cavity and a first gain region, the passive annular resonant cavity and the FP resonant cavity are matched to form an M-Z (Mach-Zehnder Interference Structure) composite outer cavity structure, and the M-Z composite outer cavity structure is at least used for providing wavelength selection and narrowing the linewidth of the laser. And the first gain region is arranged on the outer side of the M-Z composite outer cavity structure and is at least used for providing gain for the whole laser. The narrow linewidth laser provided by the embodiment of the invention is simple in structure, high in side mode rejection ratio, narrow in linewidth and high in output power; by further integrating the third gain region, wide-spectrum, low-consumption and fast tuning can be realized, and tuning management is simple; in the prior art, for example, monolithic integration is adopted, butt joint coupling loss of the gain area and the waveguide area and narrow linewidth limitation caused by the butt joint coupling loss can be further avoided, meanwhile, the device can be manufactured through an integrally-formed semiconductor process, and the device is low in cost, higher in stability and reliability and higher in severe environment resistance.

Description

technical field [0001] The present application relates to a laser, in particular to a tunable narrow linewidth laser. Background technique [0002] Narrow linewidth lasers are of great application value because of their excellent coherence as high-quality light sources for information communication (sensing). Narrow linewidth lasers can not only be used in cutting-edge scientific research such as high-precision spectral measurement, quantum (atomic) frequency standards, etc., but also the core components of coherent optical communication and distributed optical fiber sensing, which can be widely used in large-capacity laser communication, optical fiber and high-sensitivity coherent detection. Broad-spectrum tunable narrow-linewidth lasers as light sources can further enhance their core competitiveness in the above application fields. [0003] In view of its wide and attractive application prospects, many researchers and investment institutions have invested in the study of...

AI Technical Summary

Problems solved by technology

However, due to the limited cavity length of traditional DFB and DBR lasers, it is difficult to obtain extremely narrow linewidth tuning even though complex grating structures are used to select wavelengths, which directly restricts their applications in the above fields.

[0005] In 2001, some researchers proposed that a weakly coupled ring external cavity semiconductor laser achieve narrow linewidth, but the single ring external cavity laser has not been realized due to too much loss in the ring (Appl. Phys. Lett., 79(22) 3561, (2001)

Although the above-mentioned lasers achieve chip-level narrow linewidth performance, all structures here are not only based on the dielectric photonic integrated circuit as the linewidth narrowing unit and wavelength tuning unit, the III-V SOA acts as the gain region, and the two are mixed and integrated to form a narrow line Widely tunable semiconductor lasers, and these dielectric waveguide photonic integrated circuits are very complex, and the wavelength selection, narrowing and tuning units of the laser are all based on the dielectric photonic integrated circuit. In order to achieve wide-spectrum tuning, narrow linewidth and high side mode suppression ratio output , it is usually necessary to adjust the refractive index of multiple resonant cavities through the electrothermal effect to obtain the optimal effect, which leads to complex electrothermal management and slow tuning speed

[0006] The applicant has previously proposed a monolithic integrated narrow linewidth laser (PCT / CN2017 / 110792), but there are defects such as low output power and poor side mode suppression ratio, which directly hinder its application in the corresponding information system

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