Multi-mode interference effect-based widely-tunable single-frequency fiber laser

Abstract

The invention discloses a multi-mode interference effect-based widely-tunable single-frequency fiber laser. The laser comprises a high-reflectivity chirped fiber grating, a high-gain fiber, a low-reflectivity chirped fiber grating, a pumping source, an optical isolator, an optical circulator, a fiber etalon and an SMS fiber structure device, wherein the high-reflectivity chirped fiber grating, thehigh-gain and the low-reflectivity chirped fiber grating are sequentially connected to form a short-line resonant cavity part, the optical circulator, the fiber etalon and the SMS fiber structure device form an annular cavity, a stress loading device is fixedly arranged on an upper surface of the SMS fiber structure device, the transmitting wavelength is changed and the tunable filtering is achieved by loading stress onto the SMS fiber structure device, and single-frequency fiber laser output with stable power and wide tuning range is finally achieved. The laser combines the advantages of a composite cavity structure, has the advantages of all-fiber structure, wide wavelength tuning range and the like and can be widely applied to the fields of optical communication, sensing and spectrum.

Description

technical field [0001] The invention belongs to the technical field of fiber lasers, in particular to a single-frequency fiber laser with a wide tunable range based on multimode interference effects. Background technique [0002] Tunable single-frequency fiber laser is a very important laser light source, which has important application value in optical communication, sensing, spectroscopy and other fields. The principle of general tuning is to change the output wavelength of the laser by changing the transmission wavelength through some devices. Currently commonly used tuning devices such as volume gratings, birefringent filters, electro-optic crystals, Fabry-Perot (F-P) etalons, etc., can be achieved by inserting such tuning devices into a line cavity, ring cavity or composite cavity. Tune the single frequency laser output. However, these methods all have the disadvantages of breaking the all-fiber structure, large volume, need for spatial alignment, and high cost. In a...

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Problems solved by technology

[0003] Relevant patents include: (1) In 2015, South China University of Technology applied for a wide tunable single-frequency fiber laser source for coherent optical OFDM systems, and inserted tunable F-P filters into the ring cavity outside the online resonator device to realize a wide tunable single-frequency fiber laser [public number: CN 105428973 A], but the tunable filter used in this patent is expensive, and the tuning bandwidth and precision are limited by the filter device itself

(2) In 2017, Fujian Haichuang Optoelectronics Co., Ltd. applied for a tunable laser. By changing the angle of the F-P etalon, the transmission wavelength can be changed and the tunable laser can be operated quickly [public number: CN 206611012 U ], but this patent is not a fiber laser, the collimation work is more difficult, and it is not a single-frequency laser output characteristic

(3) In 2018, Nanjing University of Posts and Telecommunications applied for a tunable fiber laser. By fusing single-mode fiber pellets and special fiber pellets between single-mode fiber and special fiber, a peanut knot structure was formed to realize mode selection and Thermally tunable all-fiber laser [publication number: CN 208045931 U], but this patent is not a single-frequency laser output characteristic, and it is more complicated to operate

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