Ytterbium-doped silica fiber light darkening test device and method

Abstract

The invention discloses a ytterbium-doped silica fiber light darkening test device and method. The device comprises a signal source, an optical fiber flange, a pumping source, a wavelength division multiplexer, an ytterbium-doped fiber, an optical fiber beam combiner and a power detector, and laser output by the signal source passes through the optical fiber flange and then is combined with pumping light output by a first pumping source through the wavelength division multiplexer to form combined light. The combined light and the pump light output by the second pump source are respectively input through the signal end and the pump end of the optical fiber beam combiner. The output light of the optical fiber beam combiner is transmitted along the ytterbium-doped optical fiber, the output end of the ytterbium-doped optical fiber is welded with the input end of the cladding light stripper, and the output light beam of the cladding light stripper enters the power detector through the filter. The device has the beneficial effects that the ion inversion rate in the light darkening test is higher, the time for testing the light darkening loss is shorter, and the precision of the tested light darkening loss is higher. The structure is simple and compact, and the test stability is better. Different pumping injection modes are adopted, and the light darkening performance under several test conditions is compared.

Description

technical field [0001] The invention relates to the field of optical fiber testing, in particular to a photo-darkening testing device and method for ytterbium-doped silica optical fiber. Background technique [0002] Due to the characteristics of good heat dissipation, compact structure, easy maintenance, and easy realization of high-power single-mode laser output, fiber lasers are widely used in material processing (laser drilling, laser marking, laser cutting, laser cladding, laser welding, etc.), medical , communications, remote sensing, and national defense security and other fields have remarkable application prospects. However, in the application process of fiber lasers, there will be a phenomenon that the laser output power gradually decreases with time, which is the photodarkening effect. The photo-darkening effect of the active fiber reduces the working efficiency of the fiber laser, and there is a risk of burning due to increased heat generation. Therefore, in or...

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Problems solved by technology

However, the test time of the strong light test method is long and the cycle is long; the weak light test method is an indirect test method. The weak light test method uses visible light with low power as the detection light source. Generally, 633nm red light is selected as the detection light source. The laser is injected into the ytterbium-doped silica fiber, and the change of the red light power is observed, so as to calculate the photo-darkening performance of the ytterbium-doped silica fiber

However, the weak light test method is only an indirect test, which can only be compared through relative values, and cannot directly test the loss of light darkening

[0004] However, in this application, the inventor found that the existing photo-darkening test device has the following problems during the implementation of the present invention: the existing strong light test method for the photo-darkening effect of ytterbium-doped optical fiber, by using ~1μm The high-energy laser is used as the detection light source, and the wavelength of the detection light is far away from the photo-darkening "color center" in the ultraviolet-visible band. The photo-darkening effect is not obvious, and it is difficult to detect the photo-darkening performance of ytterbium-doped optical fiber with low photon darkening effect; In the weak light test method of the existing gain fiber photon darkening test system, the patent connects a collimator lens, a semiconductor laser output wavelength filter, a gain fiber excitation wavelength filter and a narrow-band optical filter at the output end of the gain fiber in sequence. When the unabsorbed high-energy pump light passes through the collimating lens and three filters, the thermal effect will affect the stability of the test system, and the collimating lens and three filters are connected between the output end of the gain fiber and the power meter , the system structure is complex, and the stability of the optical structure is poor, which affects the stability of the test system

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