A graphene-based saturable absorbing mirror and its manufacturing method

Abstract

The invention discloses a saturable absorber mirror based on graphene and a manufacturing method thereof. The manufacturing method comprises the following steps: growing graphene on a large-area substrate, then coating a silicon dioxide protective layer on the surface of the graphene, cutting into small pieces, performing smooth butt joint on the smooth end surface of an optical fiber and surfaces of the small pieces coated with silicon dioxide, and finally fixing and packaging the optical fiber and the small pieces, thus manufacturing the novel saturable absorber mirror based on graphene. The graphene serving as a saturable absorber has the advantages of low saturation intensity, ultra-fast recovery time, adjustable modulation depth, wavelength independence and the like. No damage is caused to the graphene in the preparation process, so that the complete chemical structure is kept; the silicon dioxide protective layer is coated to prevent the graphene from damage and oxidation and achieve the effect of reducing reflection of impurities; and after packaging, the absorber mirror is not influenced by the external environment. Combined with the specific structural advantage of the absorber mirror which is simple and easy to implement, the manufacturing method provided by the invention is simple, high in efficiency and low in cost, and can realize large-scale industrialization.

Description

technical field [0001] The invention relates to an optical device for a mode-locked laser, in particular to a graphene-based saturable absorption mirror and a manufacturing method. Background technique [0002] Ultrashort pulses have important applications in the fields of optical fiber communication, ultrafast optics, optical fiber sensing, industrial processing, optical information processing, laser guidance, medical treatment, inertial-constrained fast ignition, etc., and have attracted extensive research in recent years. Saturable absorbers are one of the common methods for passively mode-locked lasers to achieve ultrashort pulses. The basic mechanism of saturable absorber to achieve mode locking: when the light pulse passes through this absorber, the loss of the wing part is greater than the loss of the central part, and its intensity is enough to saturate the absorber. As a result, the light pulse passes through the absorber. is narrowed in. [0003] Traditional satu...

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Problems solved by technology

[0006] But these two methods have the following common disadvantages: 1. The production process of the graphene suspension is complicated and cumbersome; 2. The uniformity of graphene is poor, and the method of spin coating on the mirror is difficult to ensure that the graphene has been covered on the mirror , the uniformity of graphene coverage is difficult to guarantee, some places are single layer and some places are multilayer; 3. There may be some solution residues in the graphene of these two kinds of saturable absorbing mirrors; 4. Both are Not suitable for large-scale preparation

At the same time, there are also their own disadvantages: the cost of 250nm gold film mirrors is relatively high and the surface flatness of the silicon substrate is required to be high; the production of silicon dioxide / titania multilayer structure high mirrors is relatively complicated

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