A double-peak ultra-narrow-band steep optical interference filter and its manufacturing method

Abstract

The invention discloses a double-peak ultra-narrow-band steep optical interference filter and a manufacturing method thereof, comprising a base, a narrow-band filter and a four-cavity etalon, and the base is provided with a narrow-band filter and a four-cavity etalon. The four-cavity etalon is composed of four-cavity fused quartz and vacuum coating, and a layer of 1 / 4 optical thickness of SiO2 is coupled between each cavity to form a four-cavity structure. The narrow-band filter matches the four-cavity The etalon, the narrowband filter is composed of WMS15 substrate and coating; the present invention is designed to realize the combination of narrowband filter and four-cavity etalon, the narrowband filter is prepared by WMS15 substrate and coating coating, and the four-cavity etalon It is made of four-cavity fused silica combined with vacuum coating and bonding process, which meets the passband 10GHz isolation and the interval of 30dB is less than 21GHz, and the filter output of the four-cavity etalon is peaked and multi-peaked with a period of free spectral region, which is applied to wavelength locking. Can reach double peaks and steep cut-off.

Description

technical field [0001] The invention relates to the technical field of filters, in particular to a double-peak ultra-narrow-band steep optical interference filter and a manufacturing method thereof. Background technique [0002] In the ultra-high-precision fiber optic gyroscope project, it is required that the pass-band spacing of 7GHz (0.056nm) double-peak insertion loss is less than 3dB, and the ultra-narrow-band filter with isolation greater than 30dB outside the 21Ghz (0.17nm) band can be used in space; [0003] This requires the use of optical interference filters, which use the principle of interference to cut off unnecessary or harmful wavelength light sources, and only pass signal light. The structure is simple and easy to use. It is widely used in optical communications, biometrics, and various optical signals. In the field of detection, most of these filters are vacuum coating technology, and the coating system of multi-cavity structure is realized on the glass sub...

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Problems solved by technology

[0003] This requires the use of optical interference filters, which use the principle of interference to cut off unnecessary or harmful wavelength light sources, and only pass signal light. The structure is simple and easy to use. It is widely used in optical communications, biometrics, and various optical signals. In the field of detection, most of these filters are vacuum coating technology, and the coating system of multi-cavity structure is realized on the glass substrate. At present, the coating technology is limited by factors such as the bandwidth of the monitoring light source, signal processing capability, and the stability of the refractive index of the film layer. In the 1550nm band, the narrowest flat-top and steep filter passband can only reach 30GHz. The other is the etalon as a filter, which can be used as a filter with a passband below 1GHz. Usually, the etalon has a single-cavity structure and cannot achieve flattening. Top and double peaks, no etalon with structure above three cavities, therefore, the present invention proposes a double peak ultra-narrow-band steep optical interference filter and its manufacturing method to solve the problems existing in the prior art

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