Wide-range adjustable optical fiber filter based on SPR (Surface Plasmon Resonance) principle

Abstract

The invention provides a wide-range adjustable optical fiber filter based on an SPR (Surface Plasmon Resonance) principle. The device is composed of a broadband light source 1, a side-cast D-type optical fiber 2 which is packaged by a refractive index solution and is plated with a metal film and a two-dimensional material film, a side-cast D-type optical fiber 3 which is packaged by a refractive index solution and is plated with a metal film and a two-dimensional material film, a spectrum analyzer 4 and an isolator 5. The broadband light source generates the SPR phenomenon near the metal films of the optical fiber 2 and the optical fiber 3, the resonant wavelength is tuned according to different packaging refraction, and the wide-range adjustable filtering effect is achieved through cascade connection. The preparation is simple, the cost is low, the filtering effect is good, and the formed optical filter is easy to integrate and can be used for optical fiber communication.

Description

(1) Technical field [0001] The invention relates to a wide-range adjustable optical fiber filter based on the SPR principle, which can be used for realizing good broadband polarization filtering function in different frequency bands, and belongs to the technical field of optical fiber filtering. (2) Background technology [0002] Optical fiber filters are one of the basic key components in wavelength division multiplexing (WDM) optical communication systems and sensing systems. All-fiber tunable filters with tunable wavelength, low insertion loss, and easy integration with optical fiber communication systems are receiving increasing attention. favored by researchers. The fiber filter designed according to the principle of light interference and diffraction is mainly used to filter out the useless frequency (wavelength) components in the signal. According to the principle of light interference and diffraction, combined with the light-guiding properties of optical fibers, a v...

AI Technical Summary

Problems solved by technology

[0005] Document CN201810346092.7 discloses a photonic crystal fiber with tunable broadband polarization filtering function, which proposes a photonic crystal fiber with a new structure with tunable broadband polarization filtering function. Because the fiber itself has high birefringence characteristics, it does not need to change the established The optical fiber structure can realize the broadband polarization filtering function at different wavelengths only by changing the refractive index of the filled liquid. Although this invention also applies the principle of SPR, the preparation and universality of photonic crystal optical fibers are not so high. For Subsequent development is not strong, and the filter has the problem of insufficient filtering

[0006] Document CN201920365606.3 discloses a high damage threshold polarization filter, which proposes a combination of hollow-core antiresonant fiber and SPR to achieve good polarization performance while eliminating inherent loss and optical nonlinearity caused by the material itself. Loss, but the filter has the complexity of the fiber involved, and there are problems such as narrow application range

[0007] Document CN201910311900.0 discloses a fully polarization-maintaining broadband controllable optical fiber filter, which proposes a fully polarization-maintaining broadband controllable optical fiber filter, but the overall structure is too cumbersome, and the scope of application is too concentrated, mainly at 1500nm about

[0008] An adjustable ultra-narrowband optical fiber filter disclosed in document CN202011586538.7 proposes to be formed by cascading two or more optical fiber rings, and each optical fiber ring is connected by two optical fiber couplers through two pairs of ports. The ring-shaped optical fiber structure formed, although the filter can simultaneously achieve high transmission, ultra-narrow-band filtering and large free spectral range, but the filter is used in the band around 1550nm, the application range is too limited

[0009] Document CN201910948040.1 discloses a fiber-type ultra-wideband band-stop filter, which proposes an ultra-wideband filter combined with a first single-mode fiber, a coated chirped long-period fiber grating and a second single-mode fiber , but the fiber grating is expensive, not conducive to mass production, and the structure is not simple, and the range of action is still the traditional 1200-1800nm

[0010] Document CN201920860337.8 discloses a broadband variable wavelength tunable optical fiber filter, which proposes a filter composed of a beam emitting device, a beam receiving device, a mechanical rotating mirror, a focusing element, a grating and a total reflection mirror. The structure used is too cumbersome and requires high precision. Although it has an adjustable function, the part with good wavelength sensing effect is narrow

[0011] The literature "Jia Pinggang, Zuo Fangjun, Liu Lei, etc. Performance optimization design method of surface plasmon resonance photonic crystal fiber polarization filter [J]. Journal of Chongqing University, 2021,44(9):139-146." A common photonic crystal fiber based on surface plasmon resonance is used as a carrier. Through local parameter adjustment design, a PCF polarization filter performance optimization design method based on the SPR effect is proposed, but the best part of the discussion of the filtering range is concentrated At about 1400nm, the half width is also very narrow, and the adjustability is poor

[0012] Literature "C. Liu, LY. Wang, FM. Wang et al. Tunable single-polarization bimetal-coated and liquid-filled photonic crystal fiber filter based on surface plasma resonance [J]. Appl. Opt., 2019, 58(32) :6308-6314." proposed a double-metal coated single-polarization photonic crystal fiber (PCF) filter based on surface plasmon resonance (SPR), which can filter at 1310nm and 1560nm at the same time, but it cannot be adjusted characteristics, filtering can only be performed at a fixed wavelength

[0013] The document "EC.Chen, S.Liu, P.Lu et al. Tunable 2mu m Fiber Laser Utilizing a Modified Sagnac Filter Incorporating Cascaded Polarization Maintaining Fibers [J]. IEEE Photon. Journal, 2020, 12(1)." proposed a method based on Widely tunable 2μm fiber laser with improved Sagnac filter, which combines cascaded polarization-maintaining fibers and uses free tuning steps to obtain a tuning range of more than 40nm, ranging from 1859nm to 1901nm, but its filtering range is too narrow and the preparation is complicated

Images