All-Fiber Electro-Optic Modulator With Single-Mode-Tapered-Two-Mode-Single-Mode Fiber On Organic Electro-Optic Polymer Film

Optical fiber communication technology has gradually become one of the mainstream communication technologies due to its advantages of low loss,large communication capacity and strong anti-electromagnetic interference ability.With the wide application of optical fiber communication technology,higher requirements are put forward for the integration and cost control of electro-optical modulation devices.At present,electro-optic modulators have the problems of complex preparation process,high cost,and high coupling loss with existing optical fiber communication systems.Therefore,it is of great significance to invent electro-optic modulators that are easy to integrate into optical fiber communication systems with simple process,low cost.The single-mode-tapered-two-mode-single-mode fiber has the advantages of strong evanescent field,high refractive index sensitivity,and simple preparation process,and the coupling efficiency of coupling with standard fibers is higher than that of slab waveguides,which can reduce the requirements for the output power of the laser.These characteristics determine that the single-mode-tapered-two-mode-single-mode fiber is an ideal optical waveguide for electro-optic modulators.Organic electro-optic polymers have been widely used in the fabrication of waveguide optical modulators due to their large electro-optic coefficient,simple preparation process and low cost.Therefore,an all-fiber electro-optic modulator which is easy to integrate into optical fiber systems with simple process,low cost can be fabricated by utilizing the structural characteristics of the single-mode-tapered-two-mode-single-mode fiber and combining the advantages of organic electro-optic polymers.In this paper,an all-fiber electro-optic modulator with single-mode-tapered--two-mode-single-mode fiber on organic electro-optic polymer is realized by combining organic electro-optic polymer DR1/PMMA and single-mode-tapered-two-mode-single-mode fiber.The single-mode-tapered-two-mode-single-mode fiber structure is made by tapering the two-mode fiber of the single-mode-two-mode-single-mode fiber structure.The tapered region of the single-mode-tapered-two-mode-single-mode fiber structure is placed on the surface of the poled DR1/PMMA polymer film to realize the electro-optical modulation function.The main research contents of this paper include:1.The modulation mechanism of the all-fiber electro-optic modulator is studied.The modulation mechanism of the device is analyzed by theory and simulation of optical field evolution by element analysis methods.Secondly,the modulation mechanism of the device is verified by using the 3D finite difference beam propagation method of Rsoft software.2.The preparation,the polarization and the integration method with single-mode-tapered-two-mode-single-mode fiber structure of the organic electro-optic polymer DR1/PMMA are studied.The contact polarization and corona polarization devices are built to realize the polarization of the electro-optic polymer film,and realize the preparation and polarization of the organic electro-optic polymer film.The integration process of electro-optic polymer with single-mode-tapered-two-mode-single-mode fiber and coreless side-polished fiber is studied.An all-fiber electro-optical modulator was fabricated by placing the single-mode-tapered-two-mode-single-mode fiber on the poled polymer film.3.The modulation depth and bandwidth of the electro-optical modulator are measured,and the total harmonic distortion is analyzed.The extinction ratio of the modulator is 6.5 d B,respectively,which are comparable to existing graphene-based all-fiber electro-optic modulators and silicon electro-optic modulators.The 3d B bandwidth of the device is 1.4 k Hz,which is much lower than the bandwidth of organic electro-optic polymer waveguide modulators.The total harmonic distortion of the device is less than 2.5 % with an applied modulation voltage at 1-5kHz.