Research For The Optoelectronic Characteristics Of Graphene Device In Optical Fiber Communication System

Graphene, as a new material, has attracted great interest in optical communication system according to its excellent optoelectronic characteristic since it was discovered in 2004. Also, its great performance in mobility, third-optical nonlinearity, saturation absorption and wide-band absorption make it a popular material in different research area. But the absorption rate of vertical incident light of graphene is only 2.3%, which extremely limits graphene's application in optical fiber communication system. How to improve the absorption rate of graphene and stimulate the excellent optoelectronic properties in monolayer graphene have become a research hotspot in academia.In order to enhance the light absorption in graphene, we adopted some different fiber structure to verify graphene's superior optical third-order nonlinearity and photoelectric conversion characteristics. We proposed a graphene attached onto titled fiber bragg grating structure to perform the four-wave-mixing experiment. The insertion loss caused by graphene is about 7.2dB and we got a four-wave-mixing conversion efficiency at-34.9d B with a pump light at 500 mW. We further studied the tendency of the conversion efficiency varies with different pump power, wavelength detuning, propagation length and titled angle of the bragg grating. Then we fabricated a microfiber-graphene photodetector by depositing two metal electrodes on a glass substrate and transferring monolayer graphene sheet onto the electrodes. The simulation results show the proposed structure has a broadband absorption characteristic. The insertion loss caused by the connection between graphene and microfiber is estimated to about 11.8d B. And we got a maximum of responsivity of 2.81mA/W with the pump light at 1dBm. The tendency of the responsivity under different incident light power is also discussed.Moreover, we proposed and fabricated a silicon device structure. By introducing a silicon microring resonator and Sagnac reflector into a Mach-Zehnder interferometer, an electromagnetically induced transparency spectrum can be generated. Enhanced fast light and low-distortion slow light can be observed at different resonant wavelengths in the same device. Our study has some guidance significance to the research of the optical control system. And it also has great influence on the following up study by depositing monolayer graphene onto the silicon waveguide.