Research On A Novel Tunable Filter And Polarization Beam Splitter By Using Micro-Optofluidic Technology

Both the tunable narrow-band filter and the tunable polarization beam splitter are important optical functional devices in optical systems,which has wide application value in many fields such as optical signal processing,optical sensing and optical fiber communication.Firstly,a novel tunable narrow-band filter based on one-dimensional sub-wavelength grating structure is designed,which use microfluidic technology to realize dynamic regulation of output wavelength.Based on strict mode theory,the simulation program was programmed and the optical performance was simulated.The simulation results show that the wavelength tuning range of the device can reach 28 nm,and its the FWHM is always less than 0.03 nm,and its quality factor(Q)can be over50000.In addition,a high sensitivity liquid refractive index sensor based on the tunable filter is designed,which has many advantages such as high measurement accuracy,simple structure,easy measurement,rapid measurement and easy integration.It will have wide applications in the fields such as bio-photonic sensing and chemical analysis.Secondly,in order to solve the polarization dependence problem of the tunable narrow-band filter based on one-dimensional sub-wavelength grating structure,we take advantage of the polarization insensitivity of two-dimensional sub-wavelength gratings.A novel tunable optical narrow-band filter independent of polarization state is proposed,which isbased on two-dimensional sub-wavelength gratings.The optical performance of the device is simulated,the simulation results suggest that the device can achieve synchronous filtering of TE and TM wave.Its wavelength tuning range is up to 37 nm,and its FWHM is always less than 0.8 nm,and the sensitivity(S)and quality factor(Q)are up to 336nm/RIU and 2000,respectively.Finally,a novel tunable polarization beam splitter with one-wavelength grating structure by using micro-optofluidic technology is designed.Its dynamic regulation of the two polarization states of TE and TM wave in the reflection and transmission regions of the grating is realized at the wavelength of 1550 nm.The optical performance of the device is numerically investigated by using rigorous mode theory.The simulation results reveal that when the refractive index of the microfluid is 1.43,the reflectance extinction ratio and transmission extinction ratio are about 27.9 dB and 27 dB,respectively.When the refractive index of the microfluid is 1.53,the reflectance extinction ratio and transmission extinction ratio are about 28.5 dB and 29.9 dB,respectively.The device has many advantages such as simple structure,large tolerance of production process.