The Research On Controllable Polarization Analyzer And Polarization Beam Splitter By Using Waveguide Structures

Controllable polarization beam splitter and controllable polarization analyzer based on waveguide structure are the novel optical functional element,whose out-put polarization state can be dynamically manipulated for ortlhogonal polarization splitting and analyzing.The proposed devices have wide potential application in the photonic integrated circuits.First of all,two kinds of novel controllable polarization analyzers based on waveguide structure are designecd,which are S-shape waveguide and deflection ridge waveguide respectively.Bying using the anisotropy and large birefringence.of the liquid cryst.al laterial,tlie controllable.output of transverse electric wave and transverse magnetic wave can be realized based on the electro-optical effect.The optical perfonmance of the proposed device is numerically demonstrated by beam propagatio methocd(BPM).For deflection ridge waveguide polarization an-alyzer,when voltage U0 is applied between electrodes,simulation results suggest that the excess loss in the polarization analyzer is about 0.002dB for TE mode and 29.6dB for TM mode,respectively.The corresponding extinction ratios are about 29.598dB,which means that the TE mode detection is completed.While no voltage is applied,the excess loss in the polarization analyzer is about 29.8dB for TE mode and 0.003dB for TM mode,respectively,Tlie corresponding extinction ratios are about 29.797dB,which means that the TM mode detection is completed.For S-sbape waveguide polarization analyzer,when voltage U0 is applied between electrodes,simulation results suggest that the excess loss in the polarization an-alyzer is about 0.002dB for TE mode and 29.8dB for TM mode,respectively.At this point,the corresponding extinction ratios are about,29.798dB,which means that the TE mode detection is completed While no voltage is applied,the excess loss in tlie polarization analyzer is about 29.9dB for TE mode and 0.001dB for TM mode,respectively.The corresponding extinction ratios are about.29.899dB,which means that the TM mode detection is completed.In additioni,the proposed de-vice is insensitive to wavelength and fabrication error.The proposed devices have the advantages such as simple dynamic manipulate,easy design and fabrication and simple structure,which these two novel controllable polarization analyzers has wide applications in integrated photonic systems.Secondly,we also cdesigned a novel controllable polarization beam splitter based on the MMI waveguide.Bying using tlhe anisotropy and large birefrin-gence of the liquid crystal material,the controllable output of transverse electric wave and tiransverse magnetic wave can be interchanged and outplt basecd on the electro-optical effect.The optical performance of the proposed dcevices is numeri-cally investigated by beam propagation method(BPM).The liquid crystal cdirector is horizontal while no voltage is applied.Accorcding to the simulated results,the corre,sponding extinction ratios for TE and TM inodes are about,28.7dB and 29dB,respectively.In addition,the excess loss in the polarization beam splitter is very low,aboiut.0.024dB for TE mode and 0.012dB for TM mode,respectivcely.The TE mode is almost fullxy into the ipsilateral straight waveguide on opposite sicdes,while the TM mode is almost totally the ipsilateral straight waveguide on the sanme side,due to self-imaging effect.When a saturation voltage is applied between elec-trodes.Here,its extinction ratios for TE and TM modes are about 33.0dB and 29.6dB,respectively.The excess loss is about 0.009dB for TE mode,and it is cabout.0.0l8dB for TM mode.The TM mode is almost fully into the ipsilaterfal straight waveguide on opposite sides,while the TE mode is almost totally the ipsi-lateral straight waveguide on the same side,due to self-imaging effect.Furthermore,we have analyzed its performance dependence of the designed optical component on wavelength and tle fabrication tolerance.It suggests that the response of the device is not sensitive to the operation wavelength and structure paraimeters.We hold that the novel controllable polarizatiou beam splitt.er has wide potential application in the PICs.