Graphene-Assisted Polarization-Insensitive Electro-absorption Optical Modulator

We report on a polarization-insensitive optical modulator architecture comprised of silica/Si/hBN/graphene/hBN/graphene/hBN/Si stack upon a silica substrate to support transverse electric (TE) and transversemagnetic (TM) polarizing modes with identical absorption. The identical absorption between TE and TM modes is strict condition for realizing polarization-insensitive electro-absorption optical modulator. This in turn entails significant compromise in polarization-sensitivity loss. The horizontal arm of active region of waveguide support TE mode while TM mode is supported by vertical arm ensuring polarization-sensitive loss of < 1 dB. The model is capable of offering extinction ratio of 18.87 dB, insertion loss of 2.32 dB and figure-of-merit of 8.14 for TE mode. Concurrently, for TM mode are 19.39 dB, 2.41 dB and 8.04. The operating wavelength of modulator ranges from similar to 1500 to similar to 1590 nm with optical bandwidth excess of 90 nm. The 3-dB modulation bandwidth of 62.74 GHz is realized with active length of 12 mu m long at the expense of 1.28 fJ/bit ensuring the polarization-sensitive loss at ON-State of 0.1 dB and tolerance between TE and TM modes of 0.82 dB.