In order to decrease the size of the device and realize ultrafast response time and dynamic tunable, single–band and dual–band plasmon induced transparency (PIT) effect are investigated based on graphene nanoribbon waveguide side–coupled with rectangle cavities system. The slow light properties of the model?are?numerically?and?theoretically analyzed by coupled mode theory and finite difference time domain method. With controlling the chemical potential of the graphene rectangle cavity, the?tunability of the resonant wavelength and the transmission peak can be?achieved simultaneously in single–band and dual–band PIT?model. As the chemical potential of graphene increases, the resonant wavelength of each transmission window of PIT effect is gradually decreased and blue shifted. In addition, through dynamically tuning the resonant wavelength of the graphene rectangle cavity, when the chemical potential of the graphene rectangle cavity is increased from 0.41 eV to 0.44 eV, the group index of single PIT system is controlled between 79.2 and 28.3, and the tunable bandwidth is 477 nm. Moreover, the group index of dual PIT system is controlled between 143.2 and 108.6 when the chemical potentials of graphene rectangle cavities 1, 2, and 3 are 0.39 eV to 0.42 eV, 0.40 eV to 0.43 eV, and 0.41 eV to 0.44 eV, respectively. The size of the entire PIT structure is 0.5 μm2. Research results are of reference significance in design and fabrication of optical sensors, optical filters, slow light and light storage devices with ultrafast, ultracompact and dynamic tunable.
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