  As an important device for detecting rotation, high sensitivity gyroscope is
required for practical applications. In recent years, exceptional point (EP)
shows its potential in enhancing the sensitivity of sensing in optical cavity.
Here we propose an EP enhanced optical gyroscope based on mechanical
PT-symmetric system in microcavity. By pumping the two optical modes with
different colors, i.e. blue and red detuning, an effective mechanical
PT-symmetric system can be obtained and the system can be prepared in EP with
appropriate parameters. Compared with the situation of diabolic point, EP can
enhance the sensitivity of gyroscope with more than one order of magnitude in
the weak perturbation regime. The results show the gyroscope can be enhanced
effectively by monitoring mechanical modes rather than optical modes. Our work
provides a promising approach to design gyroscope with higher sensitivity in
optical microcavity and has potential values in some fields including
fundamental physic and precision measurement.
