The nonlinear Fabry-Perot interferometer is a basic building block of photomechanical polymer optical fiber devices. In this work, we will the analyze the nonlinear Fabry-Perot interferometer from a theoretical and numerical perspective to gain insight into its multi-stability and nonlinear hysteretic behavior. We will also extend the device design by incorporating a variety of Bragg grating geometries. The Bragg gratings allow tuning of both wavelength and reflectance and can be leveraged to build complex interconnected photomechanical device networks.