  We report the role of $\mathcal{PT}$-symmetry in switching characteristics of
a highly nonlinear fiber Bragg grating (FBG) with cubic-quintic-septic
nonlinearities. We demonstrate that the device shows novel bi-(multi-) stable
states in the broken regime as a direct consequence of the shift in the
photonic band gap influenced by both $\mathcal{PT}$-symmetry and higher-order
nonlinearities. We also numerically depict that such FBGs provide a productive
test bed where the broken $\mathcal{PT}$-symmetric regime can be exploited to
set up all-optical applications such as binary switches, multi-level signal
processing and optical computing. Unlike optical bistability (OB) in the
traditional and unbroken $\mathcal{PT}$-symmetric FBG, it exhibits many
peculiar features such as flat-top stable states and ramp like input-output
characteristics before the onset of OB phenomenon in the broken regime. The
gain/loss parameter plays a dual role in controlling the switching intensities
between the stable states which is facilitated by reversing the direction of
light incidence. We also find that the gain/loss parameter tailors the
formation of gap solitons pertaining to transmission resonances which clearly
indicates that it can be employed to set up optical storage devices. Moreover,
the interplay between gain/loss and higher order nonlinearities brings notable
changes in the nonlinear reflection spectra of the system under constant pump
powers. The influence of each control parameters on the switching operation is
also presented in a nutshell to validate that FBG offers more degrees of
freedom in controlling light with light.
