  Quantum Zeno and anti-Zeno effects in an asymmetric nonlinear optical coupler
are studied. The asymmetric nonlinear optical coupler is composed of a linear
waveguide ($\chi^{\left(1\right)}$) and a nonlinear waveguide
($\chi^{\left(2\right)}$) interacting with each other through the evanescent
waves. The nonlinear waveguide has quadratic nonlinearity and it operates under
second harmonic generation. A completely quantum mechanical description is used
to describe the system. The closed form analytic solutions of Heisenberg's
equations of motion for the different field modes are obtained using Sen-Mandal
perturbative approach. In the coupler, the linear waveguide acts as a probe on
the system (nonlinear waveguide). The effect of the presence of the probe
(linear waveguide) on the photon statistics of the second harmonic mode of the
system is considered as quantum Zeno and anti-Zeno effects. Further,it is also
shown that in the stimulated case, it is easy to switch between quantum Zeno
and anti-Zeno effects just by controlling the phase of the second harmonic mode
of the asymmetric coupler
