  Aluminum nitride has been shown to possess both strong Kerr nonlinearity and
electro-optic Pockels effect. By combining these two effects, here we
demonstrate on-chip reversible on/off switching of the optical frequency comb
generated by an aluminum nitride microring resonator. We optimize the design of
gating electrodes and the underneath resonator structure to effectively apply
electric field without increasing the optical loss. The switching of the comb
is monitored by measuring one of the frequency comb peaks while varying the
electric field. The controlled comb electro-optic response is investigated for
direct comparison with the transient thermal effect.
