  Photon splitting is a QED process that can potentially suppress pair
production in the inner magnetosphere of a pulsar with a super-strong magnetic
field, and hence, may quench radio emission from these objects. While it is
unknown how many splitting modes really operate in super-critical fields, we
derive gap parameters of a high magnetic field pulsar for both the vacuum-type
gap and the space-charge-limited flow accelerator under the assumption that all
three splitting modes permitted by QED operate. The competition between photon
splitting and pair production depends on the gap parameters, and the
``photon-splitting-dominant'' line for both cases are derived. We discuss the
implications of these results and the possible connection of the high magnetic
field pulsars with the anomalous X-ray pulsars and soft gamma-ray repeaters
which are conjectured to be magnetars.
