  Temporal cavity solitons (CSs) are persisting pulses of light that can
manifest themselves in continuously driven passive resonators, such as
macroscopic fiber ring cavities and monolithic microresonators. Experiments so
far have demonstrated two techniques for their excitation, yet both possess
drawbacks in the form of system complexity or lack of control over soliton
positioning. Here we experimentally demonstrate a new CS writing scheme that
alleviates these deficiencies. Specifically, we show that temporal CSs can be
excited at arbitrary positions through direct phase modulation of the cavity
driving field, and that this technique also allows existing CSs to be
selectively erased. Our results constitute the first experimental demonstration
of temporal cavity soliton excitation via direct phase modulation, as well as
their selective erasure (by any means). These advances reduce the complexity of
CS excitation and could lead to controlled pulse generation in monolithic
microresonators.
