  Optical circuit switching is connection-oriented, being deterministic through
the reservation of a complete wavelength channel or spatial path for a certain
period. However, this comes at a trade-off against link dynamics, and overall
capacity can thus be constrained by the time slot reservations, especially for
switches with microsecond- to millisecond-scale reconfiguration times. For
data-intensive applications, the communication patterns associated with random
data sets typically yield short-lived flows. This situation calls for a new
multi-dimensional switching paradigm that fully exploits not only the space and
wavelength domains but also with nanosecond-scale reconfigurable capability in
the time domain to enable ultra-dynamic links. In this work, we focus on the
exploitation of micro-ring resonant phase shifters (RPSs) that are wavelength
selective for optical switching in a single plane. By proposing an innovative
analytical method with transmission circle chart, we fully unlock the power of
RPS with nanosecond-scale reconfigurability and the capability to arbitrarily
manipulate its phase and amplitude. Such a compact model offers fresh insights
into designs with under and critically coupled RPSs beyond the commonly
explored over-coupling condition. This creates not only versatile switch
elements but also perfect absorbers for robust multi-wavelength operations. The
proposed device can bring about a breakthrough in the optical switching
capacity that potentially addresses the challenges faced by modern data center
networks, as well as other photonic circuits for high-throughput signal
processing.
