  We report on our observation of thermal control of transmission spectra of a
micro-ring resonator coupled to a low finesse etalon. Thermal tuning of the
device changes the coupling strength and losses between the etalon and ring
resonator resulting in a wide variety of line shapes ranging from a symmetric
to asymmetric Fano-like to electromagnetically induced transparency (EIT)-like
behavior. The capability to modify spectral line shapes by thermally tuning the
coupling strength and losses between two resonators has obvious applications in
optical communication networks and relevance to sensor applications where it
may be exploited for developing novel cutoff switches and has significant,
deleterious effect on measurement uncertainties of large dynamic range sensors.
