Waveguide-type optical resonators

A discussion is given of the optical resonators in which waveguide-type oscillation modes are excited. A classification of these modes is given. The high selectivity of the waveguide resonators is stressed. It is also mentioned that they are not sensitive to thermooptic effects resulting from pumping. Experimental results are quoted in support of the high coherence of the oscillations in waveguide resonators in the presence of strong deformations in the active medium.