This paper describes a new approach to the design of multi-element resonant reflectors. These mirrors provide an effective means of controlling the spectral spread of high-gain laser oscillators, but the complexity of the reflectivity as a function of wavelength

has made the design of these systems rather difficult. However, we show that by making a two-dimensional plot of reflectivity versus wavelength and temperature, one can obtain several parameters of the system immediately that an

plot does not reveal. Simple algebraic expressions for some of these parameters are given, and a configuration for an improved four-element wavelength selector based on these results is presented.