The control of the group delay and group delay dispersion in the design of
chirped mirror is difficult. To reduce this difficult it is important to adopt what is
so called impedance matching design. This paper presents a design of quart wave
mirror which includes the impedance matching. The design is divided into two
stages. In the first stage a quarter waves stack to provide high reflectivity of
over a bandwidth of the design and within certain limits is considered.
The control on average group delay depends upon wavelengths that are function of
penetration depth. However, the group delay as a function of wavelength shows
periodic variations due to the impedance mismatch between the ambient medium
and the mirror surface and its layers. In the second stage of the design tapered
Bragg stack over a wavelength range (600-1100nm) is adopted as a single chirp.