The reflectivity of absorbing Bragg reflectors consisting of a GaAs/AlAs Br
agg mirror and a InGaAs/InGaAsP multiple-quantum-well cavity layer was stud
ied as a function of temperature. An absorption dip in the stop band due to
the optical confinement of the Fabry-Perot resonance was observed in the r
eflectivity spectra. The absorption intensity of the dip increased with tem
perature and was explained by the resonant coincidence of the Fabry-Perot c
avity mode and the quantum-well absorption. The temperature-dependent refle
ctivity spectra were successfully reproduced using the transfer matrix meth
od and the linear dependence of the refractive index on temperature. (C) 20
01 Optical Society of America.