Fabry-Perot microcavities with controllable resonant wavelengths in periodic dielectric waveguides

Fabry-Perot microcavities with controllable resonant wavelengths and constant quality factors are constructed by introducing defects in periodic dielectric waveguides. Two-dimensional finite-difference time-domain method is used to simulate the field distributions in the cavities. The simulated electric field profile fits a cosine-Gaussian curve. The quadratic relation between the resonant wavelength and the defect length is theoretically discussed and numerically proved. Simulations show that the resonant wavelength can be simply controlled by shifting cylinders in the defects, and the value of quality factor keeps a constant of about 10(3). (C) 2008 American Institute of Physics.