An optical control element is disclosed that can be made small and has a
low loss, and is able to provide group speed control and wavelength
dispersion of short light pulses. The optical control element is formed
from a photonic crystal, and includes a first portion having a first
refraction index in the photonic crystal, a second portion having a
second refraction index lower than the first refraction index, and a
refraction-index-distributed type defect wave guide. A difference
effective refraction indexes between the first portion and the second
portion near the refraction-index-distributed type defect wave guide,
changing continuously or stepwise along a wave guiding direction of the
refraction-index-distributed type defect wave guide.