An apparatus is provided to compensate for dispersion in a transmission
medium. The apparatus includes an input port for receiving a WDM optical
signal having a plurality of signal wavelengths and a first Bragg
transmission grating receiving the WDM optical signal from the input port.
The first Bragg transmission grating has non-zero dispersion at at least
one of the signal wavelengths. The first Bragg transmission grating also
has a Bragg wavelength that is chosen so that all of the plurality of
signal wavelengths lie outside of a reflection band of the first Bragg
transmission grating. A second Bragg transmission grating, which is
optically coupled to the first Bragg transmission grating, has a non-zero
dispersion at at least one of the signal wavelengths. The second Bragg
transmission grating also has a Bragg wavelength that is selected so that
all of the plurality of signal wavelengths lie outside of a reflection
band of the second Bragg transmission grating. Finally, an output port is
provided for receiving the optical signal from the second Bragg grating
and communicating the optical signal to an external source.