An approach for compensating for losses in a tunable laser filter comprising
includes
providing a tunable waveguide material and an amplifying material that have different
compositions. The tuning material and the amplifying material are placed parallel
to one another. The amplifying material is disposed so that it covers the tuning
material at discrete locations. Carriers are injected simultaneously into both
materials. The tuning material is spaced from the amplifying material at an average
distance that is greater than the charge carrier diffusion length, so as to reduce
avoid diffusion of charge carriers from the tuning material into the amplifying
material. This prevents the amplifying material draining the charge carriers out
of the tuning material, thus enabling the refractive index of the tuning material
to be tuned for a desired wavelength effect.
