An improved integrated optical device (5a-5g) is disclosed containing
first and second devices (10a-10g; 15a, 15e), optically coupled to each
other and formed in first and second different material systems. One of
the first or second devices (10a-10g, 15a, 15e) has a Quantum Well
Intermixed (QWI) region (20a, 20g) at or adjacent a coupling region
between the first and second devices (10a-10g; 15a, 15e). The first
material system may be a III-V semiconductor based on Gallium Arsenide
(GaAs) or Indium Phosphide (InP), while the second material may be Silica
(SiO.sub.2), Silicon (Si), Lithium Niobate (LiNbO.sub.3), a polymer, or
glass.