An integrated demultiplexer/photoreceiver (IDP) for optical networks and optical
interconnection devices has a common substrate which supports three sequentially
arranged basic components: a waveguide grating router, an array of photodetectors,
and an array of heterojunction transistors. Basic layers of all three components
are grown together in a common epitaxial process, and then each of the components
is individually patterned in accordance with its function. Such structure of IDP
makes it possible to reduce the cost, simplify the design, improve conditions for
optical alignment, and reduce optical losses. In accordance with one embodiment
of the invention, transparency of the optical signal transmission layer of the
WGR is controlled by selectively doping the layers of the multiple-layer waveguide
structure, while in another embodiment such control is achieved by changing the
width of the energy gap in the optical signal transmission layer of the WGR. Such
a change is achieved by utilizing electrical bias and optical pumping from an external
light source operating on a predetermined wavelength. The invention also provides
a method for controlling transparency of the layer that transmits optical signals
through the waveguide units in optoelectronic devices, such as an integrated demultiplexer/photoreceiver
for optical network, by utilizing optical pumping and electrical bias.