Abstract: The present invention relates to a monolithic integrated demultiplexing photoreceiver that is formed on a semi-insulating InP substrate. A frequency routing device is formed on the substrate and includes a first plurality of In/InGaAs semiconductor layers. At least one p-i-n photodiode is also formed on the substrate and includes a second plurality of InP/InGaAs semiconductor layers. Additionally, at least one single heterostructure bipolar transistor is formed on the substrate and includes a third plurality of InP/InGaAs semiconductor layers. At least one layer from each of the first, second and third plurality of layers are substantially identical to one another.

Abstract: A monolithically integrated laser which is rapidly tunable over a wide optical frequency range comprises a frequency router formed in a semiconductive wafer defining a tuned cavity. A control circuit applies electrical energy to predetermined controllably transmissive waveguides connecting the frequency routing device with reflective elements defined in the wafer. This tunes the laser to a desired one of a plurality of optical frequencies. Application of such electrical energy creates frequency selective pathways through the wafer able to support selected lasing frequencies. This laser is economical to construct and is useful in high capacity, high speed optical communications networks.

Abstract: A method for reducing birefringence in a silicate waveguide structure having a waveguide core and cladding includes the step of selecting an irradiation energy that induces compaction in the cladding. The waveguide structure is then irradiated with radiation having an energy equal to the irradiation energy to induce a reduction in birefringence.