A semiconductor structure and a method for fabricating the same are provided. The semiconductor structure includes a wafer substrate having a top surface and a bottom surface, and a conductive pillar in the wafer substrate defined by a deep trench insulator through the top surface and the bottom surface of the wafer substrate. The method for fabricating the semiconductor structure includes following steps. A deep trench is formed from a top surface of a wafer substrate to define a conductive region in the wafer substrate. The conductive region is doped with a dopant. The deep trench is filled with an insulation material to form a deep trench insulator. And the wafer substrate is thinned from a bottom surface of the wafer substrate to expose the deep trench insulator and isolate the conductive region to form a conductive pillar.

An optoelectronic circuit for producing an optical clock signal that includes an optical thyristor, a waveguide structure and control circuitry. The waveguide structure is configured to split an optical pulse produced by the optical thyristor such that a first portion of such optical pulse is output as part of the optical clock signal and a second portion of such optical pulse is guided back to the optical thyristor to produce another optical pulse that is output as part of the optical clock signal. The control circuitry is operably coupled to terminals of the optical thyristor and receives first and second control signal inputs. The control circuitry is configured to selectively decrease frequency of the optical clock signal based on the first control signal input and to selectively increase frequency of the optical clock signal based on the second control signal input.

The present disclosure relates to a photodetector device. The photodetector device includes a semiconductor substrate including a semiconductor material. An absorption region is disposed within the semiconductor substrate. The absorption region includes an epitaxial material that is different than the semiconductor material. A multiplication region is disposed within the semiconductor substrate and separated from the absorption region. A channel region is disposed between the multiplication region and the absorption region, where the channel region and the multiplication region meet at a p-n junction.