Abstract: Avalanche photodiodes (APDs) having at least one top stressor layer disposed on a germanium (Ge)-containing absorption layer are described herein. The top stressor layer can increase the tensile strain of the Ge-containing absorption layer, thus extending the absorption of APDs to longer wavelengths beyond 1550 nm. In one embodiment, the top stressor layer has a four-layer structure, including an amorphous silicon (Si) layer disposed on the Ge-containing absorption layer; a first silicon dioxide (SiO2) layer disposed on the amorphous Si layer, a silicon nitride (SiN) layer disposed on the first SiO2 layer, and a second SiO2 layer disposed on the SiN layer. The Ge-containing absorption layer can be further doped by p-type dopants. The doping concentration of p-type dopants is controlled such that a graded doping profile is formed within the Ge-containing absorption layer to decrease the dark currents in APDs.

Abstract: Avalanche photodiodes having special lateral doping concentration that reduces dark current without causing any loss of optical signals and method for the fabrication thereof are described. In one aspect, an avalanche photodiode comprises: a substrate, a first contact layer coupled to at least one metal contract of a first electrical polarity, an absorption layer, a doped electric control layer having a central region and a circumferential region surrounding the central region, a multiplication layer having a partially doped central region, and a second contract layer coupled to at least one metal contract of a second electrical polarity. Doping concentration in the central section of the electric control layer is lower than that of the circumferential region. The absorption layer can be formed by selective epitaxial growth.

Abstract: Avalanche photodiodes having special lateral doping concentration that reduces dark current without causing any loss of optical signals and method for the fabrication thereof are described. In one aspect, an avalanche photodiode comprises: a substrate, a first contact layer coupled to at least one metal contract of a first electrical polarity, an absorption layer, a doped electric control layer having a central region and a circumferential region surrounding the central region, a multiplication layer having a partially doped central region, and a second contract layer coupled to at least one metal contract of a second electrical polarity. Doping concentration in the central section of the electric control layer is lower than that of the circumferential region. The absorption layer can be formed by selective epitaxial growth.

Abstract: Various embodiments of a photonic device and fabrication method thereof are provided. In one aspect, a device includes a substrate, a current confinement layer disposed on the substrate, an absorption layer disposed in the current confinement layer, and an electrical contact layer disposed on the absorption layer. The current confinement layer is doped in a pattern and configured to reduce dark current in the device. The photonic device may be a photodiode or a laser.

Abstract: Avalanche photodiodes having special lateral doping concentration that reduces dark current without causing any loss of optical signals and method for the fabrication thereof are described. In one aspect, an avalanche photodiode comprises: a substrate, a first contact layer coupled to at least one metal contract of a first electrical polarity, an absorption layer, a doped electric control layer having a central region and a circumferential region surrounding the central region, a multiplication layer having a partially doped central region, and a second contract layer coupled to at least one metal contract of a second electrical polarity. Doping concentration in the central section is lower than that of the circumferential region. The absorption layer can be formed by selective epitaxial growth.

Abstract: Avalanche photodiodes (APDs) having at least one top stressor layer disposed on a germanium (Ge)-containing absorption layer are described herein. The top stressor layer can increase the tensile strain of the Ge-containing absorption layer, thus extending the absorption of APDs to longer wavelengths beyond 1550 nm. In one embodiment, the top stressor layer has a four-layer structure, including an amorphous silicon (Si) layer disposed on the Ge-containing absorption layer; a first silicon dioxide (SiO2) layer disposed on the amorphous Si layer, a silicon nitride (SiN) layer disposed on the first SiO2 layer, and a second SiO2 layer disposed on the SiN layer. The Ge-containing absorption layer can be further doped by p-type dopants. The doping concentration of p-type dopants is controlled such that a graded doping profile is formed within the Ge-containing absorption layer to decrease the dark currents in APDs.

Abstract: Various embodiments of a method and device for dark current cancellation for optical power monitoring in optical transceivers are presented. In one aspect, a device includes a photosensitive module and a processing module coupled to the photosensitive module. The photosensitive module is configured to detect an optical signal and generate a first signal responsive to detecting the optical signal. The processing module is configured to determine a value of a second signal that is related to noise and determine a value of a third signal that is related to a difference between a value of the first signal and the value of the second signal.

Abstract: Avalanche photodiodes having special lateral doping concentration that reduces dark current without causing any loss of optical signals and method for the fabrication thereof are described. In one aspect, an avalanche photodiode comprises: a substrate, a first contact layer coupled to at least one metal contract of a first electrical polarity, an absorption layer, a doped electric control layer having a central region and a circumferential region surrounding the central region, a multiplication layer having a partially doped central region, and a second contract layer coupled to at least one metal contract of a second electrical polarity. Doping concentration in the central section is lower than that of the circumferential region. The absorption layer can be formed by selective epitaxial growth.