Abstract: An array of photon counting phototoreceivers is constructed as an imager with micro-digitized pixels. Each photoreciever comprises a vertical cavity optical amplifier (VCSOA) as an optical amplifier, an avalanche photodiode as detector and an analog-to-digital converter (ADC) in an integrated structure. The ADC serves as a 1-bit digitizer and uses a resonant tunneling bipolar transistor RTBT. While the preferred embodiment of the invention have been described, it will be apparent to those skilled in the art that various modifications may be made to the embodiments without departing from the spirit of the present invention. Such modifications are all within the scope of the present invention.

Abstract: A vertical cavity semiconductor optical photoamplifer (VCSOA) is used as a modulating retro-reflector (MRR) as a pixel in an array. The boundary of the cavity in the VCSOA forms a mirror for reflecting an incident light as an amplified output.

Abstract: Alternate layers of wide band gap and narrow band gaps of different kinds of semiconductors are used to form multiple channels of a FET. The channels are doped or formed as 2-DEG/2-DHG in narrow band semiconductor by charge supply layer in the wide band gap semiconductor. The different kinds of semiconductors form heterojunctions to confine the electrons/holes in separate thin spikes layers. A number of spikes (3-10 nm thick) of different doped or 2-DEG/2-DHG concentrations in various channels can result in overall electron concentration gradient such as a 1/x3 electron/hole concentrations profile. Such an electron/hole concentration gradient can result in a linear variation of drain current with voltage to obtain a wide dynamic range.

Abstract: Alternate layers of wide band gap and narrow band gaps of different kinds of semiconductors are used to form multiple channels of a FET. The channels are doped or formed as 2-DEG/2-DHG in narrow band semiconductor by charge supply layer in the wide band gap semiconductor. The different kinds of semiconductors form heterojunctions to confine the electrons/holes in separate thin spikes layers. A number of spikes (3–10 nm thick) of different doped or 2-DEG/2-DHG concentrations in various channels can result in overall electron concentration gradient such as a 1/x3 electron/hole concentrations profile. Such an electron/hole concentration gradient can result in a linear variation of drain current with voltage to obtain a wide dynamic range.

Abstract: This invention describes an approach for monolithically integrating all the components of a photoreceiver—optical amplifier, optical band-pass filter, and photodiode module—on a single chip. The photoreceiver array employs unique optical amplifier and conversion technologies that provides the ultra-sensitivity required for free space optical communications networks. As an example, by monolithically integrating a vertical cavity surface emitting laser-diode (VCSEL) optical preamplifier with a photodiode receiver and related amplifiers and filters on the same chip, sensitivities as low as ?47 dBm (62 photons/bit at 2.5 Gb/s), along with an order of magnitude reduction in size, weight, and power consumption over comparable commercial-off-the-shelf (COTS) components can be demonstrated.

Abstract: Alternate layers of wide band gap and narrow band gaps of different kinds of semiconductors are used to form multiple channels of a FET. The channels are doped or formed as 2-DEG/2-DHG in narrow band semiconductor by charge supply layer in the wide band gap semiconductor. The different kinds of semiconductors form heterojunctions to confine the electrons/holes in separate thin spikes layers. A number of spikes (3-10 nm thick) of different doped or 2-DEG/2-DHG concentrations in various channels can result in overall electron concentration gradient such as a 1/x3electron/hole concentrations profile. Such an electron/hole concentration gradient can result in a linear variation of drain current with voltage to obtain a wide dynamic range.