A monolithic semiconductor imager includes an indium-based III-V compound semiconductor monolithic active layer of a first conductivity type, an array of plural focal plane cells on the active layer, each of the focal plane cells including a photogate over a top surface of the active layer, a readout circuit dedicated to the focal plane cell including plural transistors formed monolithically with the monolithic active layer and a single-stage charge coupled device formed monolithically with the active layer between the photogate and the readout circuit for transferring photo-generated charge accumulated beneath the photogate during an integration period to the readout circuit. The photogate includes thin epitaxial semiconductor layer of a second conductivity type overlying the active layer and an aperture electrode overlying a peripheral portion of the thin epitaxial semiconductor layer, the aperture electrode being connectable to a photogate bias voltage.

/pdf/monolithic-in-based-iii-v-compound-semiconductor-focal-plane-1cypzzd4gn.pdf

Monolithic in-based III-V compound semiconductor focal plane array cell with single stage CCD output

An optical preamplifier includes a semiconductor optical amplifier monolithically integrated with an optical detector and electrically isolated from the detector by an isolation region. The isolation region consists of a low-loss, preferably transparent, insulating material whose index of refraction is matched to at least the refractive index of the amplifier, leading to reduced facet reflectivity at the amplifier output facet. Alternative device structures may include a waveguiding layer in the isolation region, a grating integrated with or following the optical amplifier, and a tuning region positioned between the amplifier and isolation region for filtering spontaneous emission.

Monolithically integrated semiconductor optical preamplifier

A method of improving the signal-to-noise ratio (dynamic range) in integrated optical spectrum analyzers. An integrated optical spectrum analyzer is formed with a lithium niobate (LiNbO3) substrate in its usual manner. Ions such as argon or hydrogen are implanted in the bottom and sides of the LiNbO3 which causes the substrate to absorb light at the wavelength of interest. The ion-implanted bottom and sides provide absorption with very little reflectivity and the amount of absorption is proportional to the effect of the ion and the time period of implantation. The bottom and sides behave as optical sinks, rather than as reflection or scattering centers.

Application of ion implantation to LiNbO3 integrated, optical spectrum analyzers

The combination, which is for optical communication systems, is constructed from a carrier substrate (1) of n-conducting semiconductor material, e.g. InP, a further layer (11), which is grown thereupon, is of the same material and in whose surface a strip-shaped n-conducting absorption layer (3) extends, and a waveguide (2) situated thereupon. A p-doping is diffused into the waveguide above the n-conducting absorption layer (3), resulting in the formation of a photodiode. The contact for the positive electrode (6) is applied over the p-conducting region, the contact for the negative electrode (5) is applied on the free side of the carrier substrate (1), and the waveguide (2) is covered above by a top layer (7).

Integrated monolithic waveguide-photodiode combination

A detector for counting low levels of photons comprises a plurality of thin solid state wafers of a photons sensitive material such as gallium arsenide; the wafers being of the order of one-tenth to two millimeter thick depending upon use, and providing a depletion layer of 2 to 20 millimeters deep depending upon the energy of the photons to be detected. The electrical length of the wafer depends upon the use for which the panel is designed and may be one-tenth to two millimeters if two dimensional analysis is desired. Some of the wafers depending upon their materials have a region beyond the 2 to 20 millimeter depth in which is formed an integrated circuit including a detector, preamplifier, discriminator, scaler and read out buffer, each responsive to a different multiplexed, digitized address word. The wafers are connected as PIN diodes and are properly biased for such function. Those wafers using materials on which IC cannot be formed are connected to ICs by leads.

Photon counting structure and system

There is disclosed an integrated optical detector comprising a semiconductor substrate having an optical waveguide formed integrally therewith and a photodetector made from the same semiconductor material as the waveguide and integrally coupled to it. The detector region is sensitive to light of the same wavelengths that can be transmitted through the waveguide region of the semiconductor without excessive absorption therein by virtue of the fact that after the waveguide is formed proton bombardment of the detector portion thereof is used to create optically active defect centers thereby shifting the effective absorption edge in the detector region. Where gallium arsenide is used as the semiconductor defect levels induced by implantation of high energy protons give rise to optical absorption between 6 micron and 0.9 micron. This results in detector action in the presence of a Schottkey barrier depletion layer. Detector response times less than 200 nanoseconds and external quantum efficiencies of 16 percent have been observed in the device.

Gregory L. Tangonan

Papers

Integrated optical detector

Method of making an integrated optical detector