Abstract 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.
An integrated optical detector circuit comprising: a. substrate having a semiconductor optical waveguide formed integrally therewith; and b. photodetector made from semiconductor material having the same active atomic composition as that of said waveguide and integrally coupled to said waveguide, said photodetector comprising as active portion of said waveguide material having optically active defect centers therein which shift the absorption edge therein to a wavelength different from that of the rest of said waveguide material, and an ohmic contact made to one surface and a rectifying contact made to the opposite surface of said active portion whereby optical energy which is transmitted through said waveguide can be sensed as a photocurrent flowing across said rectifying contact through said active absorption edge shifted portion of said waveguide, said device thereby eliminating coupling energy losses between said waveguide and said photodetector.
Claim 2
Dependent Claim
139 words
An integrated optical detector circuit comprising: a. substrate having a semiconductor optical waveguide formed integrally therewith; and b. photodetector made from semiconductor material having the same active atomic composition as that of said waveguide and integrally coupled to said waveguide, said photodetector comprising as active portion of said waveguide material having optically active defect centers therein which shift the absorption edge therein to a wavelength different from that of the rest of said waveguide material, and an ohmic contact made to one surface and a rectifying contact made to the opposite surface of said active portion whereby optical energy which is transmitted through said waveguide can be sensed as a photocurrent flowing across said rectifying contact through said active absorption edge shifted portion of said waveguide, said device thereby eliminating coupling energy losses between said waveguide and said photodetector.
Claim 3
Dependent Claim
45 words
A device as in claim 1 wherein after said waveguide is formed said photodetector active portion of said waveguide material is formed by proton bombardment of said region to create said optically active defect centers therein to thereby shift the effective wavelength absorption edge therein.
Claim 4
Dependent Claim
79 words
A device as in claim 1 wherein said semiconductor substrate having said optical waveguide formed integrally therewith is doped gallium arsenide and wherein said active photodetector portion of said waveguide has optically active defect centers therein formed by proton bombardment thereof to shift the effective wavelength absorption edge from a wavelength of approximately 0.9 micron in said waveguide to approximately 6 micron in said photodetector and wherein said rectifying contact is a metal film forming a Schottkey type barrier.
Claim 5
Dependent Claim
20 words
A device as in claim 3 wherein said metal film forming said Schottkey barrier is a transparent thin gold film.
Claim 6
Dependent Claim
18 words
A device as in claim 3 wherein said metal film forming said Schottkey barrier is an aluminum film.