Optical heterodyne receiver for fiber optic communications system
AssigneeSpire Corporation
InventorH. Paul Maruska
Life of this patent
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Abstract
A monolithic integrated optical heterodyne receiver circuit formed on a single chip and a process of its manufacture are disclosed. The heterodyne receiver circuit essentially includes a tunable local oscillator formed on a substrate for generating a first light beam, a first waveguide coplanarly formed on the substrate adjacent to the local oscillator for transmitting the first light beam, a second waveguide formed on top of the first waveguide for receiving and transmitting an information-encoded second light beam, a coupler region sandwiched between the first and second waveguides for mixing the two light beams, and a pair of detectors mounted in electrical series with one another for converting the mixed light beams to a radio frequency signal operating at an intermediate frequency.
Claims12
An integrated optical heterodyne receiver circuit formed on a single chip and comprised of:
- (a) a substrate;
- (b) a local oscillator formed on said substrate for generating a first light beam;
- (c) a first waveguide for transmitting said first light beam;
- (d) a second waveguide formed on top of said first waveguide for receiving and transmitting an information-encoded second light beam;
- (e) a coupler region sandwiched between said first and second waveguides for mixing said first and second light beams;
- and
- (f) a pair of detectors mounted adjacent to said first and second waveguides for converting said mixed light beams to an intermediate frequency signal;
- (g) said pair of detectors being coupled in electrical series with one another;
- (h) said intermediate frequency signal being obtainable at a function between said pair of detectors.
The integrated circuit of claim i wherein said first waveguide is coplanarly formed on said substrate adjacent to said local oscillator, and wherein said pair of detectors abut said coupler region at a point where each of said first and second light beams has undergone about a 50% transfer into its adjacent waveguide.
A process of forming an integrated optical heterodyne receiver circuit on a single chip comprised of:
- (a) providing a substrate;
- (b) successively depositing on said substrate materials for integrally forming a local oscillator, a first waveguide and a lower detector therein;
- and
- (c) forming on a portion of said first materials, while masking the remaining portion, a directional coupler region, second waveguide and an upper detector;
- (d) said detectors being formed in tandem, one above the other, and provided with a ledge access for electrical contact.
Dependencies are inferred from the claim text.