Optoelectronic circuit employing a heterojunction thyristor device to convert a digital optical signal to a digital electrical signal
View Patent ↗An optoelectronic circuit includes a resonant cavity formed on a substrate and into which is injected an input digital optical signal that encodes bits of information (each bit representing an OFF logic level or an ON logic level). A heterojunction thyristor device, formed in the resonant cavity, produces an output digital electrical signal corresponding to the input digital optical signal. A sampling clock defines sampling periods that overlap the bits (e.g., ON/OFF pulse durations) in the input digital optical signal. The sampling clock can be in the form of electrical pulses supplied to the n-channel injector terminal(s) and/or p-channel injector terminals of the heterojunction thyristor device. Alternatively, the sampling clock can be in the form of optical pulses that are part of the Optical IN signal that is resonantly absorbed by the device. The heterojunction thyristor device operates in an OFF state and an ON state. In the OFF state, current does not flow between an anode terminal and a cathode terminal of the device; while in the ON state, current flows between the anode terminal and the cathode terminal. To provide optical-to-electrical conversion of the digital bit stream, the heterojunction thyristor device switches from its OFF state to its ON state in the event that, during a given sampling period, the light intensity level of the input digital optical signal corresponds to the ON logic level; however, it does not switch into the ON state (and remains in the OFF state) in the event that, during the given sampling period, the light intensity level of the digital optical signal corresponds to the OFF logic level.
1. An integrated circuit comprising:
a) a substrate;
b) a thyristor device formed on said substrate, said thyristor device having at least one modulation doped quantum well structure that defines a channel region, an anode terminal electrode, a cathode terminal electrode, and at least one control terminal electrode that is operably coupled to said modulation doped quantum well structure; and
c) at least one current source means, operably coupled to said control terminal electrode, for drawing charge from said channel region.
2. An integrated circuit according to claim 1 , wherein:
said thyristor device operates in an OFF state and an ON state, wherein current does not flow between said anode terminal electrode and said cathode terminal electrode in said OFF state, and wherein current flows between said anode terminal electrode and said cathode terminal electrode in said ON state.
3. An integrated circuit according to claim 1 , wherein:
said modulation doped quantum well structure comprises an n-type modulation doped layer spaced apart from at least one quantum well by an undoped spacer layer.
4. An integrated circuit according to claim 1 , wherein:
said modulation doped quantum well structure comprises a p-type modulation doped layer spaced apart from at least one quantum well by an undoped spacer layer.
5. An integrated circuit according to claim 1 , wherein:
said modulation doped quantum well structure comprises an n-type modulation doped quantum well structure and a p-type modulation doped structure, said n-type modulation doped quantum well structure comprises an n-type modulation doped layer spaced apart from at least one quantum well by an undoped spacer layer, and said p-type modulation doped quantum well structure comprises an p-type modulation doped layer spaced apart from at least one quantum well by an undoped spacer layer.
6. An integrated circuit according to claim 2 , further comprising:
a bias network coupled to said cathode terminal that defines magnitude of current conducting from the cathode terminal in the ON state.
7. An integrated circuit according to claim 1 , wherein:
said thyristor device is formed from a multilayer structure of group III-V materials.
8. An integrated circuit according to claim 1 , wherein:
said thyristor device further comprises a p-channel FET transistor formed on said substrate and an n-channel FET transistor formed atop said p-channel FET transistor.
9. An integrated circuit according to claim 8 , wherein:
said p-channel FET transistor comprises a p-type modulation doped quantum well structure, and said n-channel FET transistor comprises an n-type modulation doped quantum well structure.
10. An integrated circuit according to claim 9 , wherein:
said p-channel FET transistor includes a bottom active layer operably coupled to said cathode terminal,
said n-channel FET transistor includes a top active layer operably coupled to said anode terminal, and
said control terminal electrode of said thyristor device is operably coupled to one of said n-type modulation doped n-type quantum well structure and said p-type modulation doped quantum well structure.
11. An integrated circuit according to claim 10 , wherein:
said thyristor device further comprises an ohmic contact layer, a metal layer for said anode terminal that is formed on said ohmic contact layer, and a plurality of p-type layers formed between said ohmic contact layer and said n-type modulation doped quantum well structure.
12. An integrated circuit according to claim 1 , further comprising:
a plurality of said thyristor devices formed on said substrate.