Coherent Optical Receiver

Patent metadata

Field	Value
Publication number	US-2016182155-A1
Application number	US-201414578756-A
Country	US
Kind code	A1
Filing date	Dec 22, 2014
Priority date	Dec 22, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A coherent optical receiver that receives an optical PSK-modulated signal includes optical elements that combine the optical PSK-modulated signal and an optical local-oscillating (LO) signal and splits the combined optical signals into multiple parts that have a predefined phase offset relative to one another. The receiver further includes at least one thyristor and control circuitry operably coupled to terminals of the at least one thyristor. The control circuitry is configured to receive the multiple parts of the combined optical signals and controls switching operation of the at least one thyristor according to phase offset of optical PSK-modulated signal relative to the optical LO signal.

First claim

What is claimed is:

1 . A coherent optical receiver that receives an optical PSK-modulated signal comprising:
optical elements that combine the optical PSK-modulated signal and an optical local-oscillating (LO) signal and splits the combined optical signals into multiple parts that have a predefined phase offset relative to one another; at least one thyristor; and control circuitry operably coupled to terminals of the at least one thyristor, wherein the control circuitry is configured to receive the multiple parts of the combined optical signals and controls switching operation of the at least one thyristor according to phase offset of optical PSK-modulated signal relative to the optical LO signal.

2 . A coherent optical receiver according to claim 1 , wherein:
said at least one thyristor produces a digital electrical signal output according to phase offset of the optical PSK-modulated signal relative to the optical LO signal.

3 . A coherent optical receiver according to claim 1 , wherein:
said at least one thyristor produces a digital optical signal output according to phase offset of optical PSK-modulated signal relative to the optical LO signal.

4 . A coherent optical receiver according to claim 1 , wherein:
said at least one thyristor is defined by an epitaxial layer structure that includes a bottom n-type cathode region, an intermediate p-type region formed above the bottom n-type region, an intermediate n-type region formed above the intermediate p-type region, and a top p-type anode region formed above the intermediate n-type region, wherein each optical thyristor includes an anode terminal electrically coupled to the top p-type anode region, an n-type injector terminal electrically coupled to the intermediate n-type region, a p-type injector terminal electrically coupled to the intermediate p-type region, and a cathode terminal electrically coupled to the n-type cathode region.

5 . A coherent optical receiver according to claim 4 , wherein:
said control circuitry includes first, second, third and fourth phototransistors associated with a given thyristor; wherein said first and second phototransistors are each configured to receive respective parts of the combined optical signals that are offset in phase by π/2 radians with respect to one another, wherein said first phototransistor is electrically coupled to the p-type injector terminal of the given thyristor, and wherein said second phototransistor is electrically coupled to the n-type injector terminal of the given thyristor; and wherein said third and fourth phototransistors each configured to receive other respective parts of the combined optical signals that are offset in phase by π/2 radians with respect to one another, wherein said third phototransistor is electrically coupled to the p-type injector terminal of the given thyristor, and wherein said fourth phototransistor is electrically coupled to the n-type injector terminal of the given thyristor.

6 . A coherent optical receiver according to claim 5 , wherein:
said first and fourth phototransistors are configured as turn-on phototransistors that operate the given thyristor in its ON state for a particular first phase offset of the optical PSK-modulated signal relative to the optical LO signal, wherein said first phototransistor supplies hole current to the p-type injector terminal in order to operate the given thyristor in its ON state, and wherein said fourth phototransistor supplies electron current to the n-type injector terminal in order to operate the given thyristor in its ON state.

7 . A coherent optical receiver according to claim 5 , wherein:
said second and third phototransistors are configured as turn-off phototransistors that operate the given thyristor in its OFF state for a particular second phase offset of the optical PSK-modulated signal relative to the optical LO signal, wherein said second phototransistor draws hole current from the p-type injector terminal in order to operate the given thyristor in its OFF state, and wherein said third phototransistor draws electron current from the n-type injector terminal in order to operate the given thyristor in its OFF state.

8 . A coherent optical receiver according to claim 5 , wherein:
said first phototransistor is a p-channel HFET phototransistor whose source-drain current path is electrically coupled between a positive voltage supply and the p-type injector terminal of the given thyristor; said second phototransistor is a p-channel HFET phototransistor whose source-drain current path is electrically coupled between a positive voltage supply and the n-type injector terminal of the given thyristor; said third phototransistor is an n-channel HFET phototransistor whose source-drain current path is electrically coupled between a negative or ground voltage supply and the p-type injector terminal of the given thyristor; said fourth phototransistor is an n-channel HFET phototransistor whose source-drain current path is electrically coupled between a negative or ground voltage supply and the n-type injector terminal of the given thyristor.

9 . A coherent optical receiver according to claim 5 , wherein:
said optical elements include a first waveguide coupler configured to split the combined optical signals into two parts that are supplied to both said first and second phototransistors, respectively; and said optical elements include a second waveguide coupler configured to split the combined optical signals into two parts that are supplied to both said third and fourth phototransistors, respectively.

10 . A coherent optical receiver according to claim 4 , wherein:
the intermediate n-type and p-type regions of the epitaxial layer structure of the thyristor include an n-type modulation doped QW structure and a p-type modulation doped QW structure, respectively.

11 . A coherent optical receiver according to claim 10 , wherein:
said control circuitry includes at least one phototransistor that includes an n-type QW channel formed by the n-type modulation doped QW structure of the epitaxial layer structure.

12 . A coherent optical receiver according to claim 10 , wherein:
said control circuitry includes at least one phototransistor that includes a p-type QW channel formed by the p-type modulation doped QW structure of the epitaxial layer structure.

13 . A coherent optical receiver according to claim 4 , wherein:
the epitaxial layer structure comprises group III-V materials.

14 . A coherent optical receiver according to claim 1 , wherein:
the optical PSK-modulated signal employs binary phases; and said at least one thyristor and control circuitry comprise a thyristor and associated control circuit that controls switching action of the thyristor to produce a digital output signal that corresponds to the detected binary phase of the optical PSK-modulated signal.

15 . A coherent optical receiver according to claim 1 , wherein:
the optical PSK-modulated signal employs a plurality of phases greater than two; and said at least one thyristor and control circuitry comprise a plurality of thyristors and associated control circuits that controls switching action of the plurality of thyristors to produce a plurality of digital output signals that correspond to the detected phase of the optical PSK-modulated signal.

16 . A coherent optical receiver according to claim 15 , further comprising:
at least one optical XOR circuit for processing digital output signals produced by the plurality of thyristors for deriving digital signals that represent the detected phase of the optical PSK

Assignees

• Opel Solar Inc
• Univ Connecticut

Inventors

• Taylor Geoff W
• Zhang Yan

Classifications

• H04B10/615

  Arrangements affecting the optical part of the receiver · CPC title

• H04B10/613 Primary

  including phase diversity, e.g., having in-phase and quadrature branches, as in QPSK coherent receivers · CPC title

• H04B10/63

  Homodyne {, i.e. coherent receivers where the local oscillator is locked in frequency and phase to the carrier signal} · CPC title

• H10D64/233

  Cathode or anode electrodes for thyristors · CPC title

• H10D18/00

  Thyristors · CPC title