# US 9,235,100 B1 · Apparatus for dual-polarization QAM and optical communications system using the same cross-reference to related application

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- Number: US 9,235,100 B1
- Document ID: US9235100B1
- Status: Granted
- Kind: B1
- Application number: 13/602,282
- Filed: 2012-09-03
- Granted: 2016-01-12
- Earliest claimed: 2007-02-27
- Assignees: CeLight, Inc.
- Applicants: Arkady Kaplan
- Inventors: Arkady Kaplan
- Web page: https://patentgrep.com/patent/US9235100B1

## CPC

- G02F 1/225: in an optical waveguide structure
- B01D 43/00: Separating particles from liquids, or liquids from solids, otherwise than by sedimentation or filtration (flotation processes B03D1/00; drying solid materials or objects F26B)
- H04B 10/2543: due to fibre non-linearities, e.g. Kerr effect
- H04B 10/505: {using external modulation}
- H04B 10/5053: {using a parallel, i.e. shunt, combination of modulators}
- H04B 10/5057: {using a feedback signal generated by analysing the optical output}
- H04B 10/50577: {to control the phase of the modulating signal}
- H04B 10/508: Pulse generation, e.g. generation of solitons
- H04B 10/532: Polarisation modulation
- H04B 10/541: {Digital intensity or amplitude modulation}
- H04B 10/5561: {Digital phase modulation}
- H04B 10/60: Receivers
- H04J 14/005: {Optical Code Multiplex}
- H04J 14/08: Time-division multiplex systems
- H04L 7/0075: {with photonic or optical means}
- B01D 57/02: by electrophoresis (treatment of water, waste water, sewage or sludge by electrophoresis C02F1/469; electrophoretic production of compounds or non-metals C25B7/00; investigating or analysing materials by using electrophoresis G01N27/26)
- G02F 2201/126: push-pull
- G02F 2203/06: Polarisation independent
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- H04B: TRANSMISSION
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

An integrated optical signal Synthesizer and Analyzer for optical communications, each formed on a single chip, is disclosed. The Synthesizer and Analyzer are both design to use a Dual-Polarization Quadrature Amplitude Modulation (QAM) for communication operating at high data rates. A communication system for data transmission having such synthesizer and the analyzer is also disclosed.

## Claims

### Claim 1

An integrated transmitting synthesizer for optical communication, generating an optical signal modulated between multiple phase states and between different states of polarization, comprising:
a Y-branch dividing the light beam from a light source and producing a first and a second transmitting beams; the first and the second transmitting beams entering a first M-PSK modulator and a second M-PSK modulator, respectively, and producing a first and a second PSK-modulated output beams; a first and a second polarization controllers receiving the first and the second output modulated beams, respectively, and creating a third and a fourth beams having polarization state orthogonal to each other; wherein the third and the fourth beams are modulated between multiple phase states and between different states of polarization and form an output of the synthesizer, wherein the first M-PSK-modulated beam is reflected from a first mirror prior to entering the first MZ modulator, and the second MPSK-modulated beam is reflected from a second mirror prior to entering the second MZ modulator, and wherein the first and the second mirrors located on the back output surface of a planar chip; the first MZ modulator producing the first QAM-beam and the second MZ modulator producing the second QAM-beam; the first QAM-beam is reflected from a third mirror prior to entering the polarization combiner, and the second QAM-beam is reflected from a fourth mirror prior to entering the polarization combiner, wherein the third and fourth mirrors located on the front surface of the planar chip, the first, the second, the third and the fourth mirrors providing compactness critical to the synthesizer formation on the single chip; the polarization combiner outputting a dual-polarization QAM signal.

### Claim 2 (depends on 1)

The optical device of claim 1, wherein the Y-branch, the two M-PSK modulators, the first and a second polarization controllers, the two MZ modulators and the first, the second, the third and the fourth mirrors and the polarization combiner are formed as a part of a single planar chip.

### Claim 3 (depends on 1)

The optical device of claim 1, wherein the chip is made of a material selected from ferroelectric or semiconductor material.

### Claim 4 (depends on 1)

The optical device of claim 1, wherein a technology is used with an electro-optical material selected from in-diffused metal technology, protonic-exchange optical technology, etching optical technology or optical technology.

### Claim 5 (depends on 1)

The optical device of claim 1, wherein the light source is a laser source producing a continuous light signal.

### Claim 6

An integrated receiving apparatus for optical communication, receiving a transmitted optical signal modulated between multiple amplitude states, multiple phase states and between two states of polarization of the optical beam, comprising:
a first waveguide receiving a first optical input beam; the first optical input beam being a first transmitted S optical beam modulated between multiple phase states and between different states of polarization;
a second waveguide receiving a second optical input beam; the second Lo optical input beam being a Local Oscillator polarized at 45 degrees relatively to the TE and TM polarizations of the waveguide;
a first splitter dividing the first optical input beam into a third and a fourth optical beams;
a second splitter dividing the second optical input beam into a fifth and a sixth optical beams;
a first phase-shifter, applied to the third optical beam; the first phase-shifter affecting the TE optical mode exclusively, within the third optical beam;
a second phase-shifter, applied to the fourth optical beam; the second phase-shifter affecting the TM optical mode exclusively, within the fourth optical beam;
a first 3 dB coupler, mixing the third optical beam and the fifth optical beam; the first 3 dB coupler, outputting a seventh and an eighth optical beams;
a second 3 dB coupler, mixing the fourth optical beam and the sixth optical beam; the second 3 dB coupler, outputting a ninth and a tenth optical beams;
a first polarization splitter; the first polarization splitter having the seventh optical beam as an input and producing a first output of TE polarization and a second output of TM polarization;
a second polarization splitter; the second polarization splitter having the eighth optical beam as an input and producing a third output of TE polarization and a fourth output of TM polarization;
a third polarization splitter; the third polarization splitter having the ninth optical beam as an input and producing a fifth output of TE polarization and a sixth output of TM polarization;
a fourth polarization splitter; the fourth polarization splitter having the tenth optical beam as an input and producing a seventh output of TE polarization and an eighth output of TM polarization;
a first balance detector, detecting the first output of TE polarization and the third output of TE polarization;
a second balance detector, detecting the second output of TM polarization and the fourth output of TM polarization;
a third balance detector, detecting the fifth output of TE polarization and the seventh output of TE polarization;
a fourth balance detector, detecting the sixth output of TM polarization and the eighth output of TM polarization;
the first balance detector and the third balance detector being used to recover a transmitted data in TE polarization;
the second balance detector and the fourth balance detector being used to recover a transmitted data in TM polarization.

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein the first splitter, the second splitter, the first phaseshifter, the second phase-shifter, the first 3 dB coupler, the second 3 dB coupler, the first polarization splitter, the second polarization splitter, the third polarization splitter, the fourth polarization splitter, the first balance detector, the second balance detector, the third balance detector, the fourth balance detector are formed as a part of a single planar chip.

### Claim 8 (depends on 6)

The apparatus of claim 6, wherein the chip is made of a material selected from ferroelectric or semiconductor or glass material.

### Claim 9 (depends on 6)

The apparatus of claim 6, wherein a technology is used with the electro-optical material is selected from in-diffused metal technology, protonic-exchange optical technology, etching optical technology or milling technology.

### Claim 10

An optical communication system for data transmission, comprising: a synthesizer transmitting an encoded optical beam to a receiver, the synthesizer comprising: Y-branch dividing the light beam from the light source and producing a first and a second transmitting beams; the first and the second transmitting beams entering a first M-PSK modulator and a second M-PSK modulator producing a first and a second PSK-modulated output beams; a first and a second polarization controllers receiving the first and the second output modulated beams, respectively, and creating a third and a fourth beams having polarization state orthogonal to each other; the first PSK-modulated beam is reflected from a first mirror prior to entering the first MZ modulator, and the second PSK-modulated beam is reflected from a second mirror prior to entering the second MZ modulator, wherein the first and the second mirrors located on the back output surface of a planar chip; the first MZ modulator producing the first QAM-beam and the second MZ modulator producing the second QAM-beam; the first QAM-beam is reflected from a third mirror prior to entering the polarization combiner, and the second QAM-beam is reflected from a fourth mirror prior to entering the polarization combiner, wherein the third and fourth mirrors located on the front surface of the planar chip, the first, the second, the third and the fourth mirrors providing compactness critical to the synthesizer formation on the single chip; the polarization combiner outputting a dual-polarization QAM signal; the synthesizer formed as a part of a single planar chip.

### Claim 11 (depends on 10)

The optical communication system of claim 10, wherein the receiver is a coherent optical analyzer comprising:
a first waveguide receiving a first optical input beam; the first optical input beam being the first transmitted S optical beam modulated between multiple phase states and between different states of polarization;
a second waveguide receiving a second Lo optical input beam; the second Lo optical input beam being a Local Oscillator polarized at 45 degrees relatively to the TE and TM polarizations of the waveguide;
a first splitter dividing the first optical input beam into a third and a fourth optical beams;
a second splitter dividing the second optical input beam into a fifth and a sixth optical beams;
a first phase-shifter, applied to the third optical beam; the first phase-shifter affecting the TE optical mode exclusively, within the third optical beam;
a second phase-shifter, applied to the fourth optical beam; the second phase-shifter affecting the TM optical mode exclusively, within the fourth optical beam;
a first 3 dB coupler, mixing the third optical beam and the fifth optical beam; the first 3 dB coupler, outputting a seventh and a eighth optical beams;
a second 3 dB coupler, mixing the fourth optical beam and the sixth optical beam; the second 3 dB coupler, outputting a ninth and a tenth optical beams;
a first polarization splitter; the first polarization splitter having seventh optical beam as an input and producing a first output of TE polarization and a second output of TM polarization;
a second polarization splitter; the second polarization splitter having eighth optical beam as an input and producing a third output of TE polarization and a fourth output of TM polarization;
a third polarization splitter; the third polarization splitter having ninth optical beam as an input and producing a fifth output of TE polarization and a sixth output of TM polarization;
a fourth polarization splitter; the fourth polarization splitter having tenth optical beam as an input and producing a seventh output of TE polarization and a eighth output of TM polarization;
a first balance detector, detecting the first output of TE polarization and the third output of TE polarization;
a second balance detector, detecting the second output of TM polarization and the fourth output of TM polarization;
a third balance detector, detecting the fifth output of TE polarization and the seventh output of TE polarization;
a fourth balance detector, detecting the sixth output of TM polarization and the eighth output of TM polarization;
the first balance detector and the third balance detector being used to recover a transmitted data in TE polarization;
the second balance detector and the fourth balance detector being used to recover a transmitted data in TM polarization; wherein
the analyzer formed as a part of a single planar chip.

### Claim 12 (depends on 11)

The optical communication system of claim 11, wherein the data transmission is performed in fiber.

### Claim 13 (depends on 11)

The optical communication system of claim 11, wherein the data transmission is performed in free space or between satellites.

### Claim 14 (depends on 11)

The optical communication system of claim 11, wherein the data is transmitted using dual-polarization star-QAM modulation format.

### Claim 15 (depends on 11)

The optical communication system of claim 11, wherein the data rate is at least 40 Gb/s.

### Claim 16 (depends on 11)

The optical communication system of claim 11, wherein the data transmission is in long haul communications system more than 1000 km long.

### Claim 17 (depends on 11)

The optical communication system of claim 11, wherein the data transmission is in metropolitan area.