# US 12,113,577 B2 · Method and system for encoding multi-level pulse amplitude modulated signals using integrated optoelectronic devices

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- Number: US 12,113,577 B2
- Document ID: US12113577B2
- Status: Granted
- Kind: B2
- Application number: 17/453,408
- Filed: 2021-11-03
- Published: 2022-08-04
- Granted: 2024-10-08
- Earliest claimed: 2008-09-08
- Assignees: Cisco Technology, Inc.
- Applicants: Cisco Technology, Inc.
- Inventors: Daniel Kucharski; Sherif Abdalla; Brian Welch
- Web page: https://patentgrep.com/patent/US12113577B2

## CPC

- H04B 10/5161: {Combination of different modulation schemes}
- G02B 26/06: for controlling the phase of light (G02B26/08 takes precedence {, measuring optical phase difference G01J9/00})
- G02F 1/0121: {Operation of devices; Circuit arrangements, not otherwise provided for in this subclass}
- G02F 1/225: in an optical waveguide structure
- G02F 1/2255: {controlled by a high-frequency electromagnetic component in an electric waveguide structure}
- H04B 10/0795: {Performance monitoring; Measurement of transmission parameters}
- H04B 10/505: {using external modulation}
- H04B 10/5053: {using a parallel, i.e. shunt, combination of modulators}
- H04B 10/541: {Digital intensity or amplitude modulation}
- G02B 26/0841: {the reflecting element being moved or deformed by electrostatic means}
- G02F 1/212: {Mach-Zehnder type}
- G02F 2201/58: Arrangements comprising a monitoring photodetector
- H04B: TRANSMISSION
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- 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

## Abstract

Methods and systems for encoding multi-level pulse amplitude modulated signals using integrated optoelectronics are disclosed and may include generating a multi-level, amplitude-modulated optical signal utilizing an optical modulator driven by first and second electrical input signals, where the optical modulator may configure levels in the multi-level amplitude modulated optical signal, drivers are coupled to the optical modulator; and the first and second electrical input signals may be synchronized before being communicated to the drivers. The optical modulator may include optical modulator elements coupled in series and configured into groups. The number of optical modular elements and groups may configure the number of levels in the multi-level amplitude modulated optical signal. Unit drivers may be coupled to each of the groups. The electrical input signals may be synchronized before communicating them to the unit drivers utilizing flip-flops. Phase addition may be synchronized utilizing one or more electrical delay lines.

## Claims

### Claim 1

A system for processing signals, the system comprising:
a plurality of flip-flops arranged to synchronize electrical input signals;
a plurality of drivers arranged to drive the synchronized electrical input signals from the plurality of flip-flops;
a first optical modulator comprising a first set of unit drivers arranged to drive a first plurality of diodes based on the synchronized electrical input signals from the plurality of drivers; and
a second optical modulator comprising a second set of unit drivers arranged to drive a second plurality of diodes based on the synchronized electrical input signals from the plurality of drivers, wherein the first set of unit drivers has more unit drivers than the second set of unit drivers, and wherein the first and second optical modulators are arranged to generate a multi-level, amplitude-modulated optical signal based on the synchronized electrical input signals from the plurality of drivers.

### Claim 2 (depends on 1)

The system of claim 1, further comprising one or more multiplexers arranged to select the electrical input signals.

### Claim 3 (depends on 2)

The system of claim 2, wherein the one or more multiplexers are arranged to select between an electrical input or a complement of the electrical input.

### Claim 4 (depends on 1)

The system of claim 1, further comprising one or more delay lines used to synchronize phase addition in a plurality of optical modulator elements in the first optical modulator.

### Claim 5 (depends on 1)

The system of claim 1, wherein the first optical modulator is integrated on a single substrate.

### Claim 6 (depends on 5)

The system of claim 5, wherein the single substrate comprises one of: silicon, gallium arsenide, germanium, indium gallium arsenide, indium phosphide, or polymer-based materials.

### Claim 7 (depends on 1)

The system of claim 1, wherein the first optical modulator comprises a Mach-Zehnder interferometer.

### Claim 8 (depends on 1)

The system of claim 1, wherein the first optical modulator comprises one or more ring modulators.