# US 11,309,960 B2 · Measuring linear and non-linear transmission perturbations in optical transmission systems

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- Number: US 11,309,960 B2
- Document ID: US11309960B2
- Status: Granted
- Kind: B2
- Application number: 16/915,653
- Filed: 2020-06-29
- Published: 2020-12-31
- Granted: 2022-04-19
- Earliest claimed: 2019-06-27
- Assignees: Viavi Solutions Inc.
- Applicants: Viavi Solutions Inc.
- Inventors: Axel Flettner; Eberhard Lothar Loecklin; Wolfgang Moench
- Web page: https://patentgrep.com/patent/US11309960B2

## CPC

- H04B 10/07953: {Monitoring or measuring OSNR, BER or Q}
- H04B 10/07955: {Monitoring or measuring power}
- H04B 10/2543: due to fibre non-linearities, e.g. Kerr effect
- H04J 14/0227: {Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation}
- G01M 11/30: {Testing of optical devices, constituted by fibre optics or optical waveguides}
- H04B 10/07: Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B 10/40: Transceivers
- 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)
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR

## Abstract

A system for measuring linear and non-linear transmission perturbations in optical transmission systems is disclosed. The system may include a processor to help facilitate measurement of non-linear noise at an optical transceiver. The system, for example, may receive a reference correlation of a transmission of a channel of a fiber link, record an optical power spectrum of the channel, and determine a baud rate of the channel. The system may also apply a spectral correlation technique to the channel with a multiple baud rate distance in frequency domain. The system may also calculate a generalized optical signal-to-noise ratio (gOSNR) value based on the spectral correlation technique and the reference correlation. The system may also compare the gOSNR with wavelength division multiplexed (WDM) OSNR measurements to evaluate an amount of non-linear noise contributions.

## Claims

### Claim 1

A test instrument, comprising:
a processor;
a memory, which when executed by the processor, measures non-linear noise at an optical transceiver, as follows:
receive a reference correlation of a transmission of a channel of a fiber link;
record an optical power spectrum of the channel;
determine a baud rate of the channel;
apply a spectral correlation technique to the channel with a multiple baud rate distance in frequency domain;
calculate a generalized optical signal-to-noise ratio (gOSNR) value based on the spectral correlation technique and the reference correlation; and
compare the gOSNR with wavelength division multiplexed (WDM) OSNR measurements to evaluate an amount of non-linear noise contributions.

### Claim 2 (depends on 1)

The test instrument of claim 1, wherein the reference correlation is a value received from a third party system or a link operator.

### Claim 3 (depends on 1)

The test instrument of claim 1, wherein the optical power spectrum of the channel is recorded from a point of interest on the fiber link.

### Claim 4 (depends on 1)

The test instrument of claim 1, wherein the baud rate of the channel is determined based on at least one of a scan, estimate, or calculation.

### Claim 5 (depends on 1)

The test instrument of claim 1, wherein the baud rate of the channel is 32 GBaud for a 100 Gbit PM-QPSK.

### Claim 6 (depends on 1)

The test instrument of claim 1, wherein the spectral correlation technique comprises probing two frequency components of the channel.

### Claim 7

A method, comprising:
receiving, by a processor, a reference correlation of a transmission of a channel of a fiber link;
recording an optical power spectrum of the channel;
determining a baud rate of the channel;
applying a spectral correlation technique to the channel with a multiple baud rate distance in frequency domain;
calculating a generalized optical signal-to-noise ratio (gOSNR) value based on the spectral correlation technique and the reference correlation; and
comparing the gOSNR with wavelength division multiplexed (WDM) OSNR measurements to evaluate an amount of non-linear noise contributions.

### Claim 8 (depends on 7)

The method of claim 7, wherein the reference correlation is a value received from a third party system or a link operator.

### Claim 9 (depends on 7)

The method of claim 7, wherein the optical power spectrum of the channel s recorded from a point of interest on the fiber link.

### Claim 10 (depends on 7)

The method of claim 7, wherein the baud rate of the channel is determined based on at least one of a scan, estimate, or calculation.

### Claim 11 (depends on 7)

The method of claim 7, wherein the baud rate of the channel is 32 GBaud for a 100 Gbit PM-QPSK.

### Claim 12 (depends on 7)

The method of claim 7, wherein the spectral correlation technique comprises probing two frequency components of the channel.

### Claim 13

A non-transitory computer-readable storage medium having an executable stored thereon, which when executed instructs a processor to perform the following:
receive a reference correlation of a transmission of a channel of a fiber link;
record an optical power spectrum of the channel;
determining a baud rate of the channel;
applying a spectral correlation technique to the channel with a multiple baud rate distance in frequency domain;
calculating a generalized optical signal-to-noise ratio (gOSNR) value based on the spectral correlation technique and the reference correlation; and
comparing the gOSNR with wavelength division multiplexed (WDM) OSNR measurements to evaluate an amount of non-linear noise contributions.

### Claim 14 (depends on 13)

The non-transitory computer-readable storage medium of claim 13, wherein the reference correlation is a value received from a third party system or a link operator.

### Claim 15 (depends on 13)

The non-transitory computer-readable storage medium of claim 13, wherein the optical power spectrum of the channel is recorded from a point of interest on the fiber link.

### Claim 16 (depends on 13)

The non-transitory computer-readable storage medium of claim 13, wherein the baud rate of the channel is determined based on at least one of a scan, estimate, or calculation.

### Claim 17 (depends on 13)

The non-transitory computer-readable storage medium of claim 13, wherein the baud rate of the channel is 32 GBaud for a 100 Gbit PM-QPSK.

### Claim 18 (depends on 13)

The non-transitory computer-readable storage medium of claim 13, wherein the spectral correlation technique comprises probing two frequency components of the channel.