# US 8,786,843 B2 · Testing of passive optical components

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- Number: US 8,786,843 B2
- Document ID: US8786843B2
- Status: Granted
- Kind: B2
- Application number: 13/411,866
- Filed: 2012-03-05
- Published: 2013-09-05
- Granted: 2014-07-22
- Earliest claimed: 2012-03-05
- Assignees: Verizon Patent and Licensing Inc.
- Applicants: David Zhi Chen
- Inventors: David Zhi Chen
- Web page: https://patentgrep.com/patent/US8786843B2

## CPC

- G01M 11/335: {using two or more input wavelengths}
- G01M 11/337: {by measuring polarization dependent loss [PDL]}
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR

## Abstract

Methods and devices provide for transmitting a series of optical signals within a range of an O-band through a U-band into a device under test comprising one or more passive optical components; measuring powers of the optical signals that propagated through the device under test; calculating wavelength-dependent insertion loss values based on the measured power of the optical signals; measuring powers of reflected portions of the optical signals that propagated through the device under test; and calculating wavelength-dependent return loss values based on the measured powers of the reflected portion of the optical signal.

## Claims

### Claim 1

A method comprising:
setting a state of polarization of an optical signal;
setting a first initial state of polarization of the optical signal that propagates through a device under test;
setting a second initial state of polarization of a reflected portion of the optical signal that propagates through the device under test;
transmitting the optical signal, via a test system, into the device under test comprising one or more passive optical components;
measuring a power of the optical signal that propagated through the device under test;
calculating a wavelength-dependent insertion loss based on the measured power of the optical signal;
measuring another power of the reflected portion of the optical signal that propagated through the device under test; and
calculating a wavelength-dependent return loss based on the other measured power of the reflected portion of the optical signal.

### Claim 2 (depends on 1)

The method of claim 1, wherein the transmitting comprises:
transmitting the optical signal for an O-band through a U-band.

### Claim 3 (depends on 1)

The method of claim 1,
wherein test components of the test system are optically connected to each other and the device under test using a single mode optical fiber.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
rotating the state of polarization, from the initial state of polarization to an end state of polarization, of the optical signal;
rotating the state of polarization, from the initial state of polarization to an end state of polarization, of the reflected portion of the optical signal;
measuring power values, of the optical signal and the reflected portion of the optical signal, during the rotating;
selecting minimum and maximum power values associated with the optical signal and the reflected portion of the optical signal; and
calculating a wavelength-dependent polarization loss based on the selected minimum and maximum power values.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
rotating the state of polarization, from the first initial state of polarization to an end state of polarization, of the optical signal;
rotating the state of polarization, from the second initial state of polarization to an end state of polarization, of the reflected portion of the optical signal;
measuring power values, of the optical signal and the reflected portion of the optical signal, during the rotating;
selecting maximum power values associated with the optical signal and the reflected portion of the optical signal; and
selecting a state of polarization that yields the maximum power values associated with the optical signal and the reflected portion of the optical signal.

### Claim 6 (depends on 5)

The method of claim 5, further comprising:
setting the state of polarization that yields a maximum power value associated with the optical signal;
setting the state of polarization that yields a maximum power value associated with the reflected portion of the optical signal;
setting a first mode to be filtered out of the optical signal;
setting a second mode to be filtered out of the reflected portion of the optical signal;
filtering out the first mode from the optical signal that propagated through the device under test;
filtering out the second mode from the reflected portion of the optical signal that propagated through the device under test.

### Claim 7 (depends on 5)

The method of claim 5, further comprising:
measuring power values, of the optical signal and the reflected portion of the optical signal, during the filtering out;
determining whether another mode is to be filtered out of the optical signal and the reflected portion of the optical signal; and
calculating a wavelength-dependent multi-path interference based on the measured power values obtained during the filtering out, in response to a determination that another mode is not to be filtered out of the optical signal and the reflected portion of the optical signal, wherein the test system includes a single-mode optical fiber.

### Claim 8 (depends on 1)

The method of claim 1, wherein the test system includes an environmental chamber;
setting one or more environmental values pertaining to the environmental chamber; and
exposing the device under test to one or more environmental conditions in correspondence to the one or more environmental values.

### Claim 9

A test system comprising:
a user device comprising:
a communication interface;
one or more memories that store instructions; and
one or more processors to execute the instructions to:
receive a selection of parameters directed to conducting a test of a device under test comprising one or more passive optical components;
cause, via the communication interface, other test components of the test system to conduct the test based on the parameters, the other test components comprising:
an optical signal source capable of transmitting an optical signal, which has a wavelength between an O-band through a U-band, through the device under test;
an optical receiver comprising a power meter that is optically connected to, and upstream from, the device under test; and
another optical receiver comprising a power meter that is optically connected to, and downstream from, the device under test;
collect, via the communication interface, test data during the test from the optical receiver and the other optical receiver;
calculate, wavelength-dependent insertion loss and wavelength-dependent return loss; and
store wavelength-dependent insertion loss and wavelength-dependent return loss values.

### Claim 10 (depends on 9)

The test system of claim 9, wherein, when causing, the one or more processors further execute the instructions to:
cause the optical signal source to transmit a series of optical signals, each having a unique wavelength between the O-band through the U-band, through the device under test.

### Claim 11 (depends on 9)

The test system of claim 9, wherein the other test components further comprise:
a first polarization controller that is optically connected to, and downstream from, the device under test;
a second polarization controller that is optically connected to, and upstream from, the device under test; and
a third polarization controller that is optically connected to, and downstream from, the device under test
wherein, when causing, the one or more processors further execute the instructions to:
cause the first polarization controller to set a state of polarization of the optical signal;
cause the second polarization controller to rotate the state of polarization of the optical signal; and
cause the third polarization controller to rotate the state of polarization of a reflected portion of the optical signal.

### Claim 12 (depends on 11)

The test system of claim 11, wherein, when calculating, the one or more processors further execute the instructions to:
calculate a wavelength-dependent polarization loss.

### Claim 13

The test system of claim of 9, wherein the other test components further comprising:
an optical phase mask that is optically connected to, and downstream from, the device under test; and
another optical phase mask that is optically connected to, and upstream from, the device under test;
wherein, when causing, the one or more processors further execute the instructions to:
cause the optical phase mask to filter a mode of the optical signal; and
cause the other optical phase mask to filter a mode of a reflected portion of the optical signal.

### Claim 14 (depends on 13)

The test system of claim 13, wherein, when calculating, the one or more processors further execute the instructions to:
calculate a wavelength-dependent multi-path interference based on a mode-filtered optical signal and a mode-filtered reflected portion of the optical signal.

### Claim 15 (depends on 9)

The test system of claim 9, wherein the test components are optically connected to each other and the device under test using a single mode optical fiber.

### Claim 16 (depends on 9)

The test system of claim 9, wherein the test components further comprise:
an optical splitter that is optically connected, upstream from, the device under test.

### Claim 17 (depends on 9)

The test system of claim 9, wherein the test components further comprise:
an optical filter that is capable of filtering a wavelength associated with the optical signal.

### Claim 18

A method comprising:
setting states of polarization of the optical signals;
transmitting a series of optical signals within a range of an O-band through a U-band, via a test system, into a device under test comprising one or more passive optical components;
rotating states of polarization of the optical signals that propagated through the device under test;
measuring powers of the optical signals that propagated through the device under test;
calculating wavelength-dependent insertion loss values based on the measured powers of the optical signals;
rotating states of polarization of reflected portions of the optical signals that propagated through the device under test;
measuring powers of the reflected portions of the optical signals that propagated through the device under test;
calculating wavelength-dependent return loss values based on the measured powers of the reflected portion of the optical signal; and
calculating wavelength-dependent polarization loss values.

### Claim 19 (depends on 18)

The method of claim 18, further comprising:
setting initial states of polarization of the optical signals that propagate through the device under test; and
setting initial states of polarization of the reflected portions of the optical signals that propagate through the device under test.

### Claim 20 (depends on 18)

The method of claim 18, further comprising:
setting a first mode to be filtered out of the optical signals;
setting a second mode to be filtered out of the reflected portion of the optical signals;
filtering out the first mode from the optical signals that propagated through the device under test;
filtering out the second mode from the reflected portion of the optical signals that propagated through the device under test; and
calculating wavelength-dependent multi-path interference values.

### Claim 21

A method comprising:
setting a first mode to be filtered out of optical signals;
setting a second mode to be filtered out of reflected portions of the optical signals;
transmitting a series of the optical signals within a range of an O-band through a U-band, via a test system, into a device under test comprising one or more passive optical components;
filtering out the first mode from the optical signals that propagated through the device under test;
measuring powers of the optical signals that propagated through the device under test;
calculating wavelength-dependent insertion loss values based on the measured powers of the optical signals;
filtering out the second mode from the reflected portions of the optical signals that propagated through the device under test;
measuring powers of the reflected portions of the optical signals that propagated through the device under test;
calculating wavelength-dependent return loss values based on the measured powers of the reflected portion of the optical signal; and
calculating wavelength-dependent multi-path interference values.