Rare earth-doped fiber amplifier with integral optical metrology functionality

Patent metadata

Field	Value
Publication number	US-9503181-B2
Application number	US-201514590460-A
Country	US
Kind code	B2
Filing date	Jan 6, 2015
Priority date	Jan 6, 2015
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A doped fiber amplifier (e.g., an erbium-doped fiber amplifier—EDFA) module is configured to include metrology functionality for performing real-time measurements of the fiber spans connected to the EDFA. In one embodiment, a separate component utilized to perform optical time domain reflectometry (OTDR) measurements is embedded with the EDFA module. The OTDR measurement component includes its own laser source and detector, which are used to analyze the input and output fiber spans associated with the EDFA. In another embodiment, the pump laser of the EDFA is also used as the optical probe light source for the OTDR component, where the source is either “switched” or “shared” between performing amplification and providing OTDR measurements. In yet another embodiment, a “dual pump” source is included with the OTDR component itself and modified to utilize one laser for amplification and the other for OTDR purposes.

First claim

What is claimed is:

1. An optical device coupled to an input fiber span at an input port and an output fiber span at an output port, the device comprising
a doped fiber amplifier component including
a section of doped optical fiber;
a first coupling element for receiving an incoming optical communication signal propagating along the input fiber span and inserting the optical communication signal into the section of doped fiber;
a second coupling element for receiving an optical pump signal and inserting the optical pump signal into the section of doped fiber; and
a third coupling element disposed at the output of the doped fiber amplifier for receiving an amplified version of the optical communication signal and inserting the amplified optical communication signal into the output fiber span; and

an optical metrology arrangement coupled to one or more of the first, second and third coupling elements of the doped fiber amplifier, the optical metrology arrangement including
an optical laser source for generating optical probe light at a predetermined wavelength and introducing the generated optical probe light along either one or both of the input fiber span, via the first coupling element, and the output fiber span, via the third coupling element; and
a photoreceiver for accepting reflected probe light and measuring the reflected optical power in a manner that is utilized to determine physical properties and optical characteristics of the associated optical fiber span.

2. An optical device as defined in claim 1 wherein
the doped fiber amplifier includes a laser source for generating the optical pump signal at a predetermined pump wavelength λ pump , and coupling the optical pump signal into the section of doped fiber via the second coupling element; and
the optical metrology arrangement includes
an optical source for generating optical probe light operating at a wavelength λ test separate and distinct from λ pump , the probe light utilized to perform optical time domain reflectometry (OTDR) measurements for either one or both of the input fiber span and the output fiber span;
a photoreceiver for accepting return reflected light created along a measured fiber span; and
an optical coupling arrangement for directing created probe light toward the measured fiber span and directing return reflected light into the photoreceiver for analysis and generation of fiber span characteristics from the OTDR measurements.

3. The optical device as defined in claim 2 wherein the optical metrology arrangement is coupled to a single one of the input and output fiber spans.

4. The optical device as defined in claim 2 wherein the optical metrology arrangement is coupled to both of the input fiber span and the output fiber span.

5. The optical device as defined in claim 4 wherein the optical metrology arrangement comprises a first metrology unit coupled to the input fiber span and a second metrology unit coupled to the output fiber span, each metrology unit including its own optical source, photoreceiver and optical coupling arrangement.

6. The optical device as defined in claim 4 wherein the optical metrology arrangement comprises a single metrology unit coupled to both the input fiber span and the output fiber span.

7. The optical device as defined in claim 6 wherein the optical metrology arrangement is coupled to the input and output fiber spans by an included optical switch, wherein the optical switch is operated to send the probe light into the input fiber span when the switch is in a first position and to send the probe light into the output fiber span when the switch is in a second position.

8. The optical device as defined in claim 7 wherein the optical switch includes a third output position that terminates the propagation of the probe light to discontinue the OTDR measurement process.

9. The optical device as defined in claim 6 wherein the optical metrology arrangement is coupled to the input and output fiber spans by an included optical power splitter, such that a first probe output is directed into the input fiber span and a second probe output is directed into the output fiber span.

10. The optical device as defined in claim 1 wherein the optical laser source of the optical metrology arrangement further comprises a tunable laser source for introducing a range of wavelengths into either one or both of the input and output fiber spans so as to collect additional information used to determine a chromatic dispersion characteristic of the measured fiber span.

11. The optical device of claim 1 wherein the doped fiber amplifier component and the optical metrology arrangement share the optical laser source disposed within the optical metrology arrangement, wherein
the doped fiber amplifier includes an optical pump light path for introducing pump light into the second coupling element; and
the optical laser source of the optical metrology arrangement generates optical pump light at the predetermined pump wavelength λ pump , the optical pump light thereafter passing through a coupling arrangement and injected into the optical pump light path of the doped fiber amplifier, the optical laser source further comprising an arrangement for coupling the optical output as probe light into either one or both of the input and output fiber spans to perform optical measurements therealong.

12. The optical device of claim 11 wherein the optical metrology arrangement further comprises an optical switch for receiving the optical pump light output of the optical laser source, the optical switch including a set of three output ports and controlled so as to provide the optical pump light to a selected one of the input fiber span, the doped fiber amplifier, and the output fiber span.

13. The optical device of claim 11 wherein the optical metrology arrangement further comprises an optical splitter for receiving the optical pump light output of the optical laser source, the optical switch including a set of three output ports and utilized to divide the optical pump signal into a set of three separate output pump signals, with a separate one coupled to each one of the input fiber span, the doped fiber amplifier, and the output fiber span.

14. The optical device of claim 1 wherein the doped fiber amplifier component and the optical metrology arrangement share the optical laser source disposed within the optical metrology arrangement, wherein
the doped fiber amplifier includes an optical pump light path for introducing pump light into the second coupling element; and
the optical laser source of the optical metrology arrangement comprises a first laser diode for generating the optical pump light at the predetermined pump wavelength λ pump , the optical pump light thereafter passing through a coupling arrangement and inserted into the optical pump light path of the doped fiber amplifier, the laser source further comprising a second laser diode for generating an optical probe test light output at a predetermined test wavelength λ test and coupling the optical probe test light into either one or both of the input and output fiber spans to perform optical measurements therealong.

15. The optical device as defined in claim 14 wherein the second laser diode of the laser source is coupled to the input and output fiber spans by an included optical switch, wherein the optical switch is operated to send the probe test light into the input fiber span when the switch is in a first position and to send the probe test light into the output fiber span when the switch is in a second position.

16. The optical device as defined in cla

Assignees

• Ii Vi Inc

Inventors

• Mcclean Ian Peter
• Gurusami Aravanan

Classifications

• H04B10/071 Primary

  using a reflected signal, e.g. using optical time domain reflectometers [OTDR] · CPC title

• H04B10/07955 Primary

  Monitoring or measuring power · CPC title

• H04B10/503

  Laser transmitters · CPC title

• G01M11/3154

  Details of the opto-mechanical connection, e.g. connector or repeater · CPC title

• H04B10/2912

  characterised by the medium used for amplification or processing · CPC title