Secured fiber link system

• US 10,284,288 B2
• Filed: 02/17/2017
• Issued: 05/07/2019
• Est. Priority Date: 02/18/2016
• Status: Active Grant

• Current Assignee: Apriori Network Systems, LLC
• Original Assignee: Apriori Network Systems, LLC
• Inventors: Weiner, Gary M.
• Primary Examiner(s): Payne, David C
• Assistant Examiner(s): Barua, Pranesh K
• Application Number:
  US15/435,619
• Publication Number:
  US 20170244478A1
• Time in Patent Office: 809 Days
• Field of Search: 398 40, 380256, 380 33
• CPC Class Codes: H04B 10/85 Protection from unauthorised access, e.g. eavesdrop protection
• CPC Class Codes: H04L 69/00 Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass networks security protocols H04L9/40; wireless communication networks H04W

Abstract

A fiber link system, method and device for masking signals on a fiber link system. The system includes sending a desired sequence of information in the form of a true signal that is typically intended to be transferred between legitimate users at both ends of a link. Sending chaff signals, or subterfuge signals, alongside the true signal to mask such legitimate signals in the fiber cable from intruders tapping into the fiber cable.

Claims

1. A secured fiber link system, comprising:

a spatially multiplexing optical fiber;

a transmit spatial multiplexer configured to couple each of a plurality of optical signals into a respective one of a plurality of distinct spatial paths of the spatially multiplexing optical fiber, each of the spatial paths being able to carry an optical signal;

at least one optically modulated transmit source coupled to the transmit spatial multiplexer so that an optically modulated signal supplied as an output from the at least one optically modulated transmit source is coupled by the transmit spatial multiplexer into one of the plurality of spatial paths of the spatially multiplexing optical fiber;

at least one optically modulated chaff source coupled to the transmit spatial multiplexer so that each optically modulated chaff signal supplied as an output from the at least one optically modulated chaff source is coupled by the transmit spatial multiplexer into a respective one of the plurality of spatial paths of the spatially multiplexing optical fiber that are other than the spatial path to which the at least one optically modulated transmit source is coupled, wherein at least one of the at least one optically modulated chaff source occupies substantially a same optical frequency range as at least one of the at least one optically modulated transmit source; and

a receive spatial multiplexer configured to extract at least one spatial path from the spatially multiplexing fiber;

wherein an aggregate optical power of all the optically modulated chaff sources within the optical frequency range substantially occupied by the optically modulated transmit source is chosen such that a ratio of transmit signal power to optically modulated chaff signal power coupled out at a fiber bend made at any location along the fiber is smaller than a required signal-to-noise ratio specified by at least one of the at least one optically modulated transmit source'"'"'s corresponding receiver to achieve error-free performance at its output.

2. A secured fiber link system, comprising:

a spatially multiplexing optical fiber;

a transmit spatial multiplexer configured to couple each of a plurality of optical signals into a respective one of a plurality of distinct spatial paths of the spatially multiplexing optical fiber, each of the spatial paths being able to carry an optical signal;

at least one optically modulated transmit source coupled to the transmit spatial multiplexer so that an optically modulated signal supplied as an output from the at least one optically modulated transmit source is coupled by the transmit spatial multiplexer into one of the plurality of spatial paths of the spatially multiplexing optical fiber;

at least one optically modulated chaff source coupled to the transmit spatial multiplexer so that each optically modulated chaff signal supplied as an output from the at least one optically modulated chaff source is coupled by the transmit spatial multiplexer into a respective one of the plurality of spatial paths of the spatially multiplexing optical fiber that are other than the spatial path to which the at least one optically modulated transmit source is coupled, wherein at least one of the at least one optically modulated chaff source occupies substantially a same optical frequency range as at least one of the at least one optically modulated transmit source; and

a receive spatial multiplexer configured to extract at least one spatial path from the spatially multiplexing fiber;

wherein an optical power of at least one of the at least one optically modulated chaff source within the optical frequency range substantially occupied by an optically modulated transmit source is chosen such that a ratio of transmit signal power to at least one optically modulated chaff signal power coupled out at a fiber bend anywhere along the link is smaller than a required signal-to-noise ratio specified by at least one of the at least one optically modulated transmit source'"'"'s corresponding receiver to achieve error-free performance at its output.

3. A secured fiber link system, comprising:

a spatially multiplexing optical fiber;

a transmit spatial multiplexer configured to couple each of a plurality of optical signals into a respective one of a plurality of distinct spatial paths of the spatially multiplexing optical fiber, each of the spatial paths being able to carry an optical signal;

at least one optically modulated transmit source coupled to the transmit spatial multiplexer so that an optically modulated signal supplied as an output from the at least one optically modulated transmit source is coupled by the transmit spatial multiplexer into one of the plurality of spatial paths of the spatially multiplexing optical fiber;

at least one optically modulated chaff source coupled to the transmit spatial multiplexer so that each optically modulated chaff signal supplied as an output from the at least one optically modulated chaff source is coupled by the transmit spatial multiplexer into a respective one of the plurality of spatial paths of the spatially multiplexing optical fiber that are other than the spatial path to which the at least one optically modulated transmit source is coupled, wherein at least one of the at least one optically modulated chaff source occupies substantially a same optical frequency range as at least one of the at least one optically modulated transmit source; and

a receive spatial multiplexer configured to extract at least one spatial path from the spatially multiplexing fiber;

wherein an aggregate optical power of all the optically modulated chaff sources within the optical frequency range substantially occupied by the optically modulated transmit source is chosen such that the aggregate chaff optical signal power coupled out at a fiber bend made at any location along the fiber is larger than an optical power from at least one of the at least one optically modulated transmit source coupled out at the fiber bend.

4. A secured fiber link system, comprising:

a spatially multiplexing optical fiber;

a transmit spatial multiplexer configured to couple each of a plurality of optical signals into a respective one of a plurality of distinct spatial paths of the spatially multiplexing optical fiber, each of the spatial paths being able to carry an optical signal;

at least one optically modulated transmit source coupled to the transmit spatial multiplexer so that an optically modulated signal supplied as an output from the at least one optically modulated transmit source is coupled by the transmit spatial multiplexer into one of the plurality of spatial paths of the spatially multiplexing optical fiber;

at least one optically modulated chaff source coupled to the transmit spatial multiplexer so that each optically modulated chaff signal supplied as an output from the at least one optically modulated chaff source is coupled by the transmit spatial multiplexer into a respective one of the plurality of spatial paths of the spatially multiplexing optical fiber that are other than the spatial path to which the at least one optically modulated transmit source is coupled, wherein at least one of the at least one optically modulated chaff source occupies substantially a same optical frequency range as at least one of the at least one optically modulated transmit source; and

a receive spatial multiplexer configured to extract at least one spatial path from the spatially multiplexing fiber;

wherein an optical power of at least one of the at least one optically modulated chaff source within the optical frequency range substantially occupied by the optically modulated transmit source is chosen such that the chaff optical signal power coupled out at a fiber bend made at any location along the fiber is larger than an optical power from at least one of the at least one optically modulated transmit source coupled out at the fiber bend.

5. A method for securing a fiber link, comprising:

coupling a plurality of optical signals into respective ones of a plurality of spatial paths of a spatially multiplexing optical fiber, wherein at least one of the plurality of optical signals is generated by an optically modulated transmit source to contain real data and wherein at least one of the plurality of optical signals is generated by at least one optically modulated chaff source as an optically modulated chaff signal;

wherein at least the optically modulated chaff signal occupies substantially a same optical frequency range as at least the optical signal that is generated by the optically modulated transmit source;

wherein an aggregate optical power of all the optically modulated chaff sources within the optical frequency range substantially occupied by the optically modulated transmit source is chosen such that a ratio of transmit signal power to optically modulated chaff signal power coupled out at a fiber bend made at any location along the fiber is smaller than a required signal-to-noise ratio specified by the optically modulated transmit source'"'"'s corresponding receiver to achieve error-free performance at its output.

6. A method for securing a fiber link, comprising:

coupling a plurality of optical signals into respective ones of a plurality of spatial paths of a spatially multiplexing optical fiber, wherein at least one of the plurality of optical signals is generated by an optically modulated transmit source to contain real data and wherein at least one of the plurality of optical signals is generated by at least one optically modulated chaff source as an optically modulated chaff signal;

wherein at least the optically modulated chaff signal occupies substantially a same optical frequency range as at least the optical signal that is generated by the optically modulated transmit source;

wherein an optical power of at least one of the at least one optically modulated chaff source within the optical frequency range substantially occupied by the optically modulated transmit source is chosen such that a ratio of transmit signal power to optically modulated chaff signal power coupled out at a fiber bend anywhere along the fiber is smaller than a required signal-to-noise ratio specified by the optically modulated transmit source'"'"'s corresponding receiver to achieve error-free performance at its output.

7. A method for securing a fiber link, comprising:

coupling a plurality of optical signals into respective ones of a plurality of spatial paths of a spatially multiplexing optical fiber, wherein at least one of the plurality of optical signals is generated by an optically modulated transmit source to contain real data and wherein at least one of the plurality of optical signals is generated by at least one optically modulated chaff source as an optically modulated chaff signal;

wherein at least the optically modulated chaff signal occupies substantially a same optical frequency range as at least the optical signal that is generated by the optically modulated transmit source;

wherein an aggregate optical power of all the optically modulated chaff sources within the optical frequency range substantially occupied by the optically modulated transmit source is chosen such that the aggregate chaff optical signal power coupled out at a fiber bend at any point along the fiber is larger than an optical power from the optically modulated transmit source coupled out at the fiber bend.

8. A method for securing a fiber link, comprising:

coupling a plurality of optical signals into respective ones of a plurality of spatial paths of a spatially multiplexing optical fiber, wherein at least one of the plurality of optical signals is generated by an optically modulated transmit source to contain real data and wherein at least one of the plurality of optical signals is generated by at least one optically modulated chaff source as an optically modulated chaff signal;

wherein at least the optically modulated chaff signal occupies substantially a same optical frequency range as at least the optical signal that is generated by the optically modulated transmit source;

wherein an optical power of at least one of the at least one optically modulated chaff source within the optical frequency range substantially occupied by the optically modulated transmit source is chosen such that the chaff optical signal power coupled out at a fiber bend at any point along the link is larger than an optical power from the optically modulated transmit source coupled out at the fiber bend.