Distribution system for optical reference

• US 9,252,795 B2
• Filed: 10/10/2013
• Issued: 02/02/2016
• Est. Priority Date: 12/15/2010
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Wilkinson, Steven R., Cashen, Matthew T., Clatterbuck, Todd O.
• Primary Examiner(s): Sedighian, M. R.
• Application Number:
  US14/050,468
• Publication Number:
  US 20140035687A1
• Time in Patent Office: 845 Days
• Field of Search: 398/154, 398/155, 398/163, 398/66, 398/68, 398/69, 398/70, 398/71
• US Class Current: 1/1
• CPC Class Codes: G04F 13/02 using optical means
• CPC Class Codes: G04F 5/14 using atomic clocks
• CPC Class Codes: G04G 7/00 Synchronisation radio-controlled time-pieces G04R
• CPC Class Codes: G04G 7/02 by radio
• CPC Class Codes: H01S 3/1303 by using a passive reference, e.g. absorption cell H01S3/139 takes precedence
• CPC Class Codes: H01S 3/1304 by using an active reference, e.g. second laser, klystron or other standard frequency source H01S3/139 takes precedence; automatic control of electronic generators H03L7/00
• CPC Class Codes: H01S 3/1305 Feedback control systems
• CPC Class Codes: H01S 3/2383 Parallel arrangements
• CPC Class Codes: H03L 7/26 using energy levels of molecules, atoms, or subatomic particles as a frequency reference

Abstract

A system for distributing a reference oscillator signal includes a clock having a reference oscillator and a femtosecond laser stabilized by the reference oscillator. The system also includes at least one beamsplitter configured to split the femtosecond laser. The system further includes one or more remote nodes that are spaced from the clock. The remote nodes are configured to generate reference signals based on the split femtosecond laser.

Claims

1. A system for generating distributed timing signals having precision of a reference timing signal comprising:

a reference oscillator arranged to generate the reference timing signal;

a femtosecond laser configured to produce a femtosecond laser pulse sequence stabilized by the reference oscillator, the femtosecond laser pulse sequence having a precision of the reference timing signal to within a portion of a femtosecond;

a transfer laser locked to the femto second laser pulse sequence; and

a plurality of beamsplitters arranged to split an output of the transfer laser into a plurality of split laser pulse sequences for distribution to a plurality of remote nodes that are configured to generate distributed timing signals based on associated ones of the plurality of split laser pulse sequences, the distributed timing signals having the precision of the reference timing signal.

2. The system of claim 1 wherein each pulse of the femtosecond laser pulse sequence has a duration of 10⁻

15 second or less, and

wherein each distributed timing signal is a replica of the reference timing signal having the precision of the reference timing signal.

3. The system of claim 1,

wherein the femtosecond laser is arranged to generate a femtosecond frequency comb which is locked to the reference signal and stabilized by the reference oscillator, and

wherein the plurality of beamsplitters is arranged to distribute the plurality of split laser pulse sequences by distributing the femtosecond frequency comb.

4. The system of claim 1 wherein the reference oscillator and the femto second laser are part of a clock, and

wherein the plurality of remote nodes are spaced apart from the clock.

5. A system for generating distributed timing signals having precision of a reference timing signal comprising:

a reference oscillator arranged to generate the reference timing signal;

a femtosecond laser configured to produce a femtosecond laser pulse sequence stabilized by the reference oscillator, the femtosecond laser pulse sequence having a precision of the reference timing signal to within a portion of a femto second; and

at least one beamsplitter arranged to split the femto second laser pulse sequence into one or more split laser pulse sequences for distribution to one or more remote nodes that are configured to generate distributed timing signals based on associated ones of the one or more split laser pulse sequences, the distributed timing signals having the precision of the reference timing signal;

wherein each remote node is configured to stabilize a phase of an associated one of the split laser pulse sequences based on a reflected version of the split laser pulse sequence that is reflected from the remote node.

6. A system for distributing precision of a reference timing signal comprising:

a reference oscillator arranged to generate the reference timing signal having a precision to within a portion of a femtosecond; and

a femtosecond laser configured to produce a femtosecond frequency comb stabilized by the reference oscillator; and

a plurality of beamsplitters arranged to distribute the femtosecond frequency comb to a plurality of remote nodes that are configured to generate distributed timing signals having the precision of the reference timing signal based on the femtosecond frequency comb.

7. The system of claim 6 further comprising a transfer laser to generate a frequency reference that is locked to the femtosecond frequency comb for distribution to the plurality of remote nodes for generation of the distributed timing signals, and

wherein each remote node is arranged to generate a distributed timing signal by locking the femtosecond frequency comb to the frequency reference of the transfer laser.

8. The system of claim 6 wherein the femtosecond laser is configured to generate a femtosecond laser pulse sequence, and

wherein the femtosecond frequency comb is a frequency comb of the femto second laser pulse sequence.

9. The system of claim 8, wherein the plurality of beamsplitters is arranged to split the femto second laser pulse sequence for distribution to the plurality of remote nodes for generation of the distributed timing signals.

10. A system for distributing precision of a reference timing signal comprising:

a clock comprising a reference oscillator arranged to generate the reference timing signal and a femtosecond laser configured to produce a femtosecond laser pulse sequence stabilized by the reference oscillator and having a femtosecond frequency comb, the reference timing signal having a precision to within a portion of a femtosecond;

a transfer laser locked to the femtosecond laser pulse sequence; and

a plurality of beamsplitters configured to split the an output of the transfer laser for distribution to a plurality of remote nodes,

wherein the plurality of remote nodes are spaced from the clock and configured to generate distributed timing signals having the precision of the reference timing signal.

11. The system of claim 10 wherein the femtosecond frequency comb is distributed to the plurality of remote nodes for use in generation of the distributed timing signals.

12. A system for distributing precision of a reference timing signal comprising:

a clock comprising a reference oscillator arranged to generate the reference timing signal and a femtosecond laser configured to produce a femtosecond laser pulse sequence stabilized by the reference oscillator and having a femtosecond frequency comb, the reference timing signal having a precision to within a portion of a femtosecond; and

at least one beamsplitter configured to split the femtosecond laser pulse sequence for distribution to a plurality of remote nodes, wherein the one or more remote nodes are spaced from the clock and configured to generate distributed timing signals having the precision of the reference timing signal, based on associated ones of the one or more split laser pulse sequences, wherein the femtosecond frequency comb is distributed to the plurality of remote nodes for use in generation of the distributed timing signals; and

a noise reducer for each remote node configured to stabilize a phase of an associated one of the split laser pulse sequences based on a reflected version of the split laser pulse sequence that is reflected from the remote node.

13. A method for distributing precision of a reference timing signal comprising:

generating a reference timing signal with a reference oscillator having a precision to within a portion of femtosecond; and

producing a femtosecond frequency comb stabilized by the reference oscillator; and

distributing the femtosecond frequency comb via a plurality of beamsplitters to a plurality of remote nodes that are configured to generate distributed timing signals having the precision of the reference timing signal based on the femtosecond frequency comb.

14. A method for distributing precision of a reference timing signal, the method comprising:

generating a reference timing signal with a reference oscillator having a precision to within a portion of femtosecond;

producing a femtosecond frequency comb stabilized by the reference oscillator;

distributing the femtosecond frequency comb to a plurality of remote nodes that are configured to generate distributed timing signals having the precision of the reference timing signal based on the femtosecond frequency comb; and

generating a frequency reference that is locked to the femtosecond frequency comb for distribution to the plurality of remote nodes for generation of the distributed timing signals,

wherein each remote node is arranged to generate a distributed timing signal by locking the femtosecond frequency comb to a frequency reference of a transfer laser.

15. An airborne platform comprising:

a reference node comprising a reference oscillator for generating a reference timing signal having a precision to within a portion of femtosecond;

a plurality of remote sensor nodes located on the airborne platform and spaced apart from the reference node,

wherein the reference node is arranged to produce a femtosecond frequency comb stabilized by the reference oscillator and to distribute the femtosecond frequency comb to a plurality of remote sensor nodes,

wherein the remote sensor nodes are configured to generate distributed timing signals having the precision of the reference timing signal based on the femtosecond frequency comb.