Ultralow noise mode-locked laser and RF sinewave source
First Claim
1. A method of generating precise optical timing signals having a frequency greater than approximately 12.4 GHz from a mode locked laser source comprising the steps of:
- Automatically self-starting an optical loop of a mode locked laser source optoelectronic loop oscillator operating at greater than approximately 12.4 GHz;
Producing a periodic comb of phase-locked longitudinal modes from the mode locked laser source;
Selecting two of said phase-locked longitudinal modes from said optical loop of the mode locked laser source;
Producing a beat note from said selected two phase-locked longitudinal modes;
Delaying the produced beat note in a delay line, having a length of about 100 meters, between an optical circulator of the optical loop and a photodiode of an electrical loop said delay line coupling the electrical loop with the optical loop;
Detecting said delayed beat note pulses at the electrical loop coupled with the optical loop and generating an electrical beat pulse;
Dividing said electrical beat pulses by a selected integer to form an electrical controlling signal;
Controlling an optical modulator coupling said optical loop with said electrical loop with said electrical controlling signal to mode lock said laser source on a selected harmonic of a fundamental frequency of said optical loop; and
Coupling said harmonic of said laser source to an optical output as the optical timing signal to drive a harmonic mode-locked laser.
1 Assignment
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Accused Products
Abstract
Systems, devices and methods of generating both a precision electrical timing signal as well as a precision optical timing signal. A novel, modified opto-electronic loop oscillator is used to drive a harmonic mode-locked laser. A novel opto-electronic loop has a larger “Q” factor by increasing the electrical loop oscillating frequency ω0 by using a beat note created by the selection of two optical longitudinal modes from the mode-locked laser. The beat note is detected and divided down to drive a modulator that mode-locks the laser. The frequency division stage also reduces the noise.
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Citations
9 Claims
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1. A method of generating precise optical timing signals having a frequency greater than approximately 12.4 GHz from a mode locked laser source comprising the steps of:
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Automatically self-starting an optical loop of a mode locked laser source optoelectronic loop oscillator operating at greater than approximately 12.4 GHz; Producing a periodic comb of phase-locked longitudinal modes from the mode locked laser source; Selecting two of said phase-locked longitudinal modes from said optical loop of the mode locked laser source; Producing a beat note from said selected two phase-locked longitudinal modes; Delaying the produced beat note in a delay line, having a length of about 100 meters, between an optical circulator of the optical loop and a photodiode of an electrical loop said delay line coupling the electrical loop with the optical loop; Detecting said delayed beat note pulses at the electrical loop coupled with the optical loop and generating an electrical beat pulse; Dividing said electrical beat pulses by a selected integer to form an electrical controlling signal; Controlling an optical modulator coupling said optical loop with said electrical loop with said electrical controlling signal to mode lock said laser source on a selected harmonic of a fundamental frequency of said optical loop; and Coupling said harmonic of said laser source to an optical output as the optical timing signal to drive a harmonic mode-locked laser. - View Dependent Claims (2, 3)
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4. A method of generating precise microwave timing signals from a self-starting mode-locked laser optoelectronic oscillator comprising the steps of:
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Producing a periodic comb of phase-locked longitudinal modes from the self-starting optical loop of the mode-locked laser optoelectronic oscillator mode locked at greater than approximately 12.4 GHz Selecting two of said phase-locked longitudinal modes from said optical loop; Producing a beat mode from said selected two phase-locked longitudinal modes; Delaying the beat mode in a delay line, having a length of about 100 meters, between an optical circulator of the optical loop and a photodiode of an electrical loop; Detecting said delayed beat mode pulses and generating an electrical beat pulse in the electrical loop of said optoelectronic oscillator; Dividing said electrical beat pulses mode by a selected integer to form an electrical controlling signal; Controlling an optical modulator coupling said optical loop with said electrical loop with the said electrical controlling signal whereby said laser is locked on a selected harmonic of the fundamental frequency of the optical loop; and Coupling said electrical controlling signal to an output as a microwave timing signal. - View Dependent Claims (5, 6, 7)
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8. A method of generating precise optical and electrical timing signals for a mode-locked laser and RF sinewave source comprising the steps of:
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Automatically self-starting an optical loop and an electrical loop of an optoelectronic oscillator from background noise; Generating a beat pulse signal from a laser source in an optical loop of the optoelectronic oscillator, the optical loop operating at greater than approximately 12.4 GHz; Coupling the generated beat pulse signal from an optical circulator of said optical loop to a filter, which filters the beat pulse and couples said beat pulse into a delay line, having a length of about 100 meters, between said filter and a photodiode of the electrical loop of the optoelectronic oscillator; The electrical loop operating at a frequency greater than approximately 12.4 GHz; Converting the filtered and delayed beat pulse signal into an electrical drive timing signal in the electrical loop including dividing the electrical drive timing signal by an integer; and Modulating the laser source with the electrical drive timing signal so that the laser source is mode-locked to a selected harmonic of a fundamental frequency of the laser source.
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9. An optical timing signal generating system for lasers comprising:
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An automatically self-starting optical loop laser source for generating an optical beat pulse signal, the optical loop operating at greater than approximately 12.4 GHz; A modifier for modifying the beat pulse signal into an electrical drive timing signal in an electrical loop coupled with the optical loop, the modifier comprising; An optical filter for filtering the optical beat pulse signal coupled, from an optical circulator of said optical loop, into the electrical loop; An optical delay device, including an optical delay line, having a length of about 100 meters, between said filter and a detector, of the electrical loop, for adding a delay to the filtered optical beat pulse signal; the detector for detecting the filtered and delayed optical beat pulse signal and converting optical beat pulse signal to an electrical drive timing signal; and A modulator for modulating the laser source with the electrical drive timing signal so that the laser source is mode-locked to a selected harmonic of a fundamental frequency of the laser source.
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Specification