Laser based frequency standards and their applications

• US 10,014,653 B2
• Filed: 10/14/2015
• Issued: 07/03/2018
• Est. Priority Date: 10/17/2005
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Hartl, Ingmar, Fermann, Martin
• Primary Examiner(s): BLEVINS, JERRY M
• Application Number:
  US14/883,018
• Publication Number:
  US 20160094010A1
• Time in Patent Office: 993 Days
• Field of Search: 385122
• CPC Class Codes: G02F 1/3528 for producing a supercontinuum
• CPC Class Codes: G02F 1/3558 Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]
• CPC Class Codes: G02F 1/365 in an optical waveguide structure G02F1/377, G02F1/395 take precedence
• CPC Class Codes: G02F 2203/56 Frequency comb synthesizer
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/067 Fibre lasers
• CPC Class Codes: H01S 3/06716 Fibre compositions per se C03C13/04or doping with active elements lasing materials in general H01S3/14
• CPC Class Codes: H01S 3/1112 Passive mode locking

Abstract

Frequency standards based on mode-locked fiber lasers, fiber amplifiers and fiber-based ultra-broad bandwidth light sources, and applications of the same.

Claims

1. A frequency comb based optical source, comprising:

a passively modelocked waveguide oscillator operating at a pulse repetition frequency PRF and providing pulses with a corresponding pulse separation T=1/PRF, said waveguide oscillator comprising a dispersion compensated optical cavity, said optical cavity containing cavity components, wherein said dispersion of said dispersion compensated optical cavity is substantially lower than the dispersion of each of the cavity components; and

an optical distribution system disposed downstream from said passively mode locked waveguide oscillator and operably arranged for optical transmission of a time, frequency, or wavelength standard, said optical distribution system transmitting said time, frequency or wavelength standard to a remote location.

2. The frequency comb based optical source according claim 1, further comprising one or more optical amplifiers.

3. The frequency com based optical source according claim 1, further comprising stabilized fiber links.

4. The frequency comb based optical source according claim 1, wherein said frequency comb based source is arranged as a portion of an optical clock.

5. The frequency comb based optical source according to claim 1, said source configured such that said pulse repetition frequency PRF is characterized by the relationship:

RF=(f_OPT±

f_ceo±

f_beat)/l

where l is an integer representing the mode number of the frequency comb mode closest to f_OPT, f_OPT is the frequency of an optical reference, f_ceo is the carrier envelope offset frequency, and f_beat is the beat frequency between said comb line with said comb mode number 1 and an output of said optical reference,

wherein f_ceo and f_beat are locked to external RF references via phase-locked loops.

6. The frequency comb based optical source according to claim 1, further configured to generate a low noise RF output at an output frequency, said RF output frequency being defined via a fixed relation to said optical reference frequency, f_OPT, said carrier envelope offset frequency f_ceo and said beat frequency f_beat.

7. The frequency comb based optical source according to claim 1, comprising a differential optical delay line constructed such that the pulse separation is decreased by a factor T/N, where N is an integer, with N−

1 representing the number of stages in said differential optical delay line.

8. The frequency comb based optical source according to claim 1, wherein an RF output signal is derived via direct photo-detection with a photodiode, said optical source operably arranged to generate the low noise RF output at an output frequency and to provide low noise operation via limiting excess noise generation in said photodiode and/or providing an output of said modelocked oscillator having a center wavelength at or near a wavelength of maximum sensitivity of said photodiode.