Optical frequency comb generator with carrier envelope offset frequency detection
AssigneeIpg Photonics Corporation
InventorSergey VASILYEV
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Abstract
The present invention provides systems and methods for optical frequency comb generation with self-generated optical harmonics in mode-locked lasers for detecting the carrier envelope offset frequency. The mode-locked laser outputs an optical frequency comb and a harmonic output. The harmonic output provides an optical heterodyne resulting in a detectable beat note. A carrier envelope offset frequency detector detects the beat note and generates an optical frequency comb signal. The signal can be used to stabilize the optical frequency comb output.
Claims15
An optical frequency comb generator system comprising,
- a mode-locked laser that oscillates within a fundamental optical frequency comb spectrum and simultaneously generates an optical frequency comb output and a heterodyne output, the heterodyne output comprising a first spectral component from a first auxiliary optical frequency comb and a second spectral component from a second auxiliary optical frequency comb, at least one of the first and second auxiliary optical frequency combs comprising an optical harmonic of the fundamental optical frequency comb, the optical frequency comb output characterized by a carrier envelope offset frequency, wherein the mode-locked laser comprises a laser pump source and a femtosecond (fs) oscillator;
- and
- a carrier envelope offset frequency detector configured to receive and detect the first and second spectral components, wherein the carrier envelope offset frequency detector is further configured to generate a signal corresponding to the carrier envelope offset frequency.
The system as in one of the above claims, the fs oscillator being configured with a nonlinear laser medium, wherein the mode-locked laser generates the optical frequency comb output and self-generates at least one optical harmonic in the nonlinear laser medium.
The system as in one of the above claims, wherein the mode-locked laser operates such that the laser output further comprises an optical heterodyne with a beat note frequency that corresponds to the carrier envelope offset frequency, wherein the carrier envelope offset frequency detector detects the carrier envelope offset frequency.
The system as in one of the above claims, wherein the first and second auxiliary optical frequency combs partially spectrally overlap.
The system as in one of the above claims, wherein the first and second auxiliary optical frequency combs comprise the fundamental and any other harmonic optical frequency combs.
The system as in one of the above claims, wherein the first and second auxiliary optical frequency combs comprise any two distinct harmonic optical frequency combs.
The system as in one of the above claims, further comprising at least one spectral broadening element operative to broaden at least one of the first and second auxiliary optical frequency combs such that the first and second auxiliary optical frequency combs overlap, wherein the spectral broadening element is located between the fs oscillator and the carrier envelope offset frequency detector.
The system as in one of the above claims, the mode-locked laser further comprising a resonator cavity tailored for increased output at one or more optical harmonics.
The system as in one of the above claims, further comprising at least one spectra filter configured to modify the spectral content of the heterodyne output.
The system as in one of the above claims, wherein the carrier envelope offset frequency detector is configured to provide a signal used to control the carrier envelope offset frequency and thereby stabilize the optical frequency comb output.
In a mode-locked laser based system with an optical frequency comb output and a heterodyne output, the optical frequency comb output characterized by a carrier envelope offset frequency, a method of providing an optical frequency comb comprising;
- simultaneously generating an optical frequency comb output and a heterodyne output with a mode-locked laser;
- detecting a beat note between spectral components of respective first and second auxiliary optical frequency combs in the heterodyne output;
- and
- generating a signal corresponding to the carrier envelope offset frequency based on the detected beat note.
A method of detecting a carrier envelope offset frequency in a Kerr lens mode-locked mid-IR polycrystalline Cr:ZnS oscillator based laser system with a self-generating harmonic output, the method comprising;
- simultaneously generating an optical frequency comb output and one or more optical harmonics directly in the Cr:ZnS material;
- detecting a heterodyne beat note between a first spectral component and a second spectral component of respective first and second auxiliary optical frequency combs that comprise at least one of the one or more optical harmonics, and
- generating a signal corresponding to the carrier envelope offset frequency based on the detected beat note.
Dependencies are inferred from the claim text.