US 12,724,320 B1 · Widely tunable frequency doubled light source

Abstract

A widely tunable frequency doubled light source includes a fundamental widely tunable laser emitting fundamental radiation tuned over a fundamental wavelength range and a broadband nonlinear waveguide which frequency doubles the fundamental radiation over a frequency doubled wavelength range. A preferred implementation of the widely tunable laser is a MEMS-VCSEL followed by a semiconductor optical amplifier. Preferred implementations of the nonlinear waveguide include periodically poled lithium niobate with various means for broadening a conversion bandwidth, including dispersion engineering to reduce a group velocity mismatch between fundamental and frequency doubled wavelengths and employing a chirped poling period. Various optical systems are enabled by this new frequency doubled light source, including swept source optical coherence tomography (SSOCT) at previously inaccessible wavelength ranges, such as in the green/yellow gap range from about 500 nm to about 600 nm. Other optical systems enabled by the widely tunable frequency doubled light source include systems for optical spectroscopy, beam steering, Raman spectroscopy, and wavelength division multiplexed optical communications.

Claims19

Dependent claims

A tunable light source operative to emit tunable frequency doubled radiation over a frequency doubled wavelength range, having a frequency doubled center wavelength, said tunable light source comprising:

a widely tunable semiconductor laser operative to emit fundamental radiation over a fundamental wavelength range having a fundamental center wavelength that is twice said frequency doubled center wavelength, wherein said fundamental wavelength range exceeds 1% of said fundamental center wavelength, and
an etched nonlinear waveguide comprising a nonlinear material waveguide core designed to simultaneously frequency double all wavelengths over at least said fundamental wavelength range, wherein said tunable frequency doubled radiation emerges from an output side of said etched nonlinear waveguide, said fundamental radiation enters an input side of said etched nonlinear waveguide,
wherein said etched nonlinear waveguide has a group velocity mismatch (GVM) between said fundamental center wavelength and said frequency doubled center wavelength that passes below 300 femtoseconds/mm as a function of a width of said etched nonlinear waveguide, and
wherein the frequency doubled wavelength range of the tunable frequency doubled radiation that is emitted by the etched nonlinear waveguide includes frequency-doubled wavelengths between 520 nm and 610 nm.

1 more element

Dependencies are inferred from the claim text.

Widely tunable frequency doubled light source

Life of this patent

Widely tunable frequency doubled light source

Life of this patent

Abstract

Claims19