US 10,707,648 B2 · Stable linewidth narrowing of a coherent comb laser

Abstract

A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

Claims20

Dependent claims

A method for narrowing a linewidth of a coherent comb laser (CCL) comprising:

providing a mode-locked semiconductor coherent comb laser (CCL) with a laser cavity defined by an active gain material in a waveguide between two facets, the CCL adapted to output of at least 4 mode-locked lines, each with an original linewidth of less than 100 MHz;
tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam;
propagating the tapped beam using an optical circulator to an attenuator to produce an attenuated beam and propagating the attenuated beam back to the laser cavity, on a solid waveguide;
and
reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam,
where the reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth, and
an optical path between tapping and reinsertion is polarization maintaining.

4 more elements

A narrow linewidth multi-wavelength laser (MWL) comprising:

a mode-locked semiconductor coherent comb laser (CCL) with a primary laser cavity defined by an active gain material in a waveguide between two facets, the CCL adapted to output of at least 4 mode-locked lines, each with an original linewidth of less than 100 MHz;
and
a secondary laser cavity including a optical circulator coupled to the primary laser cavity for tapping a beam of the CCL and propagating the tapped beam to an attenuator and reinserting the attenuated beam into the primary laser cavity at a power less than 10% of a power of the tapped beam, the secondary laser cavity consisting of polarization maintaining solid waveguides between polarization maintaining components,
wherein a linewidth of each of the at least 4 lines is reduced in proportion to a difference in optical path length between the secondary laser cavity and the primary laser cavity.

1 more element

Dependencies are inferred from the claim text.

Stable linewidth narrowing of a coherent comb laser

Life of this patent

Stable linewidth narrowing of a coherent comb laser

Life of this patent

Abstract

Claims20