Laser array with wide-waveguide coupling region

Claim 2

A semiconductor laser array structure, comprising: means for producing lasing action in the structure, including a substrate, an active semiconductor layer, electrodes for applying a voltage across the active layer, and a pair of reflective facets, at least one of which is an emitting facet, located at opposite ends of the array structure; a first set of waveguides with parallel longitudinal axes; a second set of waveguides with parallel longitudinal axes; a wide-waveguide section, having first and second ends coupled to the first and second sets of waveguides, respectively, having a length sufficient to support a single lateral mode in the wide-waveguide section, and having a width at the first end approximately equal to the overall width of the first set of waveguides and a width at the second end approximately equal to the overall width of the second set of waveguides; and wherein the individual waveguides in one set are not colinear with the waveguides in the other set.

Claim 3

A semiconductor laser array structure as defined in claim 1, wherein: the two sets of waveguides in each set have substantially equal individual widths and have substantially equal periodic waveguide spacings measured at any transverse line through the waveguides of a set.

Claim 4

A semiconductor laser array structure as defined in claim 2, wherein: the individual waveguide width is larger than approximately fifty percent of the periodic waveguide spacing at the emitting facet, to ensure a far-field radiation pattern that is substantially single-lobed.

Claim 5

A semiconductor laser array structure as defined in claim 3, wherein: the first and second sets of waveguides each include a tapered region in which the individual waveguide width is progressively increased until the individual waveguides meet the wide-waveguide section.

Claim 6

A semiconductor laser array structure as defined in claim 4, wherein: there is one more waveguide in the second set of waveguides than in the first set of waveguides; and the individual waveguides in the second set are aligned with the midpoints between waveguides of the first set.

Claim 7

A semiconductor laser array structure as defined in claim 5, wherein: the individual waveguides are defined in part by inter-waveguide regions that are of constant width except in the tapered regions, where the inter-waveguide regions taper to a negligible width.

Claim 8

A semiconductor laser array structure, comprising: means for producing lasing action in the structure, including a substrate, an active semiconductor layer, electrodes for applying a voltage across the active layer, and a pair of reflective facets, at least one of which is an emitting facet, located at opposite ends of the array structure; a first set of waveguides with parallel longitudinal axes; a second set of waveguides with parallel longitudinal axes; a wide-waveguide section, having first and second ends coupled to the first and second sets of waveguides, respectively; having a length sufficient to support a single lateral mode in the wide-waveguide section, and having a width at the first end approximately equal to the overall width of the first set of waveguides and a width at the second end approximately equal to the overall width of the second set of waveguides; and wherein each of the two sets of waveguides have substantially equal individual widths and substantially equal periodic spacings measured at any transverse line through the waveguides of a set, but the individual waveguide widths vary along portions of the parallel longitudinal axes, to effect transitions to and from the wide-waveguide section, and wherein the individual waveguide widths at the emitting facet are at least fifty percent of the periodic waveguide spacing, to ensure a far-field radiation pattern that is substantially single-lobed and diffraction-limited, and the individual waveguides in one set are not collinear with waveguides in the other set, to inhibit coupling of a 180-degree-phase-shift array mode from one set of waveguides to the other.

Claim 9

A semiconductor laser array structure, comprising: means for producing lasing action in the structure, including a substrate, an active semiconductor layer, electrodes for applying a voltage across the active layer, and a pair of reflective facets, at least one of which is an emitting facet, located at opposite ends of the array structure; a first set of waveguides with parallel longitudinal axes; a second set of waveguides with parallel longitudinal axes; a wide-waveguide section, having first and second ends coupled to the first and second sets of waveguides, respectively; having a length sufficient to support a single lateral mode in the wide-waveguide section, and having a width at the first end approximately equal to the overall width of the first set of waveguides and a width at the second end approximately equal to the overall width of the second set of waveguides; and wherein each of the two sets of waveguides have substantially equal individual widths and substantially equal periodic spacings measured at any transverse line through the waveguides of a set, but the individual waveguide widths vary along portions of the parallel longitudinal axes, to effect transitions to and from the wide-waveguide section, and wherein the individual waveguide widths at the emitting facet are at least fifty percent of the periodic waveguide spacing, to ensure a far-field radiation pattern that is substantially single-lobed and diffraction-limited, and the individual waveguides in one set are not collinear with waveguides in the other set, to inhibit coupling of a 180-degree-phase-shift array mode from one set of waveguides to the other.

Claim 10

A semiconductor laser array structure as defined in claim 7, wherein: the first and second sets of waveguides each include a tapered region in which the individual waveguide width is progressively increased until the individual waveguides meet the wide-waveguide section.

Claim 11

A semiconductor laser array structure as defined in claim 8, wherein: there is one more waveguide in the second set of waveguides than in the first set; and the individual waveguides in the second set are aligned with the midpoints between waveguides of the first set.

Claim 12

A semiconductor laser array structure as defined in claim 9, wherein: the individual waveguides are defined in part by inter-waveguide regions that are of constant width except in the tapered regions, where the interwaveguide regions taper to a negligible width.