Low temperature distributed feedback laser with loss grating and method
AssigneeAgere Systems Guardian Corp.
InventorsLars E. Eng, Ram Jambunathan, Kishore K. Kamath, Alexander Robertson, Daniel Paul Wilt
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Abstract
A low threshold distributed feedback (DFB) laser is constructed for improved performance at subzero temperatures. A loss grating is employed to enhance the probability that lasing occurs near the short wavelength side of the stopband and to counteract the effect of negative gain tilt that occurs when DFB lasers are positively detuned. A method of making DFB lasers from wafers with improved yield for low temperature side mode suppression ratio (SMSR) is also disclosed.
Claims6
A distributed feedback laser for low temperature operation, said laser comprising:
- an active layer for producing optical gain in response to an electrical current;
- a loss grating for shifting the emission spectrum of said laser to the short wavelength side of a stopband;
- a spacer layer located between said active layer and said loss grating;
- and
- cleaved facets on opposed ends, and wherein said facets intersect said loss grating such that respective phase relationships are defined between said cLeaved facets and said loss grating, and wherein the respective phase relationships bctween said cleaved facets and said loss grating are such that said laser has a lasing symmetry Lsym that is greater than 0.5.
Dependencies are inferred from the claim text.