Tapered Stripe Semiconductor Laser for COD and SHB Reduction

The patent applies local quality by creating a tapered stripe structure where the waveguide width varies along the resonator length. The front end face has a wider width to reduce light density and prevent COD, while the rear end face maintains a narrower width for effective light extraction. This non-uniform width distribution optimizes different regions for different functions: the front region for damage prevention and the rear region for light output efficiency.

The patent employs asymmetry by designing a tapered stripe structure with different widths at the front and rear end faces. The asymmetric width distribution creates a gradual transition in the optical field and carrier concentration profile, which reduces SHB effects while maintaining the protective function against COD. The asymmetric structure allows for more uniform carrier distribution compared to a symmetric end-face window design.

The patent applies dynamics by implementing a tapered stripe structure where the waveguide width changes gradually along the resonator length. This dynamic width variation allows the optical mode to adapt continuously from the narrow rear end to the wider front end, optimizing both light extraction at the rear and light density reduction at the front. The gradual transition prevents abrupt changes in light distribution that would otherwise cause energy loss.

The patent applies parameter changes by systematically varying the waveguide width parameter along the resonator length to create a tapered profile. This parameter variation optimizes the balance between reducing SHB and maintaining manufacturability. The specific taper ratio and width values are carefully selected to achieve low operating current while using standard fabrication processes that can handle the tapered geometry.