Surface emitting laser, surface-emitting-laser array, and image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorMitsuhiro Ikuta
Life of this patent
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Abstract
The present invention provides a surface emitting laser that provides a sufficient optical output and is suitable as a light source intended for electrophotographic apparatuses, and a surface-emitting-laser array and an image forming apparatus each including the surface emitting laser. The surface emitting laser includes a first stepped structure on a front surface of a front mirror. In the first stepped structure, a difference L between an optical path length in a first area and an optical path length in a second area satisfies the following expression: (¼+N)λ<|L|<(¾+N)λ where N is an integer.
Claims19
A surface emitting laser configured to oscillate at a wavelength λ, comprising:
- a substrate;
- a multilayer structure provided on the substrate and in which layers including a rear mirror, an active layer, and a front mirror are stacked;
- and
- a first stepped structure provided on a front surface of the front mirror and including a portion extending in a first area defined in a central part of an emission area and a portion extending in a second area defined on the outer side of the first area within the emission area, the portions having different heights,
- wherein, in terms of an optical path length from a plane defined on the outside of the surface emitting laser and extending perpendicular to a stacking direction of the multilayer structure to the front surface of the front mirror, a difference L between the optical path length in the first area and the optical path length in the second area satisfies the following expression:
- (¼+N)λ<|L|<(¾+N)λ
- where N is an integer, and
- wherein the first stepped structure has an optical thickness that is an integral multiple of λ/2 in each of the first area and the second area.
Dependencies are inferred from the claim text.