Surface emitting laser and image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorMitsuhiro Ikuta
Life of this patent
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Abstract
A first stepped structure configured to apply a reflectance difference and a second stepped structure configured to change a far field light intensity distribution are provided. A region in which a level difference of the first stepped structure is formed has a predetermined relationship with a region in which a level difference of the second stepped structure is formed.
Claims19
A surface emitting laser including a laminated structure including a substrate, and a lower mirror, an active layer, and an upper mirror formed on the substrate configured to oscillate at a wavelength λ, the surface emitting laser comprising:
- a first stepped structure provided in a light outgoing region on an upper part of the upper mirror and including a level difference formed between a first region arranged in a center portion of the light outgoing region and a second region provided outside the first region;
- and
- a second stepped structure provided in the light outgoing region on the upper part of the upper mirror and including a level difference formed between a third region provided outside the first region and a fourth region provided outside the third region,
- wherein the level difference of the second stepped structure exists in the second region;
- reflectance of a structure including the upper mirror, the first stepped structure, and the second stepped structure in the first region is higher than that in the second region with respect to light perpendicularly made incident to the substrate and having a wavelength λ;
- and
- a phase difference between transmitted light of the third region and transmitted light of the fourth region is greater than a phase difference between transmitted light of the first region and transmitted light of the third region.
A surface emitting laser including a laminated structure including a substrate, and a lower mirror, an active layer, and an upper mirror formed on the substrate configured to oscillate at a wavelength λ, the surface emitting laser comprising:
- a first stepped structure provided in a light outgoing region on an upper part of the upper mirror and including a level difference formed between a first region arranged in a center portion of the light outgoing region and a second region provided outside the first region;
- and
- a second stepped structure provided in the light outgoing region on the upper part of the upper mirror and including a level difference formed between a third region provided outside the first region and a fourth region provided outside the third region,
- wherein the level difference of the second stepped structure exists in the second region;
- reflectance of a structure including the upper mirror, the first stepped structure, and the second stepped structure in the first region is higher than that in the second region with respect to light perpendicularly made incident to the substrate and having a wavelength λ;
- and
- a phase difference between transmitted light of the third region and transmitted light of the fourth region is closer to π than a phase difference between transmitted light of the first region and transmitted light of the third region.
Dependencies are inferred from the claim text.