Linear polarization of semiconductor laser
First Claim
1. A vertical cavity surface emitting laser emitting optical radiation at a wavelength, λ
- , comprising;
first and second parallel mirrors forming therebetween an optical cavity; and
an active region disposed between the mirrors, the active region comprising at least one strained semiconductor layer, the strained semiconductor layer having a preferred direction of electrical conductivity substantially along a first direction parallel to the mirrors, and said laser emitting optical radiation having a polarization substantially parallel to this first direction.
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Abstract
This invention discloses vertical cavity surface emitting lasers (VCSELs) formed to emit optical radiation that has a controlled direction of polarization. In one embodiment, a VCSEL has an active region that contains at least one strained semiconductor layer which has a preferred direction of electrical conductivity due to the strain. As a result, the optical radiation emitted from the VCSEL has a direction of polarization that is parallel to the preferred direction of conductivity. In another embodiment, a VCSEL has an elongated active region, and the direction of polarization of the radiation emitted from the VCSEL is parallel to a longitudinal axis of the active region. The invention also discloses a VCSEL array comprising vertical cavity surface emitting lasers having elongated active regions. By forming the elongated active regions parallel to each other, the array emits optical radiation having parallel polarization. Alternatively, the array may be formed so that the elongated active regions of adjacent VCSELs of the array are perpendicular to each other. As a result, adjacent VCSELs in the array emit optical radiation having orthogonal polarizations.
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Citations
19 Claims
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1. A vertical cavity surface emitting laser emitting optical radiation at a wavelength, λ
- , comprising;
first and second parallel mirrors forming therebetween an optical cavity; and an active region disposed between the mirrors, the active region comprising at least one strained semiconductor layer, the strained semiconductor layer having a preferred direction of electrical conductivity substantially along a first direction parallel to the mirrors, and said laser emitting optical radiation having a polarization substantially parallel to this first direction. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- , comprising;
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8. A vertical cavity surface emitting laser emitting optical radiation having a wavelength, λ
- , comprising;
first and second parallel mirrors forming therebetween an optical cavity; and an elongated active region disposed between the mirrors, the elongated active region having longitudinal and transverse axes oriented in directions substantially perpendicular to the direction of emitted optical radiation, the dimension of the active region along the transverse axis being sufficiently small that the laser emits optical radiation having substantially a fundamental mode along the transverse axis and the optical radiation having a direction of polarization substantially parallel to the longitudinal axis. - View Dependent Claims (9, 10, 11, 12, 13, 14)
- , comprising;
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15. A vertical cavity surface emitting laser array comprising:
a plurality of vertical cavity surface emitting lasers integrally formed on a substrate, each of the lasers having an elongated active region, each elongated active region having longitudinal and transverse axes oriented in directions substantially perpendicular to the direction in which the laser emits optical radiation, the dimension of each active region along the transverse axis being sufficiently small that each laser emits optical radiation having substantially a fundamental mode along the transverse axis, and the optical radiation from each laser having a direction of polarization substantially parallel to the longitudinal axis of the active region of the laser. - View Dependent Claims (16, 17, 18, 19)
Specification