Microoptic lenses
AssigneeUniversity of California
InventorJames J. Snyder
Life of this patent
Estimating the term…
Abstract
The present invention provides several novel diffraction limited microlens configurations which are especially valuable for use in conjunction with laser diodes, and optical fibers. Collimators, circularizers and focusers (couplers) are provided.
Claims35
A crossed microlens system for collimating the output of a diode laser, comprising:
- a diode laser outputting a laser beam from a noncircular aperture having a fast axis defined by the narrowest dimension of said noncircular aperture, and a slow axis orthogonal to said fast axis, said fast axis diverging faster than the slow axis;
- first cylindrical microlens means having a shape and position for collimating said diode laser beam in a plane parallel to the fast axis;
- and
- second cylindrical microlens means having a shape and position for collimating light from said first lens means in a plane parallel to the slow axis.
A microlens system for circularizing an output beam from a diode laser having a fast axis and a slow axis, said microlens system comprising:
- a diode laser outputting a laser beam from a noncircular aperture having a fast axis defined by the narrowest dimension of said noncircular aperture, and a slow axis orthogonal to said fast axis, said fast axis diverging faster than the slow axis;
- first microlens surface means positioned in the laser beam for reducing divergence of the laser beam along the fast axis;
- and
- second microlens surface means spaced apart by a spaced apart distance from said first microlens surface means, said second microlens surface positioned in the laser beam for changing the divergence of the laser beam so that it is equivalent to the divergence of the output beam along the slow axis, said spaced apart distance chosen to circularize the output beam.
A microlens for controlling the aspect ratio and divergence of a light beam having a first axis and an orthogonal axis, the divergence of the light beam being defined to include positive and negative divergences, the light beam having an aspect ratio defined by the ratio of a first beam diameter on the first axis to a second beam diameter on the orthogonal axis, said microlens comprising:
- a first noncircular curved surface for changing the divergence of the light beam along the first axis from a first divergence to an intermediate divergence;
- and
- a second curved surface for changing the divergence of the beam along the first axis from the intermediate divergence to a second divergence, said second curved surface spaced apart from said first curved surface a first distance selected to provide a first aspect ratio at the second curved surface.
A method for changing the aspect ratio and divergence of a source light beam first to an intermediate beam and then to an output beam, said beams having a cross-section defined by a first axis and an orthogonal axis and an aspect ratio defined by the ratio of a first beam diameter on the first axis to a second beam diameter on the orthogonal axis that may vary with the distance of propagation, the divergence being defined to include positive and negative divergences, said method comprising the steps of:
- (a) supplying a source light beam having a first divergence along the first axis and a second divergence along the orthogonal axis;
- (b) converting the first divergence along the first axis of the source beam to an intermediate divergence along the first axis of an intermediate beam by applying the source light beam to a first microlens surface that defines a first curved shape where the first axis meets said first microlens surface, said first curved shape differing in curvature from a second shape defined where the second axis of the source beam meets said first microlens surface;
- (c) converting the intermediate divergence along the first axis of the intermediate beam to a first output divergence along the first axis by applying the intermediate light beam to a second microlens surface defining a third curved shape where the first axis of the intermediate light beam meets said first microlens surface, said third curved shape differing in curvature from a fourth shape defined where the second axis meets said second microlens surface, said second microlens surface spaced apart from the first microlens surface by a first distance selected to provide a first aspect ratio of the intermediate light beam, to provide an output beam having a selected aspect ratio and divergence.
An optical source and microlens assembly for providing an output beam having a selected aspect and divergence, the divergence being defined to include positive and negative divergences, said assembly comprising:
- an optical source having a noncircular output aperture that defines a fast axis by the narrowest dimension of said noncircular aperture and a slow axis orthogonal to the fast axis, said optical source emitting a source beam wherein the fast axis defines a first divergence and a slow axis defines a second divergence, said source beam having an aspect ratio which varies with propagation distance, the aspect ratio defined by the ratio of a source beam first diameter on the fast axis to a source beam second diameter on the slow axis;
- and
- a microlens, including
- first surface means for changing the divergence of the beam along the fast axis from a first divergence to an intermediate divergence, said first surface means comprising a noncircular shape on the fast axis;
- and
- second surface means for changing the divergence of the beam along the fast axis from the intermediate divergence to an output divergence of an output beam, said second surface means spaced apart from said first surface means a first distance selected to provide a selected aspect ratio at the second surface.
A crossed microlens system for changing the aspect and divergence of a light beam having a cross-section defined by a first axis and an orthogonal axis, the divergence being defined to include positive and negative divergences, said microlens system comprising:
- a first cylindrical microlens positioned in the light beam so that the divergence of the light beam on the first axis is changed;
- and
- a second cylindrical microlens spaced a first distance from the first cylindrical lens, said second cylindrical microlens crossed orthogonally with the first cylindrical microlens, so that the second cylindrical lens changes the divergence of the light beam on the orthogonal axis.
A crossed microlens system for focusing a light beam having a cross-section defined by a first axis and an orthogonal axis, said microlens system comprising:
- a first cylindrical microlens and a second cylindrical microlens positioned with its cylindrical axis crossed orthogonally with the first cylindrical microlens, said first cylindrical microlens having a shape for focusing light energy along the first axis of the light beam at a first focal point, and said second cylindrical microlens having a shape for focusing light energy along the orthogonal axis of the light beam at a second focal point.
A crossed microlens system for coupling a first optical fiber with an approximately collimated light beam having a cross-section defined by a first axis and an orthogonal axis, said microlens system comprising:
- a first cylindrical microlens and a second cylindrical microlens positioned with its cylindrical axis crossed orthogonally with the first cylindrical microlens, said first cylindrical microlens having a shape for focusing light energy along the first axis of the light beam at a first focal point, and said second cylindrical microlens having a shape for focusing light energy along the orthogonal axis of the light beam at a second focal point;
- wherein the first and the second focal points are positioned with respect to the optical fiber so that the light beam is substantially coupled with the fiber.
Dependencies are inferred from the claim text.