This invention relates to the field of optics and more particularly to an optical fiber having first and second reflective surfaces.
Fiber optic communication systems include optical components, such as optical fibers, that transmit and receive optical signals. An optical signal propagating through an input optical fiber may exit the input optical fiber at a particular angle for communication to an output optical fiber. The various optical components of a system, such as the optical fibers, are generally positioned with respect to each other using V-grooves, or other similarly pre-fabricated alignment tools. A problem with prior fiber optic communication systems is that the pre-fabricated alignment tools may not be able to support the output optical fiber in a position appropriate for receiving the optical signal from the input optical fiber. One approach to solve this problem attempts to custom manufacture alignment tools to accommodate optical fibers that receive optical signals at various angles. This approach is costly, time consuming, and inefficient.
An optical fiber having first and second reflective surfaces is provided that substantially eliminates or reduces disadvantages and problems associated with prior optical fibers.
In accordance with one embodiment of the present invention, an optical fiber includes an endface having a first reflective surface and a second reflective surface. The first reflective surface is formed at a first bias angle with respect to a plane that is normal to the longitudinal axis of the optical fiber. The first reflective surface totally internally reflects an optical signal at a first reflection angle with respect to the longitudinal axis. The second reflective surface is coupled to the first reflective surface and formed at a second bias angle with respect to the plane such that the second reflective surface totally internally reflects the optical signal at a selected second reflection angle.
Another embodiment of the present invention is a method of forming an endface of an optical fiber that includes forming a first reflective surface at a first bias angle with respect to a plane that is normal to the longitudinal axis of the optical fiber such that the first reflective surface totally internally reflects an optical signal at a first reflection angle with respect to the longitudinal axis. The method further includes forming a second reflective surface at a second bias angle with respect to the plane such that the second reflective surface totally internally reflects the optical signal at a selected second reflection angle.
Yet another embodiment of the present invention is a method for communicating an optical signal using an optical fiber. The method includes propagating an optical signal along the longitudinal axis of an optical fiber and totally internally reflecting the optical signal at a first reflective surface, wherein the first reflective surface is formed at a first bias angle with respect to a plane that is normal to the longitudinal axis of the optical fiber. The method further includes propagating the optical signal at a first reflection angle with respect to the longitudinal axis in response to totally internally reflecting the optical signal. The method concludes by totally internally reflecting the optical signal at a second reflective surface, wherein the second reflective surface is formed at a second bias angle with respect to the plane such that the optical signal propagates at a selected second reflection angle.
Technical advantages of the present invention include an optical fiber having an endface with a first reflective surface and a second reflective surface. The first reflective surface may be formed at a first bias angle that allows the incident angle of an optical signal to be sufficiently greater than the appropriate critical angle of refraction while still achieving a selected exit angle for the signal. This is accomplished by using a second reflective surface formed at a second bias angle to totally internally reflect the optical signal in the desired direction. The first bias angle and the second bias angle may be determined to achieve any suitable exit angle for the optical signal. In this respect, the bias angles of the first reflective surface and the second reflective surface may be chosen to minimize insertion losses and crosstalk and to maximize coupling efficiency between the optical fiber and any other optical components while still achieving a selected exit angle for the optical signal.
In one embodiment of the present invention, the first reflective surface and the second reflective surface may be formed such that the optical signal exits the optical fiber at an exit angle that is ninety degrees from the longitudinal axis of the optical fiber. In this respect, any optical component may be coupled to the optical fiber using any suitable alignment techniques and devices, such as any standard V-groove device that is limited to the (110) directions in (100) silicon.
Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims.