Fused fiber-optic tapers in optical wireless receivers and method
A compounded light-focusing optical element is configured to focus light, and the compounded light-focusing optical element includes a body having a first, flat, end face and a second, curved end face, the second, curved end face being opposite to the first, flat end face, and plural optical fibers extending through the body, from the first, flat end face to the second, curved end face. The plural optical fibers are fused to each other to form the body, and end faces of the plural optical fibers, corresponding to the second, curved end face, are pointing in different directions.
1 . A compounded light-focusing optical element configured to focus light, the compounded light-focusing optical element comprising:
a body having a first, flat end face, a parallel fibers region, a cylindrical region, and a second, curved end face, the second, curved end face being opposite to the first, flat end face, and the parallel fibers region and the cylindrical region being located between the first, flat end face and the second, curved end face; and
plural optical fibers extending through the body, from the first, flat end face to the second, curved end face,
wherein the plural optical fibers are tapered toward the first, flat end face and fused to each other to form the body, wherein each fiber comprises a core and a cladding,
wherein end faces of the plural optical fibers, corresponding to the second, curved end face, are pointing in different directions,
wherein the plural optical fibers are parallel to each other within the parallel fibers region,
wherein each of the parallel fibers region and the cylindrical region extends along a longitudinal axis of the body, and
wherein the cylindrical region has a constant cross-sectional diameter along the longitudinal axis.
2 . The compounded light-focusing optical element of claim 1 , wherein the second, curved end face is convex.
3 . The compounded light-focusing optical element of claim 1 , wherein the second, curved end face is concave.
4 . The compounded light-focusing optical element of claim 1 , wherein the body includes a non-parallel optical fibers region where not all the plural optical fibers are parallel to each other.
5 . The compounded light-focusing optical element of claim 1 , further comprising:
a wavelength up/down-converting layer or phosphor, for changing a wavelength of an incoming light to a different wavelength, and located over at least one of the first, flat end face and the second, curved end face of the body.
6 . The compounded light-focusing optical element of claim 1 , wherein the first, flat end face is sized to have a diameter substantially equal to a bundle of optical fibers, which are optically coupled to the first, flat end face.
7 . An optical wireless communication system comprising:
a transmitter node configured to generate an optical beam having encoded information; and
a receiver node configured to receive the optical beam and to extract the encoded information,
wherein the receiver node includes a non-flat compounded light-focusing optical element configured to focus the optical beam, the non-flat compounded light-focusing optical element including,
a body having a first, flat end face, a parallel fibers region, a cylindrical region, and a second, curved end face, the second, curved end face being opposite to the first, flat end face, and the parallel fibers region and the cylindrical region being located between the first, flat end face and the second, curved end face; and
plural optical fibers extending through the body, from the first, flat end face to the second, curved end face,
wherein the plural optical fibers are tapered toward the first, flat end face and fused to each other to form the body, wherein each fiber comprises a core and a cladding,
wherein end faces of the plural optical fibers, corresponding to the second, curved end face, are pointing in different directions,
wherein the plural optical fibers are parallel to each other within the parallel fibers region,
wherein each of the parallel fibers region and the cylindrical region extends along a longitudinal axis of the body, and
wherein the cylindrical region has a constant cross-sectional diameter along the longitudinal axis.
8 . The system of claim 7 , wherein the second, curved end face is convex.
9 . The system of claim 7 , wherein the second, curved end face is concave.
10 . The system of claim 7 , wherein the body includes a non-parallel optical fibers region where not all the plural optical fibers are parallel to each other.
11 . The system of claim 7 , further comprising:
a wavelength up/down-converting layer or phosphor, for changing a wavelength of an incoming light to a different wavelength, and located over at least one of the first, flat end face and the second, curved end face of the body.
12 . The system of claim 7 , wherein the first, flat end face is sized to have a diameter substantially equal to a bundle of optical fibers, which are optically coupled to the first, flat end face.
13 . The system of claim 7 , wherein the receive node comprises:
a photodetector having an active area, the active area being configured to receive the optical beam and transform the optical beam into an electric current; and
electronics configured to process the electric current and extract the encoded information.
14 . The system of claim 13 , further comprising:
a flat compounded light-focusing optical element connected in series with the non-flat compounded light-focusing optical element,
wherein the flat compounded light-focusing optical element has both end faces flat.
15 . The system of claim 14 , wherein a first flat face of the flat compounded light-focusing optical element is optically coupled to the active area, and a second flat face of the flat compounded light-focusing optical element is optically coupled to the first, flat end face of the non-flat compounded light-focusing optical element.
16 . The system of claim 7 , wherein each of the transmitter node and the receiver node uses visible light or infrared light or ultraviolet light.
17 . A method for optical wireless communication, the method comprising:
generating, at a transmitter node, an optical beam;
encoding information into the optical beam;
transmitting in a wireless manner the encoded information with the optical beam;
receiving, at a non-flat compounded light-focusing optical element of a receiver node, the optical beam;
focusing the optical beam, with the non-flat compounded light-focusing optical element, to a photodetector; and
extracting the encoded information from the optical beam,
wherein the non-flat compounded light-focusing optical element has a body including a first, flat end face, a parallel fibers region, a cylindrical region, and a second, curved end face, the second, curved end face being opposite to the first, flat end face, the parallel fibers region and the cylindrical region being located between the first, flat end face and the second, curved end face, and plural optical fibers extending through the body, from the first, flat end face to the second, curved end face, the plural optical fibers being tapered toward the first, flat end face and fused to each other to form the body, wherein each fiber comprises a core and a cladding,
wherein end faces of the plural optical fibers, corresponding to the second, curved end face, are pointing in different directions,
wherein the body includes a parallel fibers region in which the plural optical fibers are parallel to each other,
wherein each of the parallel fibers region and the cylindrical region extends along a longitudinal axis of the body,
wherein the cylindrical region has a constant cross-sectional diameter along the longitudinal axis.
18 . The method of claim 17 , wherein the second, curved end face is convex.