Polyhedral integrated and free space optical interconnection

DETAILED DESCRIPTION OF THE INVENTION FIG.
1 shows a prior art communications system using holographic optical elements.
A substantially planar plate 100 is optically transmissive.
Holographic optical elements 115, 116, 117, 118 connect to the plate.
A first optical transmitter 131 connects with element 118.
A second optical transmitter 133 connects with element 116.
A first optical receiver 134 connects with element 115.
A second optical receiver 132 connects with element 117.
The elements all have internal holograms that route optical signals to accomplish a desired interconnection.
For example, element 118 can convert a signal from transmitter 131 into a first guided wave with a distinct propagation angle.
The first guided signal propagates within the plate, reaching element 115.
Element 115 then routes the incident signal to receiver 134.
Similarly, element 116 can convert an optical signal from transmitter 133 into a second guided wave.
The second guided wave propagates through the substrate, reaching element 117.
Element 117 routes the signal to receiver 132.
Different arrangements of elements and different internal holograms can accomplish different interconnections.
The transmitters and receivers must all connect to the same planar substrate.
FIG.
2 shows a sectional view of one embodiment of the present invention.
The figure shows four optically transmissive plates 200, 201, 202, 203, arrayed in a polyhedron (the section through the polyhedron shows a square).
The space contained within the polyhedron can be free space or can be a material with known refractive properties.
Holographic optical elements connect with the plates.
Each element can contain multiple holograms, including reflective and transmissive holograms.
The holograms within the elements route optical signals to accomplish the desired interconnection.
For example, a hologram in element 222 converts an optical signal from transmitter 231 into a first guided signal in substrate 200.
The first guided signal travels via total internal reflection in the substrate 200 to element 214