US 5,179,605 A · Optical interconnection device

Abstract

An optical interconnection device suitable for an N.times.N' coupler as used, for example, in a local area network, comprises diffraction means in the form of a body having a refractive index which varies spatially and periodically in one plane of the body. The arrangement is such that light incident upon the body in the plane and at a predetermined angle will be refracted to emerge at a plurality of discrete angles determined by the spatially varying refractive index. The incident light is distributed substantially equally among the plurality of output refracted beams and substantially all of said incident light is coupled to the plurality of refracted beams. The diffraction means comprises a cylindrical body, and the device further comprises two arrays of optical sources and/or receivers. The arrays are disposed at opposite faces, respectively, of the body, each of the optical receivers having an optical axis aligned with one of the discrete angles. A perfect shuffle network may comprise a plurality of nodes interconnected by such a coupler, each node comprising a transmitter operable at several wavelengths a receiver, and means for determining whether a received signal is to be relayed and, if so, the appropriate transmission wavelength.

Claims21

Dependent claims

An optical interconnection device comprising a volume Bragg diffraction means, a first plurality (m) of optical elements spaced apart in a plane and a second plurality (m') of optical elements spaced apart in the same plane, said volume Bragg diffraction means extending in said plane between said first plurality of elements and said second plurality of elements, the first plurality of elements corresponding to diffraction orders of light beams from individual ones of said second plurality of elements and the second plurality of elements corresponding to diffraction orders of light beams from individual ones of said first plurality of elements, said diffraction means having its refractive index varying spatially according to the expression:

##EQU58## where x and z are coordinates of said plane;
K*.sub.m,m' is the spatial frequency vector;
m and m' take on integer values equal to the first plurality and second plurality, respectively;
.DELTA..sub.m,m' is the coefficient of coupling between m and m';
and
r is the spaced vector,
the spatial frequency vector K*.sub.m,m' being determined according to the expression ##EQU59## k is the optical wave vector and ##EQU60## where .theta. .sub.0 is the angle between adjacent diffraction orders;
and ##EQU61## where d is the thickness of the volume diffraction means in a direction transverse to said plane.

5 more elements

Apparatus for making a volume diffraction means for an optical interconnection device for coupling light beams between a first plurality (m) of optical elements spaced apart in a plane and a second plurality (m') spaced apart in said plane, by exposing a body of photorefractive material to radiation from a plurality of mutually coherent light sources to record resulting interference patterns such that the refractive index of the body, after exposure, will vary spatially according to the expression:

##EQU63## where x and z are coordinates of said plane;
K*.sub.m,m' is the spatial frequency vector;
m and m' take on integer values equal to the first plurality and second plurality, respectively;
.DELTA..sub.m,m' is the coefficient of coupling between m and m';
and
r is the space vector, the spatial frequency vector K*.sub.m,m' being determined according to the expression ##EQU64## k is the optical wave vector and ##EQU65## where .theta..sub.v is the angle between adjacent diffraction orders;
and ##EQU66## where d is the thickness of the volume diffraction means in a direction transverse to the common plane, the apparatus comprising at least one pair of optical elements for emitting said radiation and means for controlling said optical elements to emit radiation simultaneously and for a predetermined length of time from different pairs of predetermined positions, the positions of each pair being spaced apart in a common plane through said body, one said position corresponding to a diffraction order for a light beam from the other position of said pair.

4 more elements

A method of making a volume Bragg diffraction means for an optical interconnection device for coupling a first plurality of optical elements spaced apart in a plane and a second plurality of optical elements spaced apart in said plane, the first plurality of optical elements corresponding to diffraction orders of light beams from individual ones of the second plurality of optical elements and the second plurality of optical elements corresponding to diffraction orders of light beams from individual ones of the first plurality of optical elements, such that the refractive index of the body, after exposure, will vary spatial according to the expression:

##EQU67## where x and z are coordinates of said plane;
K*.sub.m,m' is the spatial frequency vector;
m and m' take on integer values equal to the first plurality and second plurality, respectively;
.DELTA..sub.m,m' is the coefficient of coupling between m and m';
and
r is the space vector,
the spatial frequency vector K*.sub.m,m' being determined according to the expression ##EQU68## k is the optical wave vector and ##EQU69## where .theta..sub.0 is the angle between adjacent diffraction orders;
and ##EQU70## where d is the thickness of the volume diffraction means, said method comprising the steps of:
(i) exposing a body of photorefractive material for a predetermined length of time to radiation from a pair of coherent light sources of the same wavelength, one source disposed at a first predetermined position corresponding to an element of said first plurality and the other disposed at a position corresponding to a diffraction order thereof, to record a first interference pattern;
and
(ii) exposing the body for a second predetermined length of time to radiation from said one source at said first predetermined position and a second source at a position corresponding to a different one of the second plurality of diffraction orders;
(iii) repeating step (ii) for each different one of the second plurality of diffraction orders;
(iv) repeating steps (i), (ii) and (iii) with said one source at positions corresponding to each of the first plurality of elements.

10 more elements

Dependencies are inferred from the claim text.

Optical interconnection device

Life of this patent

Optical interconnection device

Life of this patent

Abstract

Claims21