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US 4,904,042 AGranted
N.times.N optical star coupler
AssigneesAmerican Telephone and Telegraph Company, AT&T Bell Laboratories
InventorCorrado Dragone
Life of this patent
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Abstract
An efficient N.times.N star optical coupler suitable for mass production in integrated form is disclosed. The coupler can be realized using silicon technology to form a dielectric coupler slab and two arrays of strip waveguides all on a single glass substrate. Power transfer betwen the two arrays is accomplished through radiation in the dielectric slab with theoretical efficiency exceeding 30% under optimized conditions.
Claims9
A device for simultaneously transmitting optical signals representative of intelligence from N sources to N' detectors, comprising
- (a) a medium capable of transmitting optical radiation with loss less than 1 db/cm;
- (b) an array of N injection means of aperture a.sub.i for injecting, into a substantially two dimensional plane within the said medium, optical radiation;
- and
- (c) an array of N' extraction means of aperture a'.sub.i, for extracting transmitted optical radiation from the said medium;
- the invention characterized in that
- (1) the injection and extraction means comprise single mode waveguides;
- (2) the array of N injection means are located along a segment of a circle with radius of curvature substantially equal to R, the length, L, of the segment given substantially by L=.SIGMA.a;
- (3) the array of N' extraction means are located along a segment of a circle of radius of curvature substantially equal to R, the length, L', of the segment given substantially by L'=.SIGMA.a';
- (4) the center of curvature of the circle whose segment determines the configuration of each array lies substantially on the circle segment which defines the other array;
- (5) the axis of symmetry of each of the elements is substantially directed to the center of curvature of the circle whose segment defines that array;
- and
- (6) the distance R is selected to substantially maximize the transmission between marginal injection elements and marginal extraction elements.
9 more elements
Dependencies are inferred from the claim text.