Passive star coupler
AssigneeAmerican Telephone and Telegraph Company, AT&T Bell Laboratories
InventorsHerwig W. Kogelnik, Adel A. M. Saleh
Life of this patent
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Abstract
A star coupler for a single-mode-fiber optical local area network which reduces the amount of fiber required by a factor of two and diminishes the number of components by one-half. This savings in fiber and components is effected by "reflecting" signals which appear at various locations of the network back toward the input ports. The arrangement forms a broadcast-type of local area network where a message transmitted by any user can be received by all users.
Claims3
A single mode fiber passive star coupler having a number of ports n equal to an arbitrary multiple (l) of a perfect square (m.sup.2) of an arbitrary number (m);
- characterized by ml transmissive m.times.m stars, the ports i of the l transmissive m.times.m stars of l-group i, i=1,2, . . . , m, are coupled together via a reflective l star;
- and the ports i of the l transmissive m.times.m stars of l group #j,i,j=1,2 . . . , m, i.noteq.j, are coupled via(m-1) transmissive l.times.l stars to ports j of the l transmissive m.times.m stars of the l-group #i.
A single mode fiber passive star coupler having a number of ports equal to an arbitrary multiple (l) of a perfect square (m.sup.2) of an arbitrary number (m) characterized by a first group of transmissive m.times.m star coupler;
- a second group of transmissive m.times.m star coupler, transmissive l.times.l star interposed between selected output ports of the first group of transmissive stars and selected output ports of the second group of transmissive stars, a first reflective star coupled to selective ports of the first group of transmissive star couplers, and a second reflective star coupled to selective ports of the second group of transmissive star couplers.
Dependencies are inferred from the claim text.