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EP0444817A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Optical multiplexer/demultiplexer

Assignee: AT&T Inc
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Filing: 1991-02-20
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Granted: —
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Expires: 2011-02-20
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Abstract

Abstract This invention is an optical Multiplexer/Demultiplexer, built from a plurality of optical waveguides (106-108, 101-105). Each waveguide (101-105) differs in length from its neighboring waveguide by a predetermined amount. The waveguides are strongly coupled to one another at their respective ends, and substantially uncoupled therebetween, allowing for high efficiency. As the wave propagates along the tapered region of the waveguides of waveguide array (115), it is gradually transformed into five separate uncoupled waves, with such tranformation causing near zero higher order mode generation. Each of the five uncoupled waves will then propagate along its respective waveguide until reaching waveguide array (113). At waveguide array (113), the five waves are gradually coupled back into a single propagating wavefront, which emanates toward waveguide array (114). Since l is an integer multiple of λ₀, the constant phase difference φ between adjacent waveguides is preserved. Thus the wave emanating from each of the waveguides of waveguide array (113) is phase shifted by φ from the wave emanating from its neighboring waveguide. The five waves will combine to produce a single wavefront which propagates in a direction that corresponds exactly to the direction along waveguide array (112) from which the wave was launched. More particularly, a wave launched from waveguide (106) will be directed by waveguide array (113) toward waveguide (109), since waveguides (106) and (109) are disposed in corresponding positions of their respective waveguide arrays (112) and (114). Similarly, waves which are launched from waveguides (107) or (108), will be directed by waveguide array (113) at waveguides (110) and (111), respectively. This is due to the fact that waveguides (107) and (110) are located in corresponding positions of their respective waveguide arrays (112) and (114), as are waveguides (108) and (111).

Inventors

  • 👤 Corrado Dragone

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-10 01:46
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/12007; G02B6/12009; G02B6/12011; G02B6/12016; G02B6/24; G02B6/26; G02B6/28; G02B6/2804

Claims Analysis

Total Claims: 16
Claim 1
Independent Claim 89 words
An optical multiplexer/demultiplexer comprising: a plurality of N optical waveguides, each waveguide including a first end for receiving optical energy and a second end for transmitting optical energy, each waveguide further being of a predetermined different length substantially equal to I + nl, where I is a predetermined initial length, n is an integer such that 0≦n≦N-1, and l is a predetermined value greater than zero, the waveguides being substantially coupled to each other at their respective first ends, and at their respective second ends, and substantialy uncoupled therebetween.
Claim 2
Dependent Claim 47 words
The optical multiplexer/demultiplexer of claim 1 wherein the first ends of each waveguide are arranged into a first waveguide array to substantially define a first arc, and wherein the second ends of the waveguides are arranged into a second waveguide array, to substantially define a second arc.
Claim 3
Dependent Claim 21 words
The optical multiplexer/demultiplexer of claim 2 wherein the first end and the second end of each waveguide includes a tapered portion.
Claim 4
Dependent Claim 136 words
The optical multiplexer/demultiplexer of claim 3 wherein the tapered portion includes a first end and a second end and wherein at least one of said arrays includes a series of refractive profiles, thereby defining the shape of the taper, each refractive profile comprising a first order Fourier coefficient, each first order Fourier coefficient substantially equal to: where 2γ is an angle defining a central Brillioun zone associated with the array, ϑ B is an arbitrary angle less than or equal to γ, p(y) is substantially equal to z is a distance from the second end of the waveguides to the refractive profile, b is a distance which an outer surface of each waveguide would have to be extended from the second end to become tangent to an adjacent waveguide, and F r = 1-F t .
Claim 5
Dependent Claim 22 words
The optical multiplexer/demultiplexer of claim 4 wherein at least one of said waveguides comprises a delay element for increasing its path length.
Claim 6
Dependent Claim 61 words
The optical multiplexer/demultiplexer of claim 5 further comprising an input array, including: a plurality of waveguides, each including a first end for receiving optical energy, and a second end for launching the optical energy, said second ends being arranged to substantially define a third arc, said third arc defining a portion of a circle which is centered along said first arc.
Claim 7
Dependent Claim 61 words
An optical multiplexer/demultiplexer of claim 6 further comprising an output array, including: a plurality of waveguides, each including a first end for receiving optical energy, and a second end for launching the optical energy, said second ends being arranged to substantially define a fourth arc, said fourth arc defining a portion of a circle which is centered along said second arc.
Claim 8
Dependent Claim 154 words
An optical multiplexer/demultiplexer comprising: a plurality of optical waveguides, each having a first end for receiving optical energy and a second end for launching the optical energy, and a predetermined length, means for injecting optical energy into the first ends, and a plurality of receivers, each for receiving optical energy which emanates from the second ends, wherein the length of each waveguide is such that optical energy emanates from the second ends at a predetermined angle that varies with wavelength, each of the receivers is associated with a predetermined wavelength and is positioned at the predetermined angle relative to the second ends of the waveguides, such that substantially all optical energy emanated from the second ends of the optical waveguides in a predetermined frequency band centered at the associated wavelength emanates at the predetermined angle, and the waveguides are substantially coupled at their first ends and at their second ends, and substantially uncoupled therebetween.
Claim 9
Dependent Claim 47 words
The optical multiplexer/demultiplexer of claim 8 wherein the first ends of the waveguides are arranged into a first waveguide array to substantially define a first arc, and wherein the second ends of the waveguides are arranged into a second waveguide array, to substantially define a second arc.
Claim 10
Dependent Claim 152 words
The optical multiplexer/demultiplexer of claim 9 wherein each of the waveguides in at least one of said arrays includes a predetermined tapered portion, the tapered portion having a first end and a second end and wherein the at least one of said arrays includes a series of refractive profiles, thereby defining the shape of the taper each refractive profile comprising a fist order Fourier coefficient, each first order Fourier coefficient substantially equal to: where 2γ is an angle defining a central Brillioun zone associated with the array, ϑ B is an arbitrary angle less than or equal to γ, p(y) is substantially equal to z is a distance from the second end of the waveguides to the refractive profile, b is a distance which an outer surface of each waveguide would have to be extended from the second end to become tangent to an adjacent waveguide, and F r =1-F t .
Claim 11
Dependent Claim 22 words
The optical multiplexer/demultiplexer of claim 10 wherein at least one of said waveguides comprises a delay element for increasing its path length.
Claim 12
Dependent Claim 61 words
The optical multiplexer/demultiplexer of claim 11 further comprising an input array, including: a plurality of waveguides, each including a first end for receiving optical energy, and a second end for launching the optical energy, said second ends being arranged to substantially define a third arc, said third arc defining a portion of a circle which is centered along said first arc.
Claim 13
Dependent Claim 61 words
An optical multiplexer/demultiplexer of claim 12 further comprising an output array, including: a plurality of waveguides, each including a first end for receiving optical energy, and a second end for launching the optical energy, said second ends being arranged to substantially define a fourth arc, said fourth arc defining a portion of a circle which is centered along said second arc.
Claim 14
Dependent Claim 23 words
An optical multiplexer/demultiplexer according to claim 13 wherein at least one of said waveguides comprises a delay element for increasing its path length.
Claim 15
Dependent Claim 63 words
An optical multiplexing arrangement according to clam 14 further comprising an input array, including: a plurality of waveguides, each including a first end for receiving optical energy, and a second end for launching the optical energy, said second ends being arranged to substantially define a third arc, said third arc defining a portion of a circle which is centered along said first arc.
Claim 16
Dependent Claim 63 words
An optical multiplexing arrangement according to claim 15 further comprising an output array, including: a plurality of waveguides, each including a first end for receiving optical energy, and a second end for launching the optical energy, said second ends being arranged to substantially define a fourth arc, said fourth arc defining a portion of a circle which is centered along said second arc.

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