US4877304A — Few-mode/single-mode fiber

Claim 1

Independent Claim 217 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) -- τ j , the difference between |d(Vb)/dV| j , the normalized delay time of the jth mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V j+1 c , where j is an integer up to 2 and represents the highest order mode that is capable of propagating through said fiber, 0 represents the fundamental mode, b is the propagation constant and V is the normalized frequency, and V j+1 c is the normalized cutoff frequency of the j+1 mode, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 2

Dependent Claim 217 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) -- τ j , the difference between |d(Vb)/dV| j , the normalized delay time of the jth mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V j+1 c , where j is an integer up to 2 and represents the highest order mode that is capable of propagating through said fiber, 0 represents the fundamental mode, b is the propagation constant and V is the normalized frequency, and V j+1 c is the normalized cutoff frequency of the j+1 mode, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 3

Dependent Claim 32 words

An optical fiber in accordance with claim 1 wherein said core comprises a plurality of radially disposed regions, the refractive index profile of at least one of said regions being radially graded.

Claim 4

Dependent Claim 64 words

An optical fiber in accordance with claim 1 wherein said core includes at least one annular region of depressed refractive index, the inner radius a i of the innermost of said at least one region being greater than zero and the maximum radius a 0 of the outermost of said at least one region of depressed refractive index being less than the radius a.

Claim 5

Dependent Claim 87 words

An optical fiber in accordance with claim 1 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by at least two regions of increasing radius having the following refractive indices and radii: (n 2 , a a ) and (n 3 , a 3 ), respectively, wherein a 3 is greater than a 2 , a 2 is greater than a 1 , and n 1 and n 3 are greater than n 2 .

Claim 6

Dependent Claim 17 words

An optical fiber in accordance with claim 4 wherein n 1 is greater than n 3 .

Claim 7

Dependent Claim 17 words

An optical fiber in accordance with claim 4 wherein n 3 is greater than n 1 .

Claim 8

Dependent Claim 17 words

An optical fiber in accordance with claim 4 wherein n 2 is greater than n 0 .

Claim 9

Dependent Claim 17 words

An optical fiber in accordance with claim 4 wherein n 2 is less than n 0 .

Claim 10

Dependent Claim 39 words

An optical fiber in accordance with claim 8 wherein said core comprises a further region having a radius a 4 which is greater than a 3 and a refractive index n 4 which is less than n 0 .

Claim 11

Dependent Claim 17 words

An optical fiber in accordance with claim 9 wherein n 4 is equal to n 2 .

Claim 12

Dependent Claim 87 words

An optical fiber in accordance with claim 1 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by at least two regions of increasing radius having the following refractive indices and radii: (n 2 , a 2 ) and (n 3 , a 3 ), respectively, wherein a 3 is greater than a 2 , a 2 is greater than a 1 , and n 2 is greater than n 1 and n 3 .

Claim 13

Dependent Claim 17 words

An optical fiber in accordance with claim 11 wherein n 1 is equal to n 3 .

Claim 14

Dependent Claim 18 words

An optical fiber in accordance with claim 11 wherein n 1 is not equal to n 3 .

Claim 15

Dependent Claim 61 words

An optical fiber in accordance with claim 1 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by at least one region having a refractive index n 2 and radius a 2 and wherein n 1 is greater n 0 and n 0 is greater than n 2 .

Claim 16

Dependent Claim 62 words

An optical fiber in accordance with claim 1 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by a region having a refractive index n 2 and a radius a 2 , and wherein n 1 is greater than n 2 and n 2 is greater than n 0 .

Claim 17

Dependent Claim 36 words

An optical fiber in accordance with claim 15 wherein said core further comprises a third region having a refractive index less than n 2 and n 0 and having a radius greater than a 2 .

Claim 18

Dependent Claim 40 words

An optical fiber in accordance with claim 1 wherein said fiber is characterized in that it comprises core refractive index means for enabling the propagation of a single mode signal with zero total dispersion near the zero material dispersion wavelength.

Claim 19

Dependent Claim 69 words

An optical fiber in accordance with claim 17 wherein said fiber is characterized in that said core and said layer of transparent cladding material each comprise silica or silica and a dopant which modifies the refractive index thereof, and wherein said fiber comprises refractive index means for enabling the propagation of a single mode signal with zero total dispersion at a wavelength within the range of about 1285-1335 nanometers.

Claim 20

Dependent Claim 192 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) -- τ j , the difference between |d(V/b)/dV| j , the normalized delay time of the jth mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V j+1 c , where j is an integer up to 2 and represents the highest order mode that propagates through said fiber, 0 represents the fundamental mode, b is the propagation constant and V is the normalized frequency, and V j+1 c is the normalized cutoff frequency of the j+1 mode, and (b) said fiber exhibits a single-mode dispersion of less than 5 ps/nm-km.

Claim 21

Dependent Claim 192 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) -- τ j , the difference between |d(V/b)/dV| j , the normalized delay time of the jth mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V j+1 c , where j is an integer up to 2 and represents the highest order mode that propagates through said fiber, 0 represents the fundamental mode, b is the propagation constant and V is the normalized frequency, and V j+1 c is the normalized cutoff frequency of the j+1 mode, and (b) said fiber exhibits a single-mode dispersion of less than 5 ps/nm-km.

Claim 22

Dependent Claim 59 words

An optical fiber in accordance with claim 19 wherein said fiber is characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that said fiber is capable of propagating a single mode signal with zero total dispersion near the zero material dispersion wavelength.

Claim 23

Dependent Claim 88 words

An optical fiber in accordance with claim 20 wherein said fiber is characterized in that said core and said layer of transparent cladding material each comprise silica or silica and a dopant which modifies the refractive index thereof, and wherein the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that said fiber is capable of propagating a single mode signal with zero total dispersion at a wavelength within the range of about 1285-1335 nanometers.

Claim 24

Dependent Claim 32 words

An optical fiber in accordance with claim 19 wherein said core comprises a plurality of radially disposed regions, the refractive index profile of at least one of said regions being radially graded.

Claim 25

Dependent Claim 64 words

An optical fiber in accordance with claim 19 wherein said core includes at least one annular region of depressed refractive index, the inner radius a i of the innermost of said at least one region being greater than zero and the maximum radius a 0 of the outermost of said at least one region of depressed refractive index being less than the radius a.

Claim 26

Dependent Claim 87 words

An optical fiber in accordance with claim 19 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by at least two regions of increasing radius having the following refractive indices and radii: (n 2 , a 2 ) and (n 3 , a 3 ) respectively, wherein a 3 is greater than a 2 , a 2 is greater than a 1 , and n 1 and n 3 are greater than n 2 .

Claim 27

Dependent Claim 87 words

An optical fiber in accordance with claim 19 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by at least two regions of increasing radius having the following refractive indices and radii: (n 2 , a 2 ) and (n 3 , a 3 ), respectively, wherein a 3 is greater than a 2 , a 2 is greater than a 1 , and n 2 is greater than n 1 and n 3 .

Claim 28

Dependent Claim 62 words

An optical fiber in accordance with claim 19 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by at least one region having a refractive index n 2 and radius a 2 and wherein n 1 is greater than n 0 and n 0 is greater than n 2 .

Claim 29

Dependent Claim 62 words

An optical fiber in accordance with claim 19 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by a region having a refractive index n 2 and a radius a 2 , and wherein n 1 is greater than n 2 and n 2 is greater than n 0 .

Claim 30

Dependent Claim 136 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) said fiber is capable of propagating two or more modes at a first wavelength range with a bandwidth greater than 1 GHz-km, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 31

Dependent Claim 136 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) said fiber is capable of propagating two or more modes at a first wavelength range with a bandwidth greater than 1 GHz-km, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 32

Dependent Claim 59 words

An optical fiber in accordance with claim 28 wherein said fiber is characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that said fiber is capable of propagating a single mode signal with zero total dispersion near the zero material dispersion wavelength.

Claim 33

Dependent Claim 88 words

An optical fiber in accordance with claim 29 wherein said fiber is characterized in that said core and said layer of transparent cladding material each comprise silica or silica and a dopant which modifies the refractive index thereof, and wherein the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that said fiber is capable of propagating a single mode signal with zero total dispersion at a wavelength within the range of about 1285-1335 nanometers.

Claim 34

Dependent Claim 46 words

An optical fiber in accordance with claim 28 wherein Δτ j is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V j+1 c , where V j+1 c is the normalized cutoff frequency of the j+1 mode.

Claim 35

Dependent Claim 32 words

An optical fiber in accordance with claim 28 wherein said core comprises a plurality of radially disposed regions, the refractive index profile of at least one of said regions being radially graded.

Claim 36

Dependent Claim 64 words

An optical fiber in accordance with claim 28 wherein said core includes at least one annular region of depressed refractive index, the inner radius a i of the innermost of said at least one region being greater than zero and the maximum radius a 0 of the outermost of said at least one region of depressed refractive index being less than the radius a.

Claim 37

Dependent Claim 87 words

An optical fiber in accordance with claim 28 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by at least two regions of increasing radius having the following refractive indices and radii: (n 2 , a 2 ) and (n 3 , a 3 ), respectively, wherein a 3 is greater than a 2 , a 2 is greater than a 1 , and n 1 and n 3 are greater than n 2 .

Claim 38

Dependent Claim 87 words

An optical fiber in accordance with claim 28 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by at least two regions of increasing radius having the following refractive indices and radii: (n 2 , a 2 ) and (n 3 , a 3 ), respectively, wherein a 3 is greater than a 2 , a 2 is greater than a 1 , and n 2 is greater than n 1 and n 3 .

Claim 39

Dependent Claim 62 words

An optical fiber in accordance with claim 28 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by at least one region having a refractive index n 2 and radius a 2 and wherein n 1 is greater than n 0 and n 0 is greater than n 2 .

Claim 40

Dependent Claim 62 words

An optical fiber in accordance with claim 28 wherein said core includes a centrally located region having a maximum refractive index n 1 and a radius a 1 surrounded by a region having a refractive index n 2 and a radius a 2 , and wherein n 1 is greater than n 2 and n 2 is greater than n 0 .

Claim 41

Dependent Claim 110 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that it comprises core refractive index means for enabling the propagation of (a) a signal having two or more modes in the wavelength range between about 800 and 900 nanometers with a bandwidth greater than 1 GHz, and (b) a single-mode signal with a dispersion of less than 5 ps/nm-km at a wavelength greater than 1250 nanometers.

Claim 42

Dependent Claim 110 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that it comprises core refractive index means for enabling the propagation of (a) a signal having two or more modes in the wavelength range between about 800 and 900 nanometers with a bandwidth greater than 1 GHz, and (b) a single-mode signal with a dispersion of less than 5 ps/nm-km at a wavelength greater than 1250 nanometers.

Claim 43

Dependent Claim 59 words

An optical fiber in accordance with claim 38 wherein said fiber is characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that said fiber is capable of propagating a single mode signal with zero total dispersion near the zero material dispersion wavelength.

Claim 44

Dependent Claim 88 words

An optical fiber in accordance with claim 39 wherein said fiber is characterized in that said core and said layer of transparent cladding material each comprise silica or silica and a dopant which modifies the refractive index thereof, and wherein the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that said fiber is capable of propagating a single mode signal with zero total dispersion at a wavelength within the range of about 1285-1335 nanometers.

Claim 45

Dependent Claim 232 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) said fiber operates at a V-value V o that is up to 1.1 V j+1 c , and -- τ j , the difference between |d(Vb)/dV| j , the normalized delay time of the jth mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V j+1 c , where 0 represents the fundamental mode, j is an integer up to 2 and represents the jth higher order mode which propagates through said fiber, b is the propagation constant, V is the normalized frequency, and V j+1 c is the normalized cutoff frequency of the j+1 mode, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 46

Dependent Claim 232 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) said fiber operates at a V-value V o that is up to 1.1 V j+1 c , and -- τ j , the difference between |d(Vb)/dV| j , the normalized delay time of the jth mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V j+1 c , where 0 represents the fundamental mode, j is an integer up to 2 and represents the jth higher order mode which propagates through said fiber, b is the propagation constant, V is the normalized frequency, and V j+1 c is the normalized cutoff frequency of the j+1 mode, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 47

Dependent Claim 206 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) said fiber operates at a V-value V o that is up to 1.1 V 2 c , the normalized cutoff frequency of the second higher order mode, -- τ j , the difference between |d(Vb)/dV| 1 , the normalized delay time of the first higher order mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V 2 c where b is the propagation constant and V is the normalized frequency, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 48

Dependent Claim 206 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) said fiber operates at a V-value V o that is up to 1.1 V 2 c , the normalized cutoff frequency of the second higher order mode, -- τ j , the difference between |d(Vb)/dV| 1 , the normalized delay time of the first higher order mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V 2 c where b is the propagation constant and V is the normalized frequency, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 49

Dependent Claim 27 words

An optical fiber in accordance with claim 42 wherein said fiber operates at a V-value V o that is no greater than 1.0 V 2 c .

Claim 50

Dependent Claim 207 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) said fiber operates at a V-value V o that is up to 1.1 V 3 c , the normalized cutoff frequency of the third higher order mode, -- τ j , the difference between |d(Vb)/dV| 2 , the normalized delay time of the second higher order mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V 3 c , where b is the propagation constant and V is the normalized frequency, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 51

Dependent Claim 207 words

An optical fiber comprising a core of transparent material having a maximum refractive index n 1 and a radius a, and a layer of transparent cladding material on the outer surface of said core, the refractive index n 0 of said cladding being less than n 1 , said fiber being characterized in that the refractive indices n 1 and n 0 , the radius a, and the refractive index profile of the core are designed such that (a) said fiber operates at a V-value V o that is up to 1.1 V 3 c , the normalized cutoff frequency of the third higher order mode, -- τ j , the difference between |d(Vb)/dV| 2 , the normalized delay time of the second higher order mode and |d(Vb)/dV| 0 , the normalized delay time of the fundamental mode, is less than about 5×10 -2 over a range of V-values equal to about 10% of V near V 3 c , where b is the propagation constant and V is the normalized frequency, and (b) the normalized waveguide dispersion Vd 2 (Vb)/dV 2 is about equal to or less than 0.2 at V-values near V 1 c , the normalized cutoff frequency of the first higher order mode.

Claim 52

Dependent Claim 27 words

An optical fiber in accordance with claim 44 wherein said fiber operates at a V-value V o that is no greater than 1.0 V 3 c .

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-10-30	1993-05-01	1993-10-31	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-10-30	1997-05-01	1997-10-31	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-10-30	2001-05-01	2001-10-31	$7700.00	Window Closed / Lapsed

Few-mode/single-mode fiber

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