US4946250A — Compact wavelength filter integrated to a single-…

Claim 1

Independent Claim 114 words

A wavelength filter integrated to a single-mode optical fiber capable of propagating a light signal and comprising a longitudinal outer jacket enveloping the optical fiber, the said fiber being stripped of its jacket on a given length thereof to form a non-jacketed length of optical fiber, said non-jacketed fiber length being formed with first and second concatenated biconical tapers separated from each other by a given distance and each having a given profile, wherein the said given distance and the given profile of each biconical taper can be chosen to enable transmission through the filter of a first, predetermined wavelength of the propagated light signal while stopping a second, predetermined wavelength of said signal.

Claim 2

Dependent Claim 114 words

A wavelength filter integrated to a single-mode optical fiber capable of propagating a light signal and comprising a longitudinal outer jacket enveloping the optical fiber, the said fiber being stripped of its jacket on a given length thereof to form a non-jacketed length of optical fiber, said non-jacketed fiber length being formed with first and second concatenated biconical tapers separated from each other by a given distance and each having a given profile, wherein the said given distance and the given profile of each biconical taper can be chosen to enable transmission through the filter of a first, predetermined wavelength of the propagated light signal while stopping a second, predetermined wavelength of said signal.

Claim 3

Dependent Claim 16 words

The wavelength filter of claim 1, wherein said first and second biconical tapers have identical profiles.

Claim 4

Dependent Claim 18 words

The wavelength filter of claim 1, in which the said first and second biconical tapers have different profiles.

Claim 5

Dependent Claim 23 words

The wavelength filter of claim 1, wherein a non-jacketed section of said optical fiber is interposed between the first and second biconical tapers.

Claim 6

Dependent Claim 69 words

The wavelength filter of claim 4, in which said given distance separating the first and second tapers is given by the following relation: δβL=(2n+1)π where: L is said given distance separating the first and second tapers; δβ is a difference between propagation constants of two light propagation modes beating in said non-jacketed section of optical fiber interposed between the first and second biconical tapers; and n is an integer.

Claim 7

Dependent Claim 104 words

The wavelength filter of claim 4, in which normalized light power τ(λ) transmitted through the said filter at a given wavelength λ is approximated by the following relation: τ(λ)=T(λ)T'(λ)+R(λ)R'(λ)+2√T(λ)T'(λ)R(λ)R'(λ) cos(δβL) where: T(λ) is the normalized light power transmitted through the first taper at the wavelength λ; T'(λ) is the normalized light power transmitted through the second taper at the wavelength λ; R(λ)=1-T(λ) R'(λ)=1-T'(λ) δβ is a difference between propagation constants of two light propagation modes beating in said non-jacketed section of optical fiber interposed between the first and second biconical tapers; and L is said given distance separating said first and second concatenated tapers.

Claim 8

Dependent Claim 65 words

The wavelength filter of claim 6, in which the terms T(λ) and T'(λ) are given by an expression of the form: ##EQU4## where: R 0 is the amplitude of the spectral response of the corresponding taper; Λ is the period of the wavelength response; and λ p is a reference wavelength at which light power transmitted through the first and second tapers, respectively, is maximum.

Claim 9

Dependent Claim 114 words

A wavelength filter integrated to a single-mode optical fiber capable of propagating a light signal and comprising a longitudinal outer jacket enveloping the optical fiber, the said fiber being stripped of its jacket on a given length thereof to form a non-jacketed length of optical fiber, said non-jacketed fiber length being formed with at least two concatenated biconical tapers separated from each other by a given distance and each having a given profile, wherein the said given distance and the given profile of each biconic taper can be chosen to enable transmission through the filter of a first, predetermined wavelength of the propagated light signal while stopping a second, predetermined wavelength of said signal.

Claim 10

Dependent Claim 114 words

A wavelength filter integrated to a single-mode optical fiber capable of propagating a light signal and comprising a longitudinal outer jacket enveloping the optical fiber, the said fiber being stripped of its jacket on a given length thereof to form a non-jacketed length of optical fiber, said non-jacketed fiber length being formed with at least two concatenated biconical tapers separated from each other by a given distance and each having a given profile, wherein the said given distance and the given profile of each biconic taper can be chosen to enable transmission through the filter of a first, predetermined wavelength of the propagated light signal while stopping a second, predetermined wavelength of said signal.

Claim 11

Independent Claim 212 words

A method of integrating a wavelength filter to a single-mode optical fiber capable of propagating a light signal and comprising a longitudinal outer jacket enveloping the optical fiber, said method comprising the steps of: (a) stripping said optical fiber of its jacket on a given length thereof to form a non-jacketed length of optical fiber; (b) heating said non-jacketed fiber length at a first location thereof up to a point at which the optical fiber becomes viscous; (c) producing a longitudinal tension in said fiber to stretch said heated first location and thereby form a first biconical taper having a given profile; (d) heating said non-jacketed fiber length at a second location thereof spaced apart from said first location up to a point at which the optical fiber becomes viscous; and (e) producing a longitudinal tension in said fiber to stretch said heated second location and thereby form a second biconical taper also having a given profile and separated from said first taper by a given distance; wherein the said given distance and the given profile of each of said first and second tapers can be adjusted to enable transmission through the filter of a first, predetermined wavelength of the propagated light signal while stopping a second, predetermined wavelength of said signal.

Claim 12

Independent Claim 212 words

A method of integrating a wavelength filter to a single-mode optical fiber capable of propagating a light signal and comprising a longitudinal outer jacket enveloping the optical fiber, said method comprising the steps of: (a) stripping said optical fiber of its jacket on a given length thereof to form a non-jacketed length of optical fiber; (b) heating said non-jacketed fiber length at a first location thereof up to a point at which the optical fiber becomes viscous; (c) producing a longitudinal tension in said fiber to stretch said heated first location and thereby form a first biconical taper having a given profile; (d) heating said non-jacketed fiber length at a second location thereof spaced apart from said first location up to a point at which the optical fiber becomes viscous; and (e) producing a longitudinal tension in said fiber to stretch said heated second location and thereby form a second biconical taper also having a given profile and separated from said first taper by a given distance; wherein the said given distance and the given profile of each of said first and second tapers can be adjusted to enable transmission through the filter of a first, predetermined wavelength of the propagated light signal while stopping a second, predetermined wavelength of said signal.

Claim 13

Dependent Claim 26 words

The method of claim 9 further comprising the step of etching the non-jacketed fiber length with an acid before carrying out said steps (b) to (e).

Claim 14

Dependent Claim 20 words

The method of claim 9, further comprising the step of pre-tapering non-jacketed fiber length carrying out steps (b) to (e).

Claim 15

Dependent Claim 47 words

The method of claim 9, further comprising the steps of: propagating a monochromatic light signal through the optical fiber; and stopping stretching of said heated first location after occurrence of a number N, N being an integer, of oscillations in the amplitude of said propagated monochromatic signal.

Claim 16

Dependent Claim 36 words

The method of claim 12, further comprising the step of stopping stretch of said heated second location after occurrence of a N', N' being an integer, of oscillations in the amplitude of said propagated monochromatic signal.

Claim 17

Dependent Claim 18 words

The method of claim 13, wherein at least of the numbers N and N' is equal to 0.

Claim 18

Dependent Claim 19 words

The method of claim 13, wherein at least one of the numbers N and N' is equal to 1.

Claim 19

Dependent Claim 20 words

The method of claim 13, in which at least one of the numbers N and N' is equal to 2.

Claim 20

Dependent Claim 14 words

The method of claim 13, in which said numbers N and N' are different.

Claim 21

Dependent Claim 14 words

The method of claim 13, in which said numbers N and N' are equal.

Claim 22

Dependent Claim 25 words

The method of claim 9, further comprising the step of tapering a non-jacketed section of said optical fiber separating the first and second biconical tapers.

Claim 23

Dependent Claim 43 words

The method of claim 9, further comprising the steps of: propagating a white light signal through the optical fiber; and analysing wavelength responses of the filter after step (c) and after step (e) to determine whether said filter has desired wavelength filtering characteristics.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-08-06	1994-02-05	1994-08-07	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-08-06	1998-02-05	1998-08-07	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-08-06	2002-02-05	2002-08-07	$7700.00	Window Closed / Lapsed

Compact wavelength filter integrated to a single-mode optical fiber

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