Method and apparatus for fabricating microstructured optical fibers

Patent metadata

Field	Value
Publication number	US-2016357174-A1
Application number	US-201514731562-A
Country	US
Kind code	A1
Filing date	Jun 5, 2015
Priority date	Jun 5, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

Prior to fabrication of an optical fiber with desired optical properties, a preform geometry is determined dependent upon a fiber geometry that possesses the desired optical properties. The desired geometry may contain a large number of channels. The processor determines the preform geometry by tracking backwards in time the parameters of a set of conformal mappings that describe the cross section of the fiber. Some of the drawing process parameters may be specified, while other parameters may be determined along with the preform geometry. The determined preform geometry may be used to fabricate the required preform. Using this preform, the determined drawing process parameters may be used to draw the desired fiber.

First claim

1 . A method for determining input values for a microstructured optical fiber fabrication system that draws a microstructured optical fiber fabrication system from a heated preform, where the microstructured optical fiber contains a plurality of pores, the method comprising:
representing flow in the heated preform material by a stream function of the form:
ψ= Im[ z ƒ ( z ,τ)+ g ( z ,τ)],

in which z is a position within the fiber, ƒ(z)−ƒ 1 z+◯(1/z),

g
′



(
z
)

=

∑

k
=
1

N
-
1





g
k



z
k

+

◯


(

1
/
z

)

and the function ƒ 1 is related to the far-field pressure p and vorticity ω, as follows from the relation

4


f
′



(

z
,
τ

)

=

p
μ

-
ω

;

for each pore of the plurality of pores, representing a time varying boundary z n (ζ,τ) of the pore as a conformal mapping of a unit disc |ζ|<1, where ζ is a complex parameter and the conformal mapping given by:

z
n



(

ζ
,
τ

)

=

Z
n



(
τ
)

+

a

n
,

-
1



(
τ
)

ζ

+

∑

k
=
1

N
-
1





a

n
,
k



(
τ
)



ζ
k

,

in which τ is a time variable, n is an index of the pore, Z n (τ) is a centroid position of the n th pore, a n,−1 (τ) and a n,k (τ) are time varying parameters that describe the shape of the pore, and N is an integer greater than 2, and wherein Re{z n (ζ,τ)}≡x n (ζ,τ) denotes the x-coordinate of the pore boundary and Im{z n (ζ,τ)}≡y n (ζ,τ) denotes the y-coordinate of the pore boundary;
for each pore of the plurality of pores, selecting first values a n,−1 (τ 0 ), a n,k (τ 0 ) and Z n (τ 0 ) corresponding to a first value of the time variable τ 0 ;
dependent upon the first value for the plurality of pores, determining, in a hardware processor, second values a n,−1 (τ 1 ), a n,k (τ 1 ) and Z n (τ 1 ) corresponding to a second value of the time variable τ 1 ; and
outputting the second values, a n,−1 (τ 1 ), a n,k (τ 1 ) and Z n (τ 1 ), to the microstructured optical fiber fabrication system.

2 . The method of claim 1 , wherein τ 1 <τ 0 such that the n th pore in fabricated fiber has a boundary given by

z
n



(

ζ
,

τ
0

)

=

Z
n



(

τ
0

)

+

a

n
,

-
1



(

Assignees

• Imp Innovations Ltd

Inventors

• Buchak Peter
• CROWDY Darren
• Stokes Yvonne Marie
• Chen Michael James
• Ebendorff-Heidepriem Heike

Classifications

• B29D11/00663

  Production of light guides · CPC title

• C03B37/02781 Primary

  Hollow fibres, e.g. holey fibres · CPC title

• C03B2203/42

  Photonic crystal fibres, e.g. fibres using the photonic bandgap PBG effect, microstructured or holey optical fibres · CPC title

• C03B37/0253

  Controlling or regulating (for glass fibre manufacture in general C03B37/07) · CPC title

• C03B2205/40

  Monitoring or regulating the draw tension or draw rate · CPC title