Optical filter or multiplexer/demultiplexer

Patent metadata

Field	Value
Publication number	US-8938137-B2
Application number	US-201113637830-A
Country	US
Kind code	B2
Filing date	Mar 18, 2011
Priority date	Mar 31, 2010
Publication date	Jan 20, 2015
Grant date	Jan 20, 2015

Abstract

An optical filter or multiplexer/demultiplexer, including a plurality of optical waveguides forming a planar structure. Each optical waveguide has a total length including one or more first segments with a first width and at least one or more second segments with a second width, the first width being larger than the second width. The sum of lengths of the one or more first segments in each optical waveguide is larger than half the total length of the waveguide.

First claim

The invention claimed is:

1. An optical device, comprising:
a plurality of optical waveguides forming a planar structure, each optical waveguide having a total length; wherein at least one optical waveguide comprises one or more first segments and at least one or more second segments;
wherein in said at least one optical waveguide each first segment has a first width and a first length and each second segment has a second width a second length and the first width is larger than the second width; and
wherein a sum of lengths of the one or more second segments in said at least one optical waveguide is shorter than half the total length of the waveguide; and wherein said sum of lengths of the one or more second segments in said at least one optical waveguide is less than about 500 times of a wavelength of an optical signal travelling within said at least one waveguide.

2. The optical device of claim 1 wherein a total length of the second segments in at least one waveguide is less than about 100 times of a wavelength of an optical signal travelling within said at least one waveguide.

3. The optical device of claim 1 , wherein at least one waveguide has no second segment.

4. The optical device of claim 1 , wherein the sum of lengths of the one or more first segments in each optical waveguide is larger than 75% of the total length of the waveguide.

5. The optical device of claim 1 , wherein at least one optical waveguide has one or more third segments, the third segments having a third width smaller than the first width and different from the first width and the second width.

6. The optical device of claim 1 , wherein said plurality of waveguides are positioned successively, forming said planar structure and wherein a total length of the first segments and the total length of the second segments vary from one waveguide to a successive waveguide according to the following relationships:



Δ
⁢

⁢

L
a



=

Δ
⁢

⁢

L

eff
⁡

(
i
)

*

ⅆ

n
b

ⅆ
T

n
a

⁢

ⅆ

n
b

ⅆ
T

-

n
b

⁢

ⅆ

n
a

ⅆ
T



Δ
⁢

⁢

L
b



=

Δ
⁢

⁢

L

eff
⁡

(
i
)

*

ⅆ

n
a

ⅆ
T

n
a

⁢

ⅆ

n
b

ⅆ
T

-

n
b

⁢

ⅆ

n
a

ⅆ
T

where ΔL eff(i) is an effective optical path length difference between the two successive waveguides, n a and n b are indices of refraction of the first segments and the second segments respectively, T is the temperature, |ΔL a | is an absolute value of a difference in the total length of the first segments between the two successive waveguides and |ΔL b | is an absolute value the difference in the total length of the second segments between the same successive waveguides.

7. The optical device of claim 1 , wherein said plurality of waveguides are positioned successively, forming said planar structure and wherein a ratio between a first product and a second product is between 0.8 and 1.2, wherein the first product is obtained from the following formula:

ⅆ

n
a

ⅆ
T

*



Δ
⁢

⁢

L

Assignees

• Doerr Christopher
• Alcatel Lucent

Inventors

• Doerr Christopher

Classifications

• G02B6/29398

  Temperature insensitivity · CPC title

• G02B6/10

  of the optical waveguide type (G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00) · CPC title

• G02B6/29352

  in a light guide · CPC title

• G02B6/12011

  characterised by the arrayed waveguides, e.g. comprising a filled groove in the array section · CPC title

• G02B6/12 Primary

  of the integrated circuit kind (electric integrated circuits H10B, H10D84/00 - H10D89/00, H10F19/00, H10F39/00, H10H29/00, H10K19/00, H10K39/00, H10K59/00, H10N19/00, H10N39/00, H10N59/00, H10N69/00, H10N79/00, H10N89/00) · CPC title