US5502783A
Expired / Lapsed
US
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Polarization independent optical directional coupler wavelength tunable filters/receivers
Assignee: Nortel Networks Ltd
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Filing: 1994-08-18
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Granted: 1996-03-26
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Expires: 2014-08-18
Abstract
Abstract A polarization independent tunable filter/receiver for optical communications. The tunable filter, operating as a directional coupler, has three waveguides including a central, feedguide and a pair of branch waveguides. Through either electro-optic effects or free carrier injection, the TM and TE polarization modes of the central wavelength can be coupled from the feedguide to the appropriate branch guide. The separated modes can be either detected independently or reunited in phase for further processing.
Inventors
- 👤 Chi Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:36
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/12007; G02B6/12004; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/3132; G02F1/3133; G02F2203/00; G02F2203/05; G02F2203/055; G02F2203/06
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
126 words
A polarization independent optical directional coupler wavelength tunable filter comprising: a first waveguide to receive and transfer therethrough an optical signal having a plurality of wavelength channels each having transverse electric (TE) and transverse magnetic (TM) polarization modes; a second waveguide having at least a portion thereof in juxtaposition to said first waveguide; a third waveguide having at least a portion thereof in juxtaposition to said first waveguide; and wavelength tuning means associated with said waveguides to selectively couple said transverse electric polarization mode of one of said plurality of wavelength channels from said first waveguide to said second waveguide and to selectively couple said transverse magnetic polarization mode of said one of said plurality of wavelength channels from said first waveguide to said third waveguide.
Claim 2
Dependent Claim
126 words
A polarization independent optical directional coupler wavelength tunable filter comprising: a first waveguide to receive and transfer therethrough an optical signal having a plurality of wavelength channels each having transverse electric (TE) and transverse magnetic (TM) polarization modes; a second waveguide having at least a portion thereof in juxtaposition to said first waveguide; a third waveguide having at least a portion thereof in juxtaposition to said first waveguide; and wavelength tuning means associated with said waveguides to selectively couple said transverse electric polarization mode of one of said plurality of wavelength channels from said first waveguide to said second waveguide and to selectively couple said transverse magnetic polarization mode of said one of said plurality of wavelength channels from said first waveguide to said third waveguide.
Claim 3
Dependent Claim
43 words
A tunable filter as defined in claim 1 having a monolithic, integrated receiver in each of said second and third waveguides to absorb said transverse electric polarization mode and said transverse magnetic polarization mode of said one of said plurality of wavelength channels.
Claim 4
Dependent Claim
33 words
A tunable filter/receiver as defined in claim 2, each of the second and third waveguides having an integrated photodetector located at a position downstream from the portion in juxtaposition to the first waveguide.
Claim 5
Dependent Claim
32 words
A tunable filter as defined in claim 3, each of the second and third waveguides having an integrated low-pass filter between the photodetector and the portion in juxtaposition to said first waveguide.
Claim 6
Dependent Claim
24 words
A tunable filter/receiver as defined in claim 2, further including an optical amplifier in at least one of said first, second or third waveguides.
Claim 7
Dependent Claim
38 words
A tunable filter/receiver as defined in claim 2, said transverse electric and transverse magnetic polarization modes of said one of said plurality of wavelength channels coupled to said second and third waveguides being codirectional with said optical signal.
Claim 8
Dependent Claim
38 words
A tunable filter/receiver as defined in claim 2, said transverse electric and transverse magnetic polarization modes of said one of said plurality of wavelength channels coupled to said second and third waveguides being contradirectional to said optical signal.
Claim 9
Dependent Claim
45 words
A tunable filter as defined in claim 5, said second and third waveguides having gratings which reflect said transverse electric and transverse magnetic polarization modes of said one of said plurality of wavelength channels in opposite direction to said optical signal in said first waveguide.
Claim 10
Dependent Claim
14 words
A tunable filter/receiver as defined in claim 2, fabricated in a semiconductor material structure.
Claim 11
Dependent Claim
21 words
A tunable filter as defined in claim 9, said semiconductor structure comprising layers of III-V alloy compounds on a III-V substrate.
Claim 12
Dependent Claim
16 words
A tunable filter as defined in claim 9, said semiconductor structure comprising layers of II-VI materials.
Claim 13
Dependent Claim
16 words
A tunable filter as defined in claim 9, said semiconductor structure comprising layers of IV materials.
Claim 14
Dependent Claim
19 words
A tunable filter as defined in claim 10, said III-V alloy compound being InGaAsP and said substrate being InP.
Claim 15
Dependent Claim
19 words
A tunable filter as defined in claim 10, said III-V alloy compound being AlGaAs and said substrate being GaAs.
Claim 16
Dependent Claim
21 words
A tunable filter as defined in claim 1, fabricated in a class of electro-optic material including Lithium Niobate (LiNbO 3 ).
Claim 17
Dependent Claim
13 words
A tunable filter as defined in claim 1, fabricated in a polymer material.
Claim 18
Dependent Claim
19 words
A tunable filter as defined in claim 1, fabricated in a class of photo-refractive materials including silica and glass.
Claim 19
Dependent Claim
21 words
A tunable filter as defined in claim 1, said transverse electric (TE) and transverse magnetic (TM) polarization modes being randomly polarized.
Claim 20
Dependent Claim
26 words
A tunable filter as defined in claim 18, said wavelength tuning means including means on said second and said third waveguides to selectively inject tuning current.
Claim 21
Dependent Claim
28 words
A tunable filter as defined in claim 19, wherein the refractive index of said first waveguide is different than the refractive index of said second and third waveguides.
Claim 22
Dependent Claim
27 words
A tunable filter as defined in claim 20, wherein the difference in refractive indexes is due to a difference in composition of the material in respective waveguides.
Claim 23
Dependent Claim
25 words
A tunable filter as defined in claim 20, wherein the difference in effective refractive indexes is due to a difference in geometry between respective waveguides.
Claim 24
Dependent Claim
19 words
A tunable filter as defined in claim 22, wherein the geometric difference relates to thickness differentials between respective waveguides.
Claim 25
Dependent Claim
19 words
A tunable filter as defined in claim 22, wherein the geometric difference relates to width differentials between respective waveguides.
Claim 26
Dependent Claim
47 words
A tunable filter as defined in claim 1, wherein the length of the portion of the second and third waveguides in juxtaposition to said first waveguide is dependent on the coupling strength of the TE and TM modes to be coupled to said second and third waveguides.
Claim 27
Dependent Claim
27 words
A tunable filter as defined in claim 18, said wavelength tuning means including means on said second and third waveguide to selectively reverse bias p-n junctions therein.
Claim 28
Dependent Claim
31 words
A tunable filter as defined in claim 26, said reverse bias to said p-n junctions results in an electro-optic effect which increases the refractive index of said second and third waveguides.
Claim 29
Dependent Claim
23 words
A tunable filter as defined in claim 19, wavelength tuning means further including a periodic grating on at least one of said waveguides.
Claim 30
Dependent Claim
32 words
A tunable filter as defined in claim 19, said wavelength tuning means further including a periodic grating on each of said second and third waveguides wherein period of the gratings is different.
Claim 31
Dependent Claim
45 words
A tunable filter as defined in claim 1, wherein the separations between the first and second, first and third waveguides in the juxtaposition area are dependent on the coupling strength of the TE and TM modes to be coupled to said second and third waveguides.
Claim 32
Dependent Claim
17 words
A tunable filter as defined in claim 1, wherein the first, second and third waveguides are coplanar.
Claim 33
Dependent Claim
23 words
A tunable filter as defined in claim 1, wherein the second and third waveguides are coplanar and separated vertically from the first waveguide.
Claim 34
Dependent Claim
32 words
A tunable filter as defined in claim 1, further including Y-branch coupler uniting the second and third waveguides at a position downstream from the portion thereof in juxtaposition to the first waveguide.
Claim 35
Dependent Claim
33 words
A tunable filter as defined in claim 33, further having a Y-branch coupler uniting the second and third waveguides at a position upstream from the portion thereof in juxtaposition to the first waveguide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-03-26 | 1999-09-25 | 2000-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-26 | 2003-09-25 | 2004-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-26 | 2007-09-25 | 2008-03-26 | $7700.00 | Window Closed / Lapsed |