US5004447A
Expired / Lapsed
US
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Low loss semiconductor directional coupler switches including gain method of switching light using same
Assignee: United States Department of the Air Force
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Filing: 1989-09-06
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Granted: 1991-04-02
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Expires: 2009-09-06
Abstract
Abstract In multiple quantum well directional couplers, non-centralized input and output legs, occupying major portions of the switches, are continuously forward biased, to produce sufficient gain in light intensity therein to overcome losses in the centralized portions, to in turn provide a transparent (ODB loss) two-by-two coupler switch. Short segments of the centralized coupling portion occupying minor portions of the switches, are switched between forward bias states and zero bias states to provide light beam switching. Thus these switches employ both carrier gain and carrier refraction. The large changes in the index of refraction enable extremely short, low loss, switches to be fabricated and cascaded if desired. A second group of less preferred switches employ solely the carrier refraction effect, by injecting carriers into the waveguides at high levels, preferably equal to or greater than 1×10 18 /cm 3 .
Inventors
- 👤 Richard A. Soref
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:23
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/1028; H01S5/1032; G; G02; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/3132; G02F1/3133; H01S5/06; H01S5/062; H01S5/06209; H01S5/06213
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
157 words
An interferometric directional coupler switch comprising: (a) a pair of first and second index-guided laser-like multi-layered semiconductor waveguides for switching light beams having a wavelength on the longer wave side of the gain spectrum of said waveguides, said light beams traveling along a longitudinal axis of said coupler switch; (b) a centralized first waveguide portion wherein the first and second waveguides are in close coupling relationship and at least one non-centralized waveguide portion wherein said waveguides are not in a closely coupled relationship, said centralized and non-centralized waveguide portions being tandemly positioned along said longitudinal axis; (c) first forward biasing means for intermittently injecting sufficient carriers through said centralized first waveguide portion for producing a carrier refraction and gain effect therein great enough to change the state of said directional coupler switch; and (d) second forward biasing means for continuously injecting sufficient carriers through said non-centralized waveguide portion for producing carrier induced gain of light intensity therein.
Claim 2
Dependent Claim
157 words
An interferometric directional coupler switch comprising: (a) a pair of first and second index-guided laser-like multi-layered semiconductor waveguides for switching light beams having a wavelength on the longer wave side of the gain spectrum of said waveguides, said light beams traveling along a longitudinal axis of said coupler switch; (b) a centralized first waveguide portion wherein the first and second waveguides are in close coupling relationship and at least one non-centralized waveguide portion wherein said waveguides are not in a closely coupled relationship, said centralized and non-centralized waveguide portions being tandemly positioned along said longitudinal axis; (c) first forward biasing means for intermittently injecting sufficient carriers through said centralized first waveguide portion for producing a carrier refraction and gain effect therein great enough to change the state of said directional coupler switch; and (d) second forward biasing means for continuously injecting sufficient carriers through said non-centralized waveguide portion for producing carrier induced gain of light intensity therein.
Claim 3
Dependent Claim
42 words
Directional coupler switch of claim 1 wherein said directional coupler is of the delta-beta type and said first forward biasing means includes electrode means positioned on top of said waveguides at said centralized coupling portion for changing the index of refraction thereof.
Claim 4
Dependent Claim
44 words
Directional coupler of claim 1 wherein said directional coupler is of the delta K type and said first biasing means includes electrode means positioned between said pair of waveguides in said centralized coupling portion for changing the coupling coefficient of said directional coupler switch.
Claim 5
Dependent Claim
22 words
The directional switch of claim 1 wherein said index-guided waveguides have two to ten quantum wells in a waveguide core portion thereof.
Claim 6
Dependent Claim
22 words
The directional switch of claim 2 wherein said index-guided waveguides have two to ten quantum wells in a waveguide core portion thereof.
Claim 7
Dependent Claim
22 words
The directional switch of claim 3 wherein said index-guided waveguides have two to ten quantum wells in a waveguide core portion thereof.
Claim 8
Dependent Claim
52 words
The directional switch of claims 1, 2, 3, 4, 5 or 6, wherein said first and second forward biasing means inject carriers into said waveguides having a density of 1×10 18 /cm 3 or more, and wherein said centralized waveguide portion has an interaction coupling length of about 500 micrometers or less.
Claim 9
Dependent Claim
55 words
The directional coupler switch of claims 1, 2, 3, 4, 5 or 6 wherein said first forward biasing means includes first electrode means positioned on minor portions of said coupler switch and said second forward biasing means includes second electrode means positioned on major portions of said coupler switch for continuously injecting said carriers therein.
Claim 10
Dependent Claim
49 words
The directional coupler switch of claim 7 wherein said first forward biasing means includes first electrode means positioned on minor portions of said coupler switch and said second forward biasing means includes second electrode means positioned on major portions of said coupler switch for continuously injecting said carriers therein.
Claim 11
Dependent Claim
31 words
The directional coupler switch of claim 7 wherein said forward biasing means comprises electrode means for selectively applying a voltage of one polarity or zero volts to said directional coupler switch.
Claim 12
Dependent Claim
31 words
The directional coupler switch of claim 8 wherein said forward biasing means comprises electrode means for selectively applying a voltage of one polarity or zero volts to said directional coupler switch.
Claim 13
Dependent Claim
31 words
The directional coupler switch of claim 9 wherein said forward biasing means comprises electrode means for selectively applying a voltage of one polarity or zero volts to said directional coupler switch.
Claim 14
Dependent Claim
134 words
Method of switching light beams comprising the steps of: (a) providing an interferometric two-by-two directional coupler switch having a pair of index guided laser-like multi-layered semiconductor waveguides in close coupling relationship in a centralized waveguide coupling portion for supporting two modes and converging and diverging non-centralized waveguide portions for supporting one mode, said directional coupler switch being capable of assuming a two-fold bar or cross state and further including forward biasing means for intermittently injecting sufficient carriers through said centralized semiconductor waveguide portions for producing a carrier refraction effect therein great enough to change the state of said directional couper switch; and (b) passing light beams, through said directional coupler switch having a wavelength longer than the absorption edge wavelength at zero bias and also longer than the gain wing wavelength at forward bias.
Claim 15
Dependent Claim
134 words
Method of switching light beams comprising the steps of: (a) providing an interferometric two-by-two directional coupler switch having a pair of index guided laser-like multi-layered semiconductor waveguides in close coupling relationship in a centralized waveguide coupling portion for supporting two modes and converging and diverging non-centralized waveguide portions for supporting one mode, said directional coupler switch being capable of assuming a two-fold bar or cross state and further including forward biasing means for intermittently injecting sufficient carriers through said centralized semiconductor waveguide portions for producing a carrier refraction effect therein great enough to change the state of said directional couper switch; and (b) passing light beams, through said directional coupler switch having a wavelength longer than the absorption edge wavelength at zero bias and also longer than the gain wing wavelength at forward bias.
Claim 16
Dependent Claim
39 words
The method of claim 13 including the step of applying a voltage of a given polarity to said forward biasing means to change the index of refraction thereof to a sufficient degree to change the state of said switch.
Claim 17
Independent Claim
22 words
The method of claims 13 or 14 wherein said index-guided waveguides have two to ten quantum wells in a core portion thereof.
Claim 18
Dependent Claim
47 words
The method of claim 13 or 14 wherein said first and second forward biasing means inject carriers into said waveguides having a density of 1×10 18 /cm 3 or more, and wherein said centralized waveguide portion has an interaction coupling length of about 500 micrometers or less.
Claim 19
Dependent Claim
45 words
The method of claim 15 wherein said first and second forward biasing means inject carriers into said waveguides having a density of 1×10 18 /cm 3 or more, and wherein said centralized waveguide portion has an interaction coupling length of about 500 micrometers or less.
Claim 20
Dependent Claim
42 words
The coupler switch of claim 1 comprising second and third waveguide portions having converging and diverging waveguides in said second and third waveguide portions respectively, said first, second and third waveguide portions being tandemly positioned along the length of said longitudinal axis.
Claim 21
Dependent Claim
20 words
The coupler of claim 18 wherein said second biasing means covers substantially all of said second and third waveguide portions.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-01 | 1994-10-01 | 1995-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-01 | 1998-10-01 | 1999-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-01 | 2002-10-01 | 2003-04-02 | $7700.00 | Window Closed / Lapsed |