US6445839B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical wavelength-division-multiplexed cross-connect incorporating optically controlled optical switch
Assignee: Leland Stanford Junior University
•
Filing: 1999-11-05
•
Granted: 2002-09-03
•
Expires: 2019-11-05
Abstract
Abstract A semiconductor device for modulating an optical power light beam with an optical signal light beam contains a detector diode for absorbing the signal beam and a quantum well modulator diode for absorbing the power beam. Both diodes are reverse biased, allowing for absorption of the power beam at photon energies below the band gap energy of the quantum well layer. Absorption of the signal beam creates carriers that screen the field in the detector diode, lowering the bias voltage. Because top and bottom layers of the entire structure are made to be highly conductive, overall voltage is fixed, leading to a simultaneous change of voltage in the modulator diode, altering absorption by electroabsorption mechanisms. In a first embodiment, the diodes are oriented such that decreased voltage in the detector diode leads to decreased voltage in the modulator diode; the device is used as an optically controlled optical switch. Alternately, the voltage in the modulator diode increases, and the device is used as a gated photodetector. The optically controlled optical switch may be incorporated into an optical cross-connect for use in wavelength-division-multiplexed systems. The cross-connect contains an array of switches, and can transfer signal information between beams of different wavelength. A given set of input signals can be selectively switched to a given set of output signals of different wavelength.
Inventors
- 👤 David A. B. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:18
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/015; G02F1/017; G02F1/01708; B; B82; B82Y; B82Y20/00; G02F2/00; G02F2/004; H; H04; H04Q; H04Q11/00; H04Q11/0001; H04Q11/0005; G02F1/01716; H04Q2011/0037; H04Q2011/0041
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
256 words
A semiconductor device for modulating an optical power light beam at a first wavelength with an optical signal light beam at a second wavelength, said semiconductor device comprising: a) a detector diode comprising an upper contact layer; a detector absorbing layer for absorbing said optical signal light beam, and an upper cladding layer, said detector absorbing layer being located between said upper contact layer and said upper cladding layer; b) a modulator diode comprising said upper cladding layer, a modulator absorbing layer for absorbing said optical power light beam, and a lower cladding layer, said modulator absorbing layer being located between said upper cladding layer and said lower cladding layer and having an electric field-dependent absorption coefficient; c) a first voltage source connected across said upper contact layer and said upper cladding layer for applying a reverse bias voltage V d to said detector diode; d) a second voltage source connected across said upper cladding layer and said lower cladding layer for applying a reverse bias voltage V m to said modulator diode; e) an electric contact to said upper cladding layer for allowing a net charge to flow into and out of said semiconductor device for supporting diffusive electrical conduction in said upper cladding layer; wherein said optical signal light beam absorbed in said detector absorbing layer causes a local change in said detector diode reverse bias voltage V d and causes a related local change in said modulator diode reverse bias voltage V m thus altering said absorption coefficient of said modulator absorbing layer.
Claim 2
Dependent Claim
256 words
A semiconductor device for modulating an optical power light beam at a first wavelength with an optical signal light beam at a second wavelength, said semiconductor device comprising: a) a detector diode comprising an upper contact layer; a detector absorbing layer for absorbing said optical signal light beam, and an upper cladding layer, said detector absorbing layer being located between said upper contact layer and said upper cladding layer; b) a modulator diode comprising said upper cladding layer, a modulator absorbing layer for absorbing said optical power light beam, and a lower cladding layer, said modulator absorbing layer being located between said upper cladding layer and said lower cladding layer and having an electric field-dependent absorption coefficient; c) a first voltage source connected across said upper contact layer and said upper cladding layer for applying a reverse bias voltage V d to said detector diode; d) a second voltage source connected across said upper cladding layer and said lower cladding layer for applying a reverse bias voltage V m to said modulator diode; e) an electric contact to said upper cladding layer for allowing a net charge to flow into and out of said semiconductor device for supporting diffusive electrical conduction in said upper cladding layer; wherein said optical signal light beam absorbed in said detector absorbing layer causes a local change in said detector diode reverse bias voltage V d and causes a related local change in said modulator diode reverse bias voltage V m thus altering said absorption coefficient of said modulator absorbing layer.
Claim 3
Dependent Claim
66 words
The semiconductor device of claim 1 , wherein: a) said optical power light beam has a power beam diameter and propagates into a region of said modulator absorbing layer; b) said optical signal light beam propagates into a region of said detector absorbing layer; and c) said region of said modulator absorbing layer is within a short distance from said region of said detector absorbing layer.
Claim 4
Dependent Claim
25 words
The semiconductor device of claim 2 , wherein said region of said detector absorbing layer is substantially above said region of said modulator absorbing layer.
Claim 5
Dependent Claim
26 words
The semiconductor device of claim 2 , wherein said short distance from said region of said detector absorbing layer is less than said power beam diameter.
Claim 6
Dependent Claim
24 words
The semiconductor device of claim 2 , wherein said short distance from said region of said detector absorbing layer is less than 20 μm.
Claim 7
Dependent Claim
39 words
The semiconductor device of claim 2 , wherein said upper contact layer and said lower cladding layer have a sufficiently high electrical conductivity that a voltage between said upper contact layer and said lower cladding layer is substantially constant.
Claim 8
Dependent Claim
31 words
The semiconductor device of claim 6 , wherein said upper cladding layer has a predetermined resistivity chosen to control a rate of said diffusive electrical conduction in said upper cladding layer.
Claim 9
Dependent Claim
40 words
The semiconductor device of claim 6 , wherein a resistance per square of said upper cladding layer is substantially larger than a resistance per square of said upper contact layer and a resistance per square of said lower cladding layer.
Claim 10
Dependent Claim
28 words
The semiconductor device of claim 1 , further comprising means for collecting a photocurrent produced by absorption of said optical power light beam by said modulator absorbing layer.
Claim 11
Dependent Claim
18 words
The semiconductor device of claim 1 , wherein said modulator absorbing layer comprises at least one quantum well.
Claim 12
Dependent Claim
333 words
An optical cross-connect for modulating a set of M optical power light beams with a set of N optical signal light beams to generate a set of M optical output beams, said cross-connect having an array of optical switches for modulating at least one of said optical power light beams with at least one of said optical signal light beams to generate one of said optical output beams, each of said optical switches comprising: a) a detector diode comprising an upper contact layer, a detector absorbing layer for absorbing at least one of said optical signal light beams, and an upper cladding layer, said detector absorbing layer being located between said upper contact layer and said upper cladding layer; b) a first voltage source connected across said upper contact layer and said upper cladding layer for applying a reverse bias voltage V d to said detector diode; c) a modulator diode comprising said upper cladding layer, a modulator absorbing layer for absorbing at least one of said optical power light beams, and a lower cladding layer, said modulator absorbing layer being located between said upper cladding layer and said lower cladding layer and having an electric field-dependent absorption coefficient; d) a second voltage source connected across said upper cladding layer and said lower cladding layer for applying a reverse bias voltage V m to said modulator diode; e) an electric contact to said upper cladding layer for allowing a net charge to flow into and out of said optical cross-connect for supporting diffusive electrical conduction in said upper cladding layer; such that in each of said optical switches the absorption of at least one of said optical signal light beams by said detector absorbing layer causes a local change in said detector diode reverse bias voltage V d and causes a related local change in said modulator diode reverse bias voltage V m thus altering the absorption coefficient of said modulator absorbing layer and modulating at least one of said power light beams.
Claim 13
Dependent Claim
333 words
An optical cross-connect for modulating a set of M optical power light beams with a set of N optical signal light beams to generate a set of M optical output beams, said cross-connect having an array of optical switches for modulating at least one of said optical power light beams with at least one of said optical signal light beams to generate one of said optical output beams, each of said optical switches comprising: a) a detector diode comprising an upper contact layer, a detector absorbing layer for absorbing at least one of said optical signal light beams, and an upper cladding layer, said detector absorbing layer being located between said upper contact layer and said upper cladding layer; b) a first voltage source connected across said upper contact layer and said upper cladding layer for applying a reverse bias voltage V d to said detector diode; c) a modulator diode comprising said upper cladding layer, a modulator absorbing layer for absorbing at least one of said optical power light beams, and a lower cladding layer, said modulator absorbing layer being located between said upper cladding layer and said lower cladding layer and having an electric field-dependent absorption coefficient; d) a second voltage source connected across said upper cladding layer and said lower cladding layer for applying a reverse bias voltage V m to said modulator diode; e) an electric contact to said upper cladding layer for allowing a net charge to flow into and out of said optical cross-connect for supporting diffusive electrical conduction in said upper cladding layer; such that in each of said optical switches the absorption of at least one of said optical signal light beams by said detector absorbing layer causes a local change in said detector diode reverse bias voltage V d and causes a related local change in said modulator diode reverse bias voltage V m thus altering the absorption coefficient of said modulator absorbing layer and modulating at least one of said power light beams.
Claim 14
Dependent Claim
33 words
The optical cross-connect of claim 11 , wherein each of said optical signal light beams is of a different wavelength and each of said optical power light beams is of a different wavelength.
Claim 15
Dependent Claim
22 words
The optical cross-connect of claim 11 , wherein said array of optical switches comprises N rows and M columns of optical switches.
Claim 16
Dependent Claim
36 words
The optical cross-connect of claim 11 , further comprising a set of optical waveguides for delivering said optical power light beams to said optical switches and for delivering said optical output beams from said optical switches.
Claim 17
Dependent Claim
20 words
The optical cross-connect of claim 11 , wherein each of said modulator absorbing layers comprises at least one quantum well.
Claim 18
Dependent Claim
74 words
The optical cross-connect of claim 11 , wherein: a) each of said optical power light beams has a power beam diameter and propagates into a region of one of said modulator absorbing layers; b) each of said optical signal light beams propagates into a region of one of said detector absorbing layers; and c) said region of said modulator absorbing layer is within a short distance from said region of said detector absorbing layer.
Claim 19
Dependent Claim
25 words
The optical cross-connect of claim 16 , wherein said region of said detector absorbing layer is substantially above said region of said modulator absorbing layer.
Claim 20
Dependent Claim
18 words
The optical cross-connect of claim 16 , wherein said short distance is less than said power beam diameter.
Claim 21
Dependent Claim
16 words
The optical cross-connect of claim 16 , wherein said short distance is less than 20 μm.
Claim 22
Dependent Claim
28 words
The optical cross-connect of claim 11 , wherein said upper cladding layer has a predetermined resistivity chosen to control said diffusive electrical conduction in said upper cladding layer.
Claim 23
Dependent Claim
40 words
The optical cross-connect of claim 20 , wherein a resistance per square of said upper cladding layer is substantially larger than a resistance per square of said upper contact layer and a resistance per square of said lower cladding layer.
References Cited (Backward Citations)
US4525687A
Cited
US4737003A
Cited
US4546244A
Cited
US5339370A
Cited
US5434700A
Cited
US5504609A
Cited
US5608566A
Cited
US5825517A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-09-02 | 2006-03-04 | 2006-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-09-02 | 2010-03-04 | 2010-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-09-02 | 2014-03-04 | 2014-09-03 | $7700.00 | Window Closed / Lapsed |