US4968110A
Expired / Lapsed
US
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Apparatus and method for optimizing the modulation efficiency of a remotely-located, polarization-sensitive, integrated optic modulator which is addressed with a non-polarization-preserving fiber
Assignee: United States Department of the Navy
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Filing: 1990-01-31
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Granted: 1990-11-06
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Expires: 2010-01-31
Abstract
Abstract An apparatus and method are disclosed for optimizing the modulation efficcy of a remotely-located, polarization-sensitive, integrated optic modulator which is addressed with a non-polarization preserving fiber link. In a preferred embodiment of the invention, the polarization state of an input light beam is changed as a function of first and second control signals that are applied to the polarization controller. The non-polarization preserving fiber link conveys the light beam with the changed polarization state to the integrated optic modulator. The integrated optic modulator modulates the light beam with the changed polarization state as a function of any information signal to develop an intensity modulated optical signal. If no information signal is present, the optical signal from the modulator is not modulated. An output fiber conveys the optical signal from the integrated optic modulator to a locally-positioned detector for detection. In response to this input optical signal, the detector develops a first electrical signal that has a peak-to-peak amplitude proportional to any information signal and a second electrical signal proportional to the mean of the optical signal. This second electrical signal is utilized by a control means to controllably develop first and second control signals which force the polarization controller to change the polarization state of the input light beam so that the light beam at the input of the integrated optic modulator is maintained in a preselected polarization state in order to maintain the modulation efficiency of the integrated optic modulator at its optimum level.
Inventors
- 👤 Catherine H. Bulmer
- 👤 William K. Burns
- 👤 Alan D. Kersey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:41
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25; G; G02; G02B; G02B6/00; G02B6/10; G02B6/105
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
237 words
An apparatus for optimizing the modulation efficiency of a remotely-located, polarization-sensitive, integrated optic modulator device which is addressed with a non-polarization-preserving fiber link, said apparatus comprising: an optical source for providing a carrier light beam; a polarization controller for changing the polarization state of said carrier light beam as a function of first and second control signals applied to said polarization controller, said non-polarization-preserving fiber link conveying said carrier light beam with the changed polarization state to said integrated optic modulator device, said integrated optic modulator device being responsive to any information signal that may be present and to said carrier light beam with the changed polarization state for developing an optical output signal; photodetection means responsive to said optical output signal for developing an electrical signal that has a DC component signal which has an amplitude proportional to the mean of said optical output signal and an AC component signal which has a peak-to-peak amplitude proportional to any information signal that may be present; and control means responsive to said DC component signal for controllably developing said first and second control signals to force said polarization controller to change the polarization state of said carrier light beam so that said carrier light beam at the input of said integrated optic modulator device is maintained in a preselected polarization state in order to maintain the modulation efficiency of said integrated optic modulator device at its optimum level.
Claim 2
Independent Claim
237 words
An apparatus for optimizing the modulation efficiency of a remotely-located, polarization-sensitive, integrated optic modulator device which is addressed with a non-polarization-preserving fiber link, said apparatus comprising: an optical source for providing a carrier light beam; a polarization controller for changing the polarization state of said carrier light beam as a function of first and second control signals applied to said polarization controller, said non-polarization-preserving fiber link conveying said carrier light beam with the changed polarization state to said integrated optic modulator device, said integrated optic modulator device being responsive to any information signal that may be present and to said carrier light beam with the changed polarization state for developing an optical output signal; photodetection means responsive to said optical output signal for developing an electrical signal that has a DC component signal which has an amplitude proportional to the mean of said optical output signal and an AC component signal which has a peak-to-peak amplitude proportional to any information signal that may be present; and control means responsive to said DC component signal for controllably developing said first and second control signals to force said polarization controller to change the polarization state of said carrier light beam so that said carrier light beam at the input of said integrated optic modulator device is maintained in a preselected polarization state in order to maintain the modulation efficiency of said integrated optic modulator device at its optimum level.
Claim 3
Dependent Claim
30 words
The apparatus of claim 1 wherein said photodetection means includes: a photodetector for developing said electrical signal; and an output fiber for conveying said optical output signal to said photodetector.
Claim 4
Dependent Claim
13 words
The apparatus of claim 2 wherein: said output fiber is a non-polarization-preserving fiber.
Claim 5
Independent Claim
243 words
An apparatus comprising: a remotely-located, polarization-sensitive, integrated optic device; an optical source for providing a carrier light beam; a locally-located polarization controller for changing the polarization state of said carrier light beam as a function of first and second control signals applied to said polarization controller; a non-polarization-preserving fiber for conveying said carrier light beam with the changed polarization state from said locally-located polarization controller to said remotely-located, integrated optic device, said integrated optic device being responsive to any information signal that may be present and to said carrier light beam with the changed polarization state for developing an optical output signal; a second fiber for conveying said optical output signal from said remotely-located, integrated optic device; locally-located photodetection means responsive to said optical output signal from said second fiber for developing an electrical signal that has a DC component signal which has an amplitude proportional to the mean of said optical output signal and an AC component signal which has a peak-to-peak amplitude proportional to any information signal that may be present; and control means responsive to said DC component signal for controllably developing said first and second control signals to force said polarization controller to change the polarization state of said carrier light beam so that said carrier light beam at the input of said integrated optic device is maintained in a preselected polarization state in order to maintain the modulation efficiency of said integrated optic device at its optimum level.
Claim 6
Independent Claim
243 words
An apparatus comprising: a remotely-located, polarization-sensitive, integrated optic device; an optical source for providing a carrier light beam; a locally-located polarization controller for changing the polarization state of said carrier light beam as a function of first and second control signals applied to said polarization controller; a non-polarization-preserving fiber for conveying said carrier light beam with the changed polarization state from said locally-located polarization controller to said remotely-located, integrated optic device, said integrated optic device being responsive to any information signal that may be present and to said carrier light beam with the changed polarization state for developing an optical output signal; a second fiber for conveying said optical output signal from said remotely-located, integrated optic device; locally-located photodetection means responsive to said optical output signal from said second fiber for developing an electrical signal that has a DC component signal which has an amplitude proportional to the mean of said optical output signal and an AC component signal which has a peak-to-peak amplitude proportional to any information signal that may be present; and control means responsive to said DC component signal for controllably developing said first and second control signals to force said polarization controller to change the polarization state of said carrier light beam so that said carrier light beam at the input of said integrated optic device is maintained in a preselected polarization state in order to maintain the modulation efficiency of said integrated optic device at its optimum level.
Claim 7
Dependent Claim
16 words
The apparatus of claim 4 wherein: said integrated optic device comprises an integrated optic Mach-Zehnder modulator.
Claim 8
Dependent Claim
17 words
The apparatus of claim 4 wherein: said integrated optic device comprises an integrated optic directional coupler modulator.
Claim 9
Dependent Claim
41 words
The apparatus of claim 4 wherein said control means includes: a mean power detector responsive to said DC component signal for developing an error signal; and processing means responsive to said error signal for developing said first and second control signals.
Claim 10
Dependent Claim
48 words
The apparatus of claim 7 wherein said processing means includes: first and second means for respectively detecting first and second modulation components in said error signal; and first and second conditioning means for respectively changing said first and second modulation components to said first and second control signals.
Claim 11
Dependent Claim
25 words
The apparatus of claim 7 wherein said processing means includes: a microprocessor responsive to said error signal for developing said first and second control signals.
Claim 12
Dependent Claim
12 words
The apparatus of claim 4 wherein: said optical source is a laser.
Claim 13
Dependent Claim
14 words
The apparatus of claim 4 wherein: said second fiber is a second non-polarization-preserving fiber.
Claim 14
Independent Claim
210 words
A method for optimizing the modulation efficiency of a remotely-located, polarization-sensitive, integrated optic modulator which is addressed with a non-polarization-preserving fiber, said method comprising the steps of: utilizing a polarization controller to change the polarization state of an input light beam as a function of first and second control signals; propagating the input light beam with the changed polarization state through the non-polarization-preserving fiber to the input of an integrated optic modulator; developing an optical output signal in response to any information signal that may be present and to the input light beam with the changed polarization state; detecting the optical output signal to develop an electrical signal that has a DC component signal which has an amplitude proportional to the mean of the optical output signal and an AC component signal which has a peak-to-peak amplitude proportional to any information signal that may be present; and using the DC component signal to controllably develop first and second control signals which force the polarization controller to change the polarization state of the input light beam so that the input light beam at the input of the integrated optic modulator is maintained in a preselected polarization state to maintain the modulation efficiency of the integrated optic modulator at its optimum level.
Claim 15
Independent Claim
210 words
A method for optimizing the modulation efficiency of a remotely-located, polarization-sensitive, integrated optic modulator which is addressed with a non-polarization-preserving fiber, said method comprising the steps of: utilizing a polarization controller to change the polarization state of an input light beam as a function of first and second control signals; propagating the input light beam with the changed polarization state through the non-polarization-preserving fiber to the input of an integrated optic modulator; developing an optical output signal in response to any information signal that may be present and to the input light beam with the changed polarization state; detecting the optical output signal to develop an electrical signal that has a DC component signal which has an amplitude proportional to the mean of the optical output signal and an AC component signal which has a peak-to-peak amplitude proportional to any information signal that may be present; and using the DC component signal to controllably develop first and second control signals which force the polarization controller to change the polarization state of the input light beam so that the input light beam at the input of the integrated optic modulator is maintained in a preselected polarization state to maintain the modulation efficiency of the integrated optic modulator at its optimum level.
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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) | 1993-11-05 | 1994-05-07 | 1994-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-05 | 1998-05-07 | 1998-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-05 | 2002-05-07 | 2002-11-06 | $7700.00 | Window Closed / Lapsed |