US5033114A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser calibration
Assignee: Massachusetts Institute of Technology
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Filing: 1989-08-28
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Granted: 1991-07-16
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Expires: 2009-08-28
Abstract
Abstract In the laser diode calibration scheme disclosed herein, a glow discharge device ie employed which has an optogalvanic response wavelength within the wavelength tuning range of the laser diode. By measuring the proportion of laser diode light output which passes through an interference filter having a known wavelength dependent response, an initial operating region is determined which is at least proximate the optogalvanic response wavelength. By varying the current through or temperature of the diode within the operating region while measuring the optogalvanic response, an operating point corresponding to the response wavelength is determined. While modulating the laser diode at the data rate and at different modulation amplitudes across a response peak provided by Fabry-Perot interferometer, the relative amplitudes of sidebands generated by the interferometer are measured and compared thereby to determine a modulation amplitude providing a deviation which is a predetermined multiple of the data rate.
Inventors
- 👤 Vijaysekher Jayaraman
- 👤 Emily S. Kintzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:50
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/50; H04B10/564; H04B10/501; H04B10/503; H04B10/504; H04B10/572
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
147 words
The method of calibrating a laser diode for FSK data communication at a given data rate which comprises providing a glow discharge device having an optogalvanic response wavelength within tuning range of said laser diode; varying the current through the diode while measuring the portion of the laser diode's light output which passes through a filter having a progressive response at the laser's output wavelength, thereby to determine an operating region which is at least proximate said optogalvanic response wavelength; varying the current through said diode within said operating region while measuring said optogalvanic response, thereby to determine an operating point corresponding to said response wavelength; modulating said laser diode at said data rate to scan a response peak provided by an interferometer while varying the modulation amplitude and measuring the relative amplitudes of side bands generated by an interferometer thereby to determine a desired modulation amplitude.
Claim 2
Independent Claim
147 words
The method of calibrating a laser diode for FSK data communication at a given data rate which comprises providing a glow discharge device having an optogalvanic response wavelength within tuning range of said laser diode; varying the current through the diode while measuring the portion of the laser diode's light output which passes through a filter having a progressive response at the laser's output wavelength, thereby to determine an operating region which is at least proximate said optogalvanic response wavelength; varying the current through said diode within said operating region while measuring said optogalvanic response, thereby to determine an operating point corresponding to said response wavelength; modulating said laser diode at said data rate to scan a response peak provided by an interferometer while varying the modulation amplitude and measuring the relative amplitudes of side bands generated by an interferometer thereby to determine a desired modulation amplitude.
Claim 3
Independent Claim
171 words
The method of calibrating a laser diode for FSK data communication at a given data rate which comprises providing a glow discharge device having an optogalvanic response wavelength within tuning range of said laser diode; varying the current through the diode while measuring the portion of the laser diode's light output which passes through an interference filter having a progressive response over the laser's nominal operating wavelength range, thereby to determine an operating region which includes said optogalvanic response wavelength; varying the current through said diode within said operating region while measuring said optogalvanic response, thereby to determine an operating point corresponding to said response wavelength; modulating said laser diode at said data rate and at different modulation amplitudes while scanning a response peak provided by an interferometer providing repetitive peaks in said operating region and measuring the relative amplitudes of side bands generated by an interferometer at different modulation amplitudes thereby to determine a desired modulation amplitude providing a modulation deviation which is a predetermined multiple of the data rate.
Claim 4
Independent Claim
171 words
The method of calibrating a laser diode for FSK data communication at a given data rate which comprises providing a glow discharge device having an optogalvanic response wavelength within tuning range of said laser diode; varying the current through the diode while measuring the portion of the laser diode's light output which passes through an interference filter having a progressive response over the laser's nominal operating wavelength range, thereby to determine an operating region which includes said optogalvanic response wavelength; varying the current through said diode within said operating region while measuring said optogalvanic response, thereby to determine an operating point corresponding to said response wavelength; modulating said laser diode at said data rate and at different modulation amplitudes while scanning a response peak provided by an interferometer providing repetitive peaks in said operating region and measuring the relative amplitudes of side bands generated by an interferometer at different modulation amplitudes thereby to determine a desired modulation amplitude providing a modulation deviation which is a predetermined multiple of the data rate.
Claim 5
Dependent Claim
17 words
The method as set forth in claim 2 wherein said discharge device is a neon glow lamp.
Claim 6
Dependent Claim
38 words
The method as set forth in claim 3 wherein said operating point is determined by modulating said laser around said optogalvanic response wavelength while measuring the a.c. component of the voltage across said lamp at the modulation frequency.
Claim 7
Dependent Claim
27 words
The method as set forth in claim 2 wherein said response peak is one of a succession of response peaks provided by a fixed confocal Fabry-Perot interferometer.
Claim 8
Independent Claim
119 words
The method of calibrating a laser diode for FSK data communication at a given data rate which comprises providing a glow discharge device having an optogalvanic response wavelength within tuning range of said laser diode; varying the current through said diode within said operating region while measuring said optogalvanic response, thereby to determine an operating point corresponding to said response wavelength; modulating said laser diode at said data rate and at different modulation amplitudes while scanning a response peak provided by an interferometer providing repetitive peaks in said operating region and measuring the relative amplitudes of side bands generated by an interferometer thereby to determine a desired modulation amplitude providing a modulation deviation which is twice the data rate.
Claim 9
Independent Claim
119 words
The method of calibrating a laser diode for FSK data communication at a given data rate which comprises providing a glow discharge device having an optogalvanic response wavelength within tuning range of said laser diode; varying the current through said diode within said operating region while measuring said optogalvanic response, thereby to determine an operating point corresponding to said response wavelength; modulating said laser diode at said data rate and at different modulation amplitudes while scanning a response peak provided by an interferometer providing repetitive peaks in said operating region and measuring the relative amplitudes of side bands generated by an interferometer thereby to determine a desired modulation amplitude providing a modulation deviation which is twice the data rate.
Claim 10
Dependent Claim
202 words
Apparatus for calibrating a laser diode for FSK data communications, said apparatus comprising: a filter having a known wavelength dependent response at the laser diode's nominal operating wavelength; means for directing a portion of the light emitted by said diode through said filter; detector means for measuring the proportion of light transmitted by said filter; a glow discharge device having an optogalvanic response wavelength within tuning range of said laser diode; means for directing a portion of the light emitted by said diode onto said glow discharge device; an interferometer providing a response exhibiting a peak within said range; means for directing a portion of the light emitted by said diode through said interferometer; and programmable means for controlling the energization of said laser diode while monitoring said detector means to determine an operating region for said laser diode which is at least proximate said optogalvanic response wavelength, for controlling the energization of said laser diode while monitoring said discharge device to determine an operating point for said laser diode which corresponds to said response wavelength, and for controlling the energization of said laser diode while monitoring the response of said interferometer thereby to determine the modulation sensitivity of said laser diode.
Claim 11
Dependent Claim
202 words
Apparatus for calibrating a laser diode for FSK data communications, said apparatus comprising: a filter having a known wavelength dependent response at the laser diode's nominal operating wavelength; means for directing a portion of the light emitted by said diode through said filter; detector means for measuring the proportion of light transmitted by said filter; a glow discharge device having an optogalvanic response wavelength within tuning range of said laser diode; means for directing a portion of the light emitted by said diode onto said glow discharge device; an interferometer providing a response exhibiting a peak within said range; means for directing a portion of the light emitted by said diode through said interferometer; and programmable means for controlling the energization of said laser diode while monitoring said detector means to determine an operating region for said laser diode which is at least proximate said optogalvanic response wavelength, for controlling the energization of said laser diode while monitoring said discharge device to determine an operating point for said laser diode which corresponds to said response wavelength, and for controlling the energization of said laser diode while monitoring the response of said interferometer thereby to determine the modulation sensitivity of said laser diode.
Claim 12
Dependent Claim
227 words
Apparatus for calibrating a laser diode for FSK data communications at a given data rate, said apparatus comprising: an interference filter having a known wavelength dependent at the laser diode's nominal operating wavelength; means for directing a portion of the light emitted by said diode through said filter; detector means for measuring the proportion of light transmitted by said filter; a glow discharge device having an optogalvanic response wavelength within the tuning range of said laser diode; means for directing a portion of the light emitted by said diode onto said glow discharge device; an interferometer providing a response exhibiting a series of peaks within said range; means for directing a portion of the light emitted by said diode through said interferometer; and programmable means for controlling the energization of said laser diode while monitoring said detector means to determine an operating region for said laser diode which includes said optogalvanic response wavelength, for controlling the energization of said laser diode while monitoring said discharge device to determine an operating point for said laser diode which corresponds to said response wavelength, and for modulating said laser diode at said data rate and at different modulation amplitudes while scanning a response peak provided by said interferometer and while monitoring the relative amplitudes of sidebands generated by said interferometer thereby to determine the modulation sensitivity of said laser diode.
Claim 13
Dependent Claim
227 words
Apparatus for calibrating a laser diode for FSK data communications at a given data rate, said apparatus comprising: an interference filter having a known wavelength dependent at the laser diode's nominal operating wavelength; means for directing a portion of the light emitted by said diode through said filter; detector means for measuring the proportion of light transmitted by said filter; a glow discharge device having an optogalvanic response wavelength within the tuning range of said laser diode; means for directing a portion of the light emitted by said diode onto said glow discharge device; an interferometer providing a response exhibiting a series of peaks within said range; means for directing a portion of the light emitted by said diode through said interferometer; and programmable means for controlling the energization of said laser diode while monitoring said detector means to determine an operating region for said laser diode which includes said optogalvanic response wavelength, for controlling the energization of said laser diode while monitoring said discharge device to determine an operating point for said laser diode which corresponds to said response wavelength, and for modulating said laser diode at said data rate and at different modulation amplitudes while scanning a response peak provided by said interferometer and while monitoring the relative amplitudes of sidebands generated by said interferometer thereby to determine the modulation sensitivity of said laser diode.
Claim 14
Dependent Claim
17 words
The method as set forth in claim 8 wherein said discharge device is a neon glow lamp.
Claim 15
Dependent Claim
38 words
The method as set forth in claim 9 wherein said operating point is determined by modulating said laser around said optogalvanic response wavelength while measuring the a.c. component of the voltage across said lamp at the modulation frequency.
Claim 16
Dependent Claim
27 words
The method as set forth in claim 8 wherein said response peak is one of a succession of response peaks provided by a fixed confocal Fabry-Perot interferometer.
Claim 17
Dependent Claim
155 words
Apparatus for calibrating a laser diode for FSK data communications at a given data rate, said apparatus comprising: a glow discharge device having an optogalvanic response wavelength within the tuning range of said laser diode; means for directing a portion of the light emitted by said diode onto said glow discharge device; an interferometer providing a response exhibiting a series of peaks within said range; means for directing a portion of the light emitted by said diode through said interferometer; programmable means controlling the energization of said laser diode while monitoring said discharge device to determine an operating point for said laser diode which corresponds to said response wavelength, and for modulating said laser diode at said data rate and at different modulation amplitudes while scanning a response peak provided by said interferometer and while monitoring the relative amplitudes of sidebands generated by said interferometer thereby to determine the modulation sensitivity of said laser diode.
Claim 18
Dependent Claim
155 words
Apparatus for calibrating a laser diode for FSK data communications at a given data rate, said apparatus comprising: a glow discharge device having an optogalvanic response wavelength within the tuning range of said laser diode; means for directing a portion of the light emitted by said diode onto said glow discharge device; an interferometer providing a response exhibiting a series of peaks within said range; means for directing a portion of the light emitted by said diode through said interferometer; programmable means controlling the energization of said laser diode while monitoring said discharge device to determine an operating point for said laser diode which corresponds to said response wavelength, and for modulating said laser diode at said data rate and at different modulation amplitudes while scanning a response peak provided by said interferometer and while monitoring the relative amplitudes of sidebands generated by said interferometer thereby to determine the modulation sensitivity of said laser diode.
References Cited (Backward Citations)
US4926429A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-07-15 | 1995-01-14 | 1995-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-15 | 1999-01-14 | 1999-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-15 | 2003-01-14 | 2003-07-16 | $7700.00 | Window Closed / Lapsed |