Patent US6057919A successfully refreshed from Google Patents.
US6057919A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for measuring characteristics of optical pulses
Assignee: Japan Science and Technology Agency
•
Filing: 1997-07-11
•
Granted: 2000-05-02
•
Expires: 2017-07-11
Abstract
Abstract In an optical pulse characteristic measuring apparatus, optical pulses to be measured are introduced at the incident end, and split at an beam splitter. A first resultant light beam is reflected by a mirror as a local oscillation light of homodyne detection and is adjusted in a delay element so as to have the same optical path length as that of the second resultant light beam. Subsequently, the first light beam is led to an optical mixer. The second light beam is reflected by a mirror, which is controlled by a signal from a signal generator for modulation of optical path length difference. The second light beam is then reflected by a delay element and is led to the optical mixer. The two light beams combined at the optical mixer are detected by optical detectors. The AC signal component generated by modulation of the optical path length difference is amplified up to a measurable voltage by a differential amplifier. A bandpass filter passes only the AC signal component generated by modulation of the optical path length difference, thereby improving the S-N ratio. By using an AC voltmeter to measure the AC signal component corresponding to the delay of the delay element for correlation length measurement, the auto-correlation signal can be obtained. Accordingly, it is possible to measure the characteristics of optical pulses with high sensitivity and high stability.
Inventors
- 👤 Susumu Machida
- 👤 Shudong Jiang
- 👤 Yoshihisa Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:05
CPC Classifications
G; G04; G04F; G04F13/00; G04F13/02; G04F13/026; G01; G01J; G01J11/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
131 words
An apparatus for measuring characteristics of optical pulses comprising: (a) a beam splitter for splitting an input beam of optical pulses to be measured into a pair of light beams output therefrom; (b) means for modulating an optical path length of one of the pair of light beams output from said beam splitter; (c) means for changing the optical path length of one of said pair of light beams output from said beam splitter relative to the other of said pair of light beams output from said beam splitter; (d) an optical mixer for mixing the pair of output light beams; (e) an optical detector for detecting a light beam output from said optical mixer; and (f) means for measuring the amplitude of an AC signal output from said optical detector.
Claim 2
Independent Claim
131 words
An apparatus for measuring characteristics of optical pulses comprising: (a) a beam splitter for splitting an input beam of optical pulses to be measured into a pair of light beams output therefrom; (b) means for modulating an optical path length of one of the pair of light beams output from said beam splitter; (c) means for changing the optical path length of one of said pair of light beams output from said beam splitter relative to the other of said pair of light beams output from said beam splitter; (d) an optical mixer for mixing the pair of output light beams; (e) an optical detector for detecting a light beam output from said optical mixer; and (f) means for measuring the amplitude of an AC signal output from said optical detector.
Claim 3
Independent Claim
154 words
A method for measuring characteristics of optical pulses in an input light beam comprising the steps of: (a) splitting the input beam of optical pulses to be measured into first and second beams, b) modulating an optical path length of one of the first and second light beams, (c) changing an optical path length of one of the first and second light beams relative to the other of said first and second light beams, (d) mixing the first and second light beams, (e) detecting a light beam output from said optical mixer, and (f) measuring the amplitude of an AC signal output from said optical detector; wherein said modulating the optical path length of one of the first and second light beams and said detecting the light beam from the optical mixer performs heterodyne detection in order to measure the AC signal component which is generated by the modulation of the optical path length.
Claim 4
Independent Claim
154 words
A method for measuring characteristics of optical pulses in an input light beam comprising the steps of: (a) splitting the input beam of optical pulses to be measured into first and second beams, b) modulating an optical path length of one of the first and second light beams, (c) changing an optical path length of one of the first and second light beams relative to the other of said first and second light beams, (d) mixing the first and second light beams, (e) detecting a light beam output from said optical mixer, and (f) measuring the amplitude of an AC signal output from said optical detector; wherein said modulating the optical path length of one of the first and second light beams and said detecting the light beam from the optical mixer performs heterodyne detection in order to measure the AC signal component which is generated by the modulation of the optical path length.
Claim 5
Independent Claim
171 words
An apparatus for measuring characteristics of optical pulses comprising: (a) a beam splitter for splitting an input beam of optical pulses to be measured into a pair of light beams output therefrom; (b) means for modulating the optical path length of one of the pair of light beams output from said beam splitter; (c) means for changing the optical path length of one of said pair of light beams output from said beam splitter relative to the other of said pair of light beans output from said beam splitter; (d) means for chopping one of said pair of light beams output from said beam splitter; (e) an optical mixer for mixing the pair of output light beams; (f) an optical detector for detecting a light beam from said optical mixer; (g) detecting means for detecting the amplitude of an AC signal output from said optical detector; and (h) synchronous detecting means for detecting the amplitude of the output from said detecting means synchronously with the operation of said light chopping means.
Claim 6
Independent Claim
171 words
An apparatus for measuring characteristics of optical pulses comprising: (a) a beam splitter for splitting an input beam of optical pulses to be measured into a pair of light beams output therefrom; (b) means for modulating the optical path length of one of the pair of light beams output from said beam splitter; (c) means for changing the optical path length of one of said pair of light beams output from said beam splitter relative to the other of said pair of light beans output from said beam splitter; (d) means for chopping one of said pair of light beams output from said beam splitter; (e) an optical mixer for mixing the pair of output light beams; (f) an optical detector for detecting a light beam from said optical mixer; (g) detecting means for detecting the amplitude of an AC signal output from said optical detector; and (h) synchronous detecting means for detecting the amplitude of the output from said detecting means synchronously with the operation of said light chopping means.
Claim 7
Independent Claim
244 words
A method for measuring characteristics of optical pulses in an input light beam comprising the steps of: (a) splitting the input beam of optical pulses to be measured into first and second beams, (b) modulating an optical path length of one of the first and second light beams, (c) changing an optical path length of one of said first and second light beams relative to the other of said first and second light beams, (d) chopping one of the first and second light beams, (e) mixing the first and second light beams, (f) detecting a light beam generated by said mixing, (g) detecting the amplitude of an AC signal produced from the detecting of the light beam, and synchronously detecting the amplitude of an AC modulation component in the detected AC signal from the detecting of the light beam in synchronism with the chopping of one of the first and second light beams; wherein said modulating the optical path length of one off the first and second light beams, said chopping of one of said first and second light beams, said detecting of the amplitude of an AC signal produced from the detecting of the light beam and said synchronously detecting the amplitude of an AC modulation component in the detected AC signal from the detecting of the light beam performs heterodyne detection in order to detect and measure the AC modulation component which is generated by the modulation of the optical path length.
Claim 8
Independent Claim
244 words
A method for measuring characteristics of optical pulses in an input light beam comprising the steps of: (a) splitting the input beam of optical pulses to be measured into first and second beams, (b) modulating an optical path length of one of the first and second light beams, (c) changing an optical path length of one of said first and second light beams relative to the other of said first and second light beams, (d) chopping one of the first and second light beams, (e) mixing the first and second light beams, (f) detecting a light beam generated by said mixing, (g) detecting the amplitude of an AC signal produced from the detecting of the light beam, and synchronously detecting the amplitude of an AC modulation component in the detected AC signal from the detecting of the light beam in synchronism with the chopping of one of the first and second light beams; wherein said modulating the optical path length of one off the first and second light beams, said chopping of one of said first and second light beams, said detecting of the amplitude of an AC signal produced from the detecting of the light beam and said synchronously detecting the amplitude of an AC modulation component in the detected AC signal from the detecting of the light beam performs heterodyne detection in order to detect and measure the AC modulation component which is generated by the modulation of the optical path length.
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) | 2003-05-02 | 2003-11-01 | 2004-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-05-02 | 2007-11-01 | 2008-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-05-02 | 2011-11-01 | 2012-05-02 | $7700.00 | Window Closed / Lapsed |