US5446574A
Expired / Lapsed
US
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System and method for dispersion compensation in fibre optic high speed systems
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1994-03-25
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Granted: 1995-08-29
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Expires: 2014-03-25
Abstract
Abstract A system and a method for dispersion compensation in fiber optic high speed systems, the dispersion compensation being carried out in the transmitter. The system comprises a modulating device for modulating an information-carrying electric signal, an equalizing device for equalizing the signal modulated in the modulation device, and an electro-optic translating device for translating the signal equalized in the equalizing device into an optical signal substantially without loss of information and with substantially maintained phase and amplitude properties.
Inventors
- 👤 Anders G. Djupsjobacka
- 👤 Lars Egnell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:58
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507; H04B10/2513; H04B10/25133
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
87 words
System for dispersion compensation in a transmitter in a fiber optic high speed communication system comprising: means for modulating an electric carrier signal with an information-carrying electric signal and for generating a modulated signal; means for equalizing the modulated signal generated by the modulating means and for generating an equalized signal; and electro-optic means for translating, substantially without loss of information and with substantially maintained phase and amplitude properties, the equalized signal generated by the equalizing means to an optical signal for transmission through an optical fiber.
Claim 2
Dependent Claim
87 words
System for dispersion compensation in a transmitter in a fiber optic high speed communication system comprising: means for modulating an electric carrier signal with an information-carrying electric signal and for generating a modulated signal; means for equalizing the modulated signal generated by the modulating means and for generating an equalized signal; and electro-optic means for translating, substantially without loss of information and with substantially maintained phase and amplitude properties, the equalized signal generated by the equalizing means to an optical signal for transmission through an optical fiber.
Claim 3
Dependent Claim
18 words
The system of claim 1, wherein the modulating means generates a modulated signal having a predetermined intermediate frequency.
Claim 4
Dependent Claim
13 words
The system of claim 2, wherein the modulating means is an electric modulator.
Claim 5
Dependent Claim
13 words
The system of claim 3, wherein the equalizing device comprises an allpass filter.
Claim 6
Dependent Claim
35 words
The system of claim 2, wherein, for an information bandwidth corresponding to the information-carrying electric signal, the equalizing means has a dispersion having a sign that is opposite to respective dispersion in the optical fiber.
Claim 7
Dependent Claim
13 words
The system of claim 5, wherein the equalizing means comprises a transmission wire.
Claim 8
Dependent Claim
26 words
The system of claim 1, wherein the electro-optic translating means converts the equalized signal to an optical signal while maintaining the signal's phase and amplitude properties.
Claim 9
Dependent Claim
13 words
The system of claim 7, wherein the electro-optic translating means comprises a laser.
Claim 10
Dependent Claim
14 words
The system of claim 7, wherein the electro-optic translating means comprises an external modulator.
Claim 11
Dependent Claim
13 words
The system of claim 1, wherein the modulating means comprises an amplitude modulator.
Claim 12
Dependent Claim
29 words
The system of claim 10, wherein the electro-optic translating means comprises an electro-optic modulator for directly converting from an electric signal having an intermediate frequency to an optical signal.
Claim 13
Dependent Claim
14 words
The system of claim 11, wherein the electro-optic translating means comprises a laser diode.
Claim 14
Dependent Claim
54 words
The system of claim 11, wherein the electro-optic translating means includes an optical filter, and the optical signal is passed through the optical filter which has a narrow bandpass that transmits only a side band of the optical signal having a sign of dispersion that is opposite to the dispersion of the optical fiber.
Claim 15
Dependent Claim
66 words
The system of claim 13, wherein the optical filter lets through the side band of the optical signal having a sign of dispersion that is opposite to the dispersion of the optical fiber and a component of an optical carrier signal that has a state of polarization that is the same as a state of polarization of the optical signal for transmission through the optical fiber.
Claim 16
Dependent Claim
101 words
The system of claim 10, wherein the electro-optic translating means comprises a signal splitter, two mixers, two lowpass filters, two electro-optic modulators, and a laser diode; the splitter splits the equalized signal into two portions; the portions are passed through respective ones of the two mixers, which mix the portions with a cosine signal and a sine signal, respectively, thereby generating mixed signals having an intermediate frequency; the mixed signals are lowpass filtered by respective ones of the lowpass filters, thereby obtaining two baseband quadrature components; and the electro-optic modulators modulate light emitted by the laser diode with the quadrature components.
Claim 17
Dependent Claim
12 words
The system of claim 1, wherein the modulating means an argument modulator.
Claim 18
Dependent Claim
15 words
The system of claim 1, wherein the modulating means comprises an amplitude and argument modulator.
Claim 19
Dependent Claim
12 words
The system of claim 1, wherein the modulating means comprises a mixer.
Claim 20
Dependent Claim
13 words
The system of claim 1, wherein the modulating means comprises a frequency modulator.
Claim 21
Dependent Claim
31 words
The system of claim 19, wherein the electro-optic translating means comprises a frequency discriminator, and phase information in the modulated signal is converted into baseband amplitude information in the optical signal.
Claim 22
Dependent Claim
19 words
The system of claim 20, wherein the frequency discriminator comprises a delay line demodulator for phase or frequency demodulation.
Claim 23
Dependent Claim
38 words
The system of claim 21, wherein the modulated signal is a baseband amplitude signal, and the modulated signal is used to small-signal modulate a laser having linear amplitude-to-frequency-conversion characteristics, thereby obtaining an optical signal having maintained phase information.
Claim 24
Dependent Claim
13 words
The system of claim 1, wherein the modulating means comprises a phase modulator.
Claim 25
Dependent Claim
54 words
The system of claim 23, wherein the electro-optic translating means comprises a phase demodulator and an electro-optic phase modulator; phase information in the modulated signal is directly converted to an electrical baseband amplitude signal which, in the electro-optic phase modulator, is converted to a phase signal having maintained characteristics on an optical carder signal.
Claim 26
Independent Claim
72 words
A method for dispersion compensation in fiber optic high speed communication systems in which the dispersion compensation is carried out in a transmitter, comprising the steps of: modulating an electric carrier signal with an information-carrying electric signal and generating a modulated signal; equalizing the modulated signal and generating an equalized signal; and converting, in an electro-optic translating device, the equalized signal to an optical signal having essentially maintained phase and amplitude properties.
Claim 27
Independent Claim
72 words
A method for dispersion compensation in fiber optic high speed communication systems in which the dispersion compensation is carried out in a transmitter, comprising the steps of: modulating an electric carrier signal with an information-carrying electric signal and generating a modulated signal; equalizing the modulated signal and generating an equalized signal; and converting, in an electro-optic translating device, the equalized signal to an optical signal having essentially maintained phase and amplitude properties.
Claim 28
Dependent Claim
14 words
The method of claim 25, wherein the modulated signal has a predetermined intermediate frequency.
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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) | 1998-08-28 | 1999-02-27 | 1999-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-28 | 2003-02-27 | 2003-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-28 | 2007-02-27 | 2007-08-29 | $7700.00 | Window Closed / Lapsed |