Patent US5315426A successfully refreshed from Google Patents.
US5315426A
Expired / Lapsed
US
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Optical transmitter
Assignee: NEC Corp
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Filing: 1992-03-16
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Granted: 1994-05-24
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Expires: 2012-03-16
Abstract
Abstract An optical transmitter includes a semiconductor laser which is supplied with a frequency modulated current. An emitted light from the semiconductor laser is modulated in intensity by an intensity modulator in accordance with an information signal and becomes a signal light pulse. The spectral width Δν m of the light and a power P s of the signal light pulse meet the following formulas: ##EQU1## where P th is a threshold input light power when the stimulated Brillouin scattering begins to occur in the optical fiber in case of no frequency modulation of said light, Δν B is the Brillouin gain bandwidth of the optical fiber, and Δν s is the spectral width of the signal light in case of no frequency modulation of the light.
Inventors
- 👤 Yasubiro Aoki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:55
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507; H04B10/2537
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
138 words
An optical transmitter, comprising: means for emitting a light: means for supplying a current modulated in frequency to said emitting means to be thereby driven; means for modulating said light in intensity in accordance with an information signal to generate a signal light pulse; and means for supplying said signal light pulse to an optical fiber; wherein a spectral width Δν m and a power P s of said signal light pulse meet the following formulas: ##EQU6## where P th is a threshold input light power when the stimulated Brillouin scattering begins to occur in said optical fiber in case of no frequency modulation of said light, Δν B is the Brillouin gain bandwidth of said optical fiber, and Δν s is the spectral width of said signal light in case of no frequency modulation of said light.
Claim 2
Dependent Claim
138 words
An optical transmitter, comprising: means for emitting a light: means for supplying a current modulated in frequency to said emitting means to be thereby driven; means for modulating said light in intensity in accordance with an information signal to generate a signal light pulse; and means for supplying said signal light pulse to an optical fiber; wherein a spectral width Δν m and a power P s of said signal light pulse meet the following formulas: ##EQU6## where P th is a threshold input light power when the stimulated Brillouin scattering begins to occur in said optical fiber in case of no frequency modulation of said light, Δν B is the Brillouin gain bandwidth of said optical fiber, and Δν s is the spectral width of said signal light in case of no frequency modulation of said light.
Claim 3
Dependent Claim
84 words
An optical transmitter, according to claim 1, wherein: said emitting means is a semiconductor laser; and said current supplying means comprises a direct current source which generates a direct current, an oscillator which generates an oscillated signal, and a mixer which mixes said oscillated signal with said direct current to generate a frequency modulated current to be supplied to said emitting means; wherein said emitting means supplies said light which is modulated in frequency in accordance with said mixed current supplied from said mixer.
Claim 4
Dependent Claim
78 words
An optical transmitter, according to claim 1, further comprising: means for splitting some part of said signal light pulse from said optical fiber; means for detecting said some part of said signal light to generate a detecting signal; and means for controlling said oscillated light supplied from said oscillator in accordance with said detecting signal so that the degree of said frequency modulation of said light is minimum so far as said stimulated Brillouin scattering does not occur.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1997-05-23 | 1997-11-22 | 1998-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-23 | 2001-11-22 | 2002-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-23 | 2005-11-22 | 2006-05-24 | $7700.00 | Window Closed / Lapsed |