US4551684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noise reduction in laser amplifiers
Assignee: Newport Corp USA
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Filing: 1983-02-04
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Granted: 1985-11-05
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Expires: 2003-02-04
Abstract
Abstract Amplified spontaneous emission is substantially reduced in a novel optical amplifier wherein the gain medium is disposed within a converging region of the coherent signal, which converging region terminates in a waist at or near a limiting stop or saturable absorber. In contrast to the converging coherent signal flux, the amplified spontaneous emission flux is nonconverging and therefore most of the latter is removed by a spatial filter or saturable absorber.
Inventors
- 👤 Anthony F. Bernhardt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:57
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/23; H01S3/2308; H01S3/05; H01S3/08; H01S3/081; H01S3/083; H01S2301/00; H01S2301/02; H01S3/08018; H01S3/0804; H01S3/0805; H01S3/2325; H01S3/235
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
142 words
Amplification apparatus for unidirectional propagation of an optical signal along a propagation axis through a gain medium with suppression of concomitant amplified spontaneous emission, comprising (a) converging means for accepting said optical signal and forming a waist in the radial extent thereof at a point distant along the propagation axis of said optical signal, (b) optical isolator means for selective transmission of optical flux incident thereon, said optical isolator means disposed substantially at said waist, (c) optical gain medium means for increasing the optical intensity of said propagating optical signal through stimulated emission phenomena, said gain medium disposed intermediate said converging means and said isolator means, whereby spontaneous emission noise occuring in and amplified by said gain medium is spatially dispersed in relation to the converging optical signal, and (d) a diverging lens disposed between said gain medium and said pinhole aperture.
Claim 2
Dependent Claim
142 words
Amplification apparatus for unidirectional propagation of an optical signal along a propagation axis through a gain medium with suppression of concomitant amplified spontaneous emission, comprising (a) converging means for accepting said optical signal and forming a waist in the radial extent thereof at a point distant along the propagation axis of said optical signal, (b) optical isolator means for selective transmission of optical flux incident thereon, said optical isolator means disposed substantially at said waist, (c) optical gain medium means for increasing the optical intensity of said propagating optical signal through stimulated emission phenomena, said gain medium disposed intermediate said converging means and said isolator means, whereby spontaneous emission noise occuring in and amplified by said gain medium is spatially dispersed in relation to the converging optical signal, and (d) a diverging lens disposed between said gain medium and said pinhole aperture.
Claim 3
Dependent Claim
20 words
The amplifier apparatus of claim 1 further comprising a diverging lens disposed between said gain medium and said saturable absorber.
Claim 4
Independent Claim
127 words
The method of enhancing the signal to noise ratio at the output of an optical amplifier stage, comprising the steps of (a) introducing an optical signal to said amplifier stage, (b) converging said optical signal to form a waist in the transverse extent of said optical signal, (c) amplifying by stimulated emission phenomena said optical signal and concomitant spontaneous emission flux while carrying out said converging step, (d) selectively transmitting said converging amplified optical signal from said amplifier stage while selectively attenuating substantially all nonconverging flux issuing from said amplifier stage, and (e) diverging said converging amplified signal by an amount insufficient to substantially affect the intensity of said signal transmitting step thereof while diverging said nonconverging flux for attenuation of a still substantially greater portion thereof.
Claim 5
Independent Claim
127 words
The method of enhancing the signal to noise ratio at the output of an optical amplifier stage, comprising the steps of (a) introducing an optical signal to said amplifier stage, (b) converging said optical signal to form a waist in the transverse extent of said optical signal, (c) amplifying by stimulated emission phenomena said optical signal and concomitant spontaneous emission flux while carrying out said converging step, (d) selectively transmitting said converging amplified optical signal from said amplifier stage while selectively attenuating substantially all nonconverging flux issuing from said amplifier stage, and (e) diverging said converging amplified signal by an amount insufficient to substantially affect the intensity of said signal transmitting step thereof while diverging said nonconverging flux for attenuation of a still substantially greater portion thereof.
Claim 6
Dependent Claim
170 words
A traveling wave optical amplifier comprising (a) at least one gain stage comprising an input and output portion, (b) a feedback path for communication between said input and output portions, (c) a unidirectional transmission element disposed in said feedback path for selective attenuation of signal flux in said feedback path having a propogation direction other than from said output portion toward said input portion, (d) means for introducing a coherent signal to said input portion, (e) means for coupling a portion of the amplified signal from said traveling wave amplifier to form an output signal, said input portion comprising converging means for imposing convergence upon a portion of said coherent signal to form a waist in the spatial extent of said coherent signal followed by a diverging portion downstream of said waist, said gain stage further comprising a gain medium disposed within said converging portion of the coherent signal, a selective transmission element disposed substantially at said waist and means for collimating said the signal flux following said diverging portion.
Claim 7
Dependent Claim
170 words
A traveling wave optical amplifier comprising (a) at least one gain stage comprising an input and output portion, (b) a feedback path for communication between said input and output portions, (c) a unidirectional transmission element disposed in said feedback path for selective attenuation of signal flux in said feedback path having a propogation direction other than from said output portion toward said input portion, (d) means for introducing a coherent signal to said input portion, (e) means for coupling a portion of the amplified signal from said traveling wave amplifier to form an output signal, said input portion comprising converging means for imposing convergence upon a portion of said coherent signal to form a waist in the spatial extent of said coherent signal followed by a diverging portion downstream of said waist, said gain stage further comprising a gain medium disposed within said converging portion of the coherent signal, a selective transmission element disposed substantially at said waist and means for collimating said the signal flux following said diverging portion.
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) | 1988-11-04 | 1989-05-06 | 1989-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-04 | 1993-05-06 | 1993-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-04 | 1997-05-06 | 1997-11-05 | $7700.00 | Window Closed / Lapsed |