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US3838278A
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Optical switching network utilizing organ arrays of optical fibers
Assignee: AT&T Inc
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Filing: 1973-09-28
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Granted: 1974-09-24
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Expires: 1993-09-28
Abstract
Abstract In a hybrid opto-electronic switching system, electronic information pulses appearing on an input signal path are used to drive a laser which generates corresponding optical information pulses. Each of the optical information pulses is divided into a plurality n of optical sub-pulses each of which is coupled through lens means to separate ones of a plurality n of optical fibers in an organ array; i.e., an array of optical fibers in parallel with one another and cut to different lengths. Gating means, normally in an off-state, is interposed between the outputs of the fibers and n output electronic signal paths (e.g., subscriber lines). Because the fibers of the organ array introduce different transit time delays, the plurality of optical sub-pulses arrive at the gating means at different times. A control unit is utilized to connect the m th output signal path to the input signal path by driving the gating means into an onstate at a time when the optical sub-pulse on the m th fiber reaches the gating means. Also described are systems for connecting any one of m input signal paths to any one of n output signal paths. These systems can also be used in optical communications systems as well as in electronic systems.
Inventors
- 👤 M Duguay
- 👤 J Galt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:06
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/42; H04Q3/52; H04Q3/526; H04J; H04J14/00; H04J14/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
221 words
An optical switch for connecting an input signal path carrying information in the form of pulses to a predetermined one of a plurality n of output signal paths, comprising: generating means for producing from each of said pulses a plurality of optical sub-pulses propagating along spatially separate optical paths, a first array of n optical fibers each having a different length and the difference in length between functionally adjacent fibers being uniform, one end of each of said fibers being terminated in an input plane and the opposite end of each of said fibers being terminated in an output plane, means for coupling each of said optical subpulses into a separate one of said fibers at said input plane, each of said optical sub-pulses thereby experiencing a different time delay in propagating from said input plane to said output plane, gating means disposed between the output plane of said first array and said output signal paths, said gating means being normally in an off-state which prevents transmission from said input signal path to said output signal paths, and timing means for causing said gating means to switch to an onstate when a predetermined one of said delayed optical subpulses reaches said gating means, thereby to permit said predetermined sub-pulse to be transmitted to a predetermined one of said output signal paths.
Claim 2
Dependent Claim
221 words
An optical switch for connecting an input signal path carrying information in the form of pulses to a predetermined one of a plurality n of output signal paths, comprising: generating means for producing from each of said pulses a plurality of optical sub-pulses propagating along spatially separate optical paths, a first array of n optical fibers each having a different length and the difference in length between functionally adjacent fibers being uniform, one end of each of said fibers being terminated in an input plane and the opposite end of each of said fibers being terminated in an output plane, means for coupling each of said optical subpulses into a separate one of said fibers at said input plane, each of said optical sub-pulses thereby experiencing a different time delay in propagating from said input plane to said output plane, gating means disposed between the output plane of said first array and said output signal paths, said gating means being normally in an off-state which prevents transmission from said input signal path to said output signal paths, and timing means for causing said gating means to switch to an onstate when a predetermined one of said delayed optical subpulses reaches said gating means, thereby to permit said predetermined sub-pulse to be transmitted to a predetermined one of said output signal paths.
Claim 3
Dependent Claim
44 words
The switch of claim 1 including delay compensation means disposed between said output plane of said first array and said output paths for making the total time delay for each path between said input path and said output paths nearly equal to one another.
Claim 4
Dependent Claim
67 words
The switch of claim 2 wherein said delay compensation means comprises a second array of n optical fibers each having a different length and the difference in length between functionally adjacent fibers being uniform, the fibers of said second array being optically coupled to the fibers of said first array at said output plane so that said total time delays are made nearly equal to one another.
Claim 5
Dependent Claim
76 words
The switch of claim 1 wherein: said generating means comprises a plurality of beam splitters arranged in tandem in the path of said pulses and oriented to produce said plurality of optical sub-pulses along said spatially separate optical paths, and said coupling means includes lens means having a characteristic focal length, said coupling means being positioned to receive said plurality of sub-pulses and to focus each of said sub-pulses into a separate one of said fibers.
Claim 6
Dependent Claim
34 words
The switch of claim 1 wherein: said input signal path carries digital information and said output signal paths carry analog information, and said gating means includes digital-to-analog converter means responsive to said timing means.
Claim 7
Dependent Claim
35 words
The switch of claim 1 wherein: said gating means includes photodetector means responsive to said timing means for converting said optical sub-pulses received from said first array to electrical pulses on a preselected output path.
Claim 8
Dependent Claim
73 words
The switch of claim 6 wherein said timing means includes: a differential discriminator having an electrical output connected to said gating means and two electrical inputs, a variable voltage bias source connected to one of said inputs for establishing predetermined threshold levels in said discriminator, and a ramp generator responsive to said pulses on said input signal path for generating a ramp voltage which is coupled to the other input of said discriminator.
Claim 9
Dependent Claim
56 words
The switch of claim 1 wherein: said gating means includes optical gate means responsive to said timing means for transmitting selected ones Of said delayed optical sub-pulses received from said first array, and said switch also includes photodetector means for converting said selected ones of said optical sub-pulseS to electrical pulses on a preselected output path.
Claim 10
Dependent Claim
73 words
The switch of claim 8 wherein said timing means includes: a differential discriminator having an electrical output connected to said gating means and two electrical inputs, a variable voltage bias source connected to one of said inputs for establishing predetermined threshold levels in said discriminator, and a ramp generator responsive to said pulses on said input signal path for generating a ramp voltage which is coupled to the other input of said discriminator.
Claim 11
Dependent Claim
58 words
The switch of claim 4 wherein said information pulses on said input signal path are electrical pulses which carry information in PCM form, in combination with: a discriminator-amplifier for regenerating said electrical pulses, said generating means includes a laser for producing optical pulses in response to said regenerated pulses, said optical pulses being coupled to said beam splitters.
Claim 12
Dependent Claim
124 words
An optical switching system for switching a pulsed input signal appearing on any one of m input signal paths to any one of n output signal paths comprising: a plurality m of optical switches of the type defined by claim 1 connected to separate ones of said m input signal paths, in each first array of each of said switches the kth fiber being coupled to the kth output signal path, 1 < or = k < or = n, and a central processing unit responsive to an input pulse on any one of said m input paths for controlling said timing means so that no more than one input signal path is connected to a particular output signal path at the same time.
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) | 1977-09-23 | 1978-03-25 | 1978-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-23 | 1982-03-25 | 1982-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-23 | 1986-03-25 | 1986-09-24 | $7700.00 | Window Closed / Lapsed |