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EP0078140A2
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Splice-free fiber optic recirculating memory
Assignee: Leland Stanford Junior University
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Filing: 1982-10-19
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Granted: —
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Expires: 2002-10-19
Abstract
Abstract A fiber optic recirculating memory is disclosed which utilizes a single splice-free single mode optical fiber (12) coupled to itself to form a loop (140) which acts as a delay line. A single signal supplied as an input to the optical fiber (12) will result in a series of output signals of identical form to the input signal, although at smaller, decreasing amplitudes. In addition to being useful as a recirculating memory device for use in a system where data is generated at a rate faster than it can be accepted by a data processor (154), the invention may be used as a tap filter (171) to pass a selected fundamental frequency and its harmonics, and to attenuate all other frequencies.
Inventors
- 👤 Herbert John Shaw
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 18:18
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/30; G11C21/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
152 words
A fiber optic recirculating memory device characterized by: an optical fiber (12) having an input end (142) for receiving optical signals and an output end (144) for emitting optical signals transmitted by the optical fiber (12); A loop (140) formed in the optical fiber ' (12) between the input end (142) and the output end (144); and an optical coupling device (10) connected between the input end (142) and the output end (144) of the optical fiber (12) for coupling a first percentage of the optical signal received at the input end (142) to the output end (144), and for introducing -a second percentage of the optical signals received at the input end (142) into the loop (140) for recirculation within the loop (140) and for coupling a percentage of the optical signal in the loop (140) to the output end (142) each time the optical signal recirculates through the loop (140).
Claim 2
Dependent Claim
152 words
A fiber optic recirculating memory device characterized by: an optical fiber (12) having an input end (142) for receiving optical signals and an output end (144) for emitting optical signals transmitted by the optical fiber (12); A loop (140) formed in the optical fiber ' (12) between the input end (142) and the output end (144); and an optical coupling device (10) connected between the input end (142) and the output end (144) of the optical fiber (12) for coupling a first percentage of the optical signal received at the input end (142) to the output end (144), and for introducing -a second percentage of the optical signals received at the input end (142) into the loop (140) for recirculation within the loop (140) and for coupling a percentage of the optical signal in the loop (140) to the output end (142) each time the optical signal recirculates through the loop (140).
Claim 3
Dependent Claim
100 words
A fiber optic recirculating memory device according to Claim 1 wherein the optical fiber (12) includes a central core (11) and an outer cladding (15) and the optical coupling device (10) includes apparatus (13a, 13b, 16a, 16b) for holding portions (18a, 18b) of the input end (142) and the output end (144) from which a portion of the cladding (15) has been removed in close facing relationship to form an interaction region (32) in which evanescent field coupling between the portions (18a, 18b) transfers light between the input end (142) and the output end (144) of the optical fiber (12).
Claim 4
Dependent Claim
22 words
A fiber optic recirculating memory device according to Claim- 1 or 2 wherein the optical fiber (12) is a single mode fiber.
Claim 5
Dependent Claim
24 words
A fiber optic recirculating memory device according to any preceding claim wherein the optical coupling device (10) has a coupling efficiency greater than 50%.
Claim 6
Dependent Claim
26 words
A fiber optic recirculating memory device according to any preceding claim wherein the loop (140) provides a predetermined delay time for transmission of optical signals therethrough.
Claim 7
Dependent Claim
36 words
A fiber optic recirculating memory device according to Claim 5 wherein the delay time is at least as long as the period of a signal of predetermined frequency to be stored in the recirculating memory device.
Claim 8
Dependent Claim
101 words
A fiber optic recirculating memory device according to any preceding claim wherein the optical coupling device (10) supplies a sequence of light pulses of identical shape to the output end (144) with the number of light pulses of useable level being determined by the formula where n is the number of useable output pulses, P t /P o is the ratio of minimum detectable power to the power of optical signals supplied to the input end (142), L is the coefficient of coupling of the optical coupling device (10), and K is the percentage of power transmitted by the loop (140).
Claim 9
Independent Claim
99 words
A method of producing a sequence of optical pulses from a single input pulse, each of the series of optical pulses being identical in shape to the input pulse, characterized by: forming a loop (140) in an optical fiber (12) having an input end (142) and an output end (144); supplying an input light pulse to the input end (142); coupling a percentage of the input light pulse into the loop (140) for recirculation therethrough; and coupling a percentage of the light in the loop to the output end (144) each time the pulse in the loop recirculates therethrough.
Claim 10
Independent Claim
99 words
A method of producing a sequence of optical pulses from a single input pulse, each of the series of optical pulses being identical in shape to the input pulse, characterized by: forming a loop (140) in an optical fiber (12) having an input end (142) and an output end (144); supplying an input light pulse to the input end (142); coupling a percentage of the input light pulse into the loop (140) for recirculation therethrough; and coupling a percentage of the light in the loop to the output end (144) each time the pulse in the loop recirculates therethrough.
References Cited (Backward Citations)
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