Dual coupler fiber optic recirculating memory

US4479701A · kind A · utility

Assignee

• The Board of Trustees of the Leland Stanford Junior University · US

Inventors

• Steven A. Newton · Belmont, US
• John E. Bowers · Holmdel, US
• Herbert J. Shaw · Stanford, US

Key dates

• Filing date: Dec 1, 1981
• Grant date: Oct 30, 1984
• Expiry date: Dec 1, 2001

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B6/29332
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A fiber optic recirculating memory is disclosed which utilizes dual couplers to form a splice-free recirculating memory device from a length of single mode optical fiber forming a loop which acts as a delay line and a second length of single mode optical fiber which provides an input end and an output end for the device. A single signal supplied as an input to the device will result in a series of output signals identical to the input signal, although at smaller, decreasing amplitudes; the invention prevents the first output signal from being substantially larger than the rest of the output signals, thus eliminating the need for protective circuitry on the output end or the rejection of the first output signal. 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, the invention may be used as a tap filter to pass a selected fundamental frequency and its harmonics, and to attenuate all other frequencies.