Leland Stanford Junior University

Steven A Newton

Herbert J Shaw

John E Bowers

Cassius C Cutler

Kenneth P Jackson

Continuously variable fiber optic delay line

There is disclosed a high speed pulse train generator for generating a train of pulses having arbitrarily close spacing. The apparatus consists of a generator loop comprised of a fiber optic waveguide looped through a directional coupler with the output fiber serving as the input fiber for a similarly structured multiplexer loop. The lengths of the two loops are adjusted such that the time difference in the propagation times of light around the respective loops is small compared to the time of propagation around either loop. The times are adjusted to obtain any arbitrary spacing of the pulses in the output pulse train which is comprised of interleaved pulse trains resulting from each pulse input to the multiplexer loop. Also disclosed is a single loop embodiment for bidirectional data rate transformation and methods of using all the embodiments.

High speed pulse train generator

Method and apparatus for improving the sensitivity of Sagnac gyroscopes and other interferometers utilizing a fiber optic loop by minimizing the effects of backscattered radiation. In one disclosed embodiment, the amplitude of coincident backscattered radiation is significantly reduced by applying the light in the form of a pulse of short duration and gating the output so that only the scattered energy from a short length of the fiber contributes to the interfering wave. The interference is reduced even further by processing or constructing the loop to eliminate the scattering sources in the short segment which can give rise to coincident backscattered power.

Fiber optic loop interferometer and method with coincident backscatter

A fiber optic tapped delay line is disclosed which has a number of taps simultaneously fabricated in a single length of optical fiber. The light output from each tap is detected by either an electronic photodetector or by an output segment of optical fiber having a lapped surface, the latter technique also being utilizable in the mass production of optical couplers. The device may be used as a transversal filter by summing the outputs from the taps, and the frequency passband may be custom-tailored by selectively weighting the outputs from individual taps.

Tapped optical fiber delay line

A fiber optic tapped delay line is disclosed in which a number of bends in a single optical fiber are formed to obtain taps of an optical signal traveling in that fiber at each bend location. Light removed at the bends is directed to a focusing lens, which focuses the light onto a photodetector acting as a summing device to produce a frequency-filtered output of the light signal traveling in the fiber. The device's response as a transversal filter is enhanced by weighting the taps either by use of a cylindrical lens, or by selectively masking a portion of light emitted by selected individual taps.

Microbend optical fiber tapped delay line

A fiber optic data distributor utilizes a one-by-n single mode optical fiber directional coupler to distribute data from a single fiber to a plurality of separate fibers. The separate fibers may supply data from a central processing unit to peripheral units, which may also input data to the separate fibers for transmission to the central processing unit.

Fiber optic data distributor

A digital word generator uses a tap fiber optic delay line to generate a sequence of pulses. The pulses are weighted and combined to produce a digital word.

Fiber optic word generator

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.

Growing community of inventors

Menlo Park, CA, United States of America

Steven A Newton