Abstract: A method of controlling at least one device is disclosed. The method includes providing the device with at least one constraint for carrying out an operation. The device determines if the constraint can be met. If it is determined that the constraint can be met, the device determines on its own accord a manner to get into a state wherein the constraint will be met. The device then goes into the state in the determined manner. A device that is controlled by the method and a system including such a device are also disclosed.

Abstract: An optical detection system includes a planar waveguide optical coupler that is directly adjacent to a polarizing beam splitter. The planar waveguide optical coupler combines an input signal with a local oscillator signal and the polarizing beam splitter divides the combined optical signal into orthogonally polarized beams. The orthogonally polarized beams are detected by first and second optical detectors. In one embodiment, the planar waveguide optical coupler is in contact with the polarizing beam splitter, in another embodiment, the planar waveguide optical coupler is attached to the polarizing beam splitter, and in another embodiment, the planar waveguide optical coupler and the polarizing beam splitter are attached to opposite sides of a polarization rotator.

Abstract: An optical switch includes a pump source, a pump director, and a pump-dependent attenuator. The pump-dependent attenuator passes optical signals when it is supplied with pump energy at a pumping wavelength and attenuates optical signals when it is not supplied with pump energy. The pump source generates pump energy for the pump-dependent attenuator, and the pump director optically manipulates the delivery of pump energy to the pump-dependent attenuator. In a preferred embodiment, the pump-dependent attenuator is an erbium-doped fiber (EDF), the pump source is a laser diode, and the pump director is a tunable fiber Bragg grating (FBG). The EDF is located along an optical signal transmission path between an input waveguide and an output waveguide. The tunable FBG is located along a transmission path between the laser diode and the EDF. To operate the switch, pump energy at a pumping wavelength is generated by the laser diode and transmitted toward the tunable FBG.

Abstract: An apparatus and method for measuring the thickness of a film having top and bottom surfaces. The apparatus includes a first coupler for generating a first probe light signal and a second probe light signal from a low coherence light source. The first probe light signal is directed toward the top surface of the film and the light leaving the top surface of the film is collected. Similarly, the second probe light signal is directed toward the bottom surface of the film and the light leaving the bottom surface of the film is also collected. Top and bottom partially reflecting reference surfaces are provided for generating reflections. The top reference surface reflects part of the light leaving the top surface back toward the top surface, and the bottom reference surface reflects light leaving the bottom surface of the film back toward the bottom surface of the film.

Abstract: An optical time domain reflectometer that injects at least two complementary code sequences into an optical fiber and detects the return signal produced by each of these code sequences. These return signals are processed to extract the function h.sub.k that is equal to the response function for the fiber when a single pulse is injected into the fiber. This processing utilizes a correlation scheme that has no sidelobe distortion. Various combinations of Golay codes are suitable for use as the complementary codes.

Abstract: A method of dynamically changing the measurement window and operating parameters of the instrument, based on intermediate results, in order to minimize the total time required to make a complete measurement. Also, a method of combining partial results from subwindows into a final result to be displayed that has not been corrupted by variation in system response due to time-varying operating parameters.

Abstract: A continuously variable optical delay line having a first substrate (66, 70) and a second substrate (95). The first substrate is composed of a quartz block (70) with a large radius of curvature along its length, supporting a silicon substrate (66) having a plurality of longitudinal, parallel v-grooves (68). A single length (121) of single mode optical fiber is wrapped around the first substrate (66, 70) in helical fashion with each loop being secured in one of the v-grooves (68). The portions of the fiber (121) in the v-grooves (68) are lapped and polished to create a flat coupling surface extending laterally and longitudinally across the first substrate (66, 70). The second substrate (91) is composed of a quartz block with a single v-groove holding a segment of single mode fiber (95). The radius of curvature of this v-groove is substantially smaller than that of the first substrate, such that the flat coupling surface of the second substrate (91) is shorter than that of the first substrate (66).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

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.