The temperature sensitivity of a reflective electro-absorption modulator can be reduced through the use, e.g., in the optical cavity thereof, of optical materials having positive and negative thermo-optic coefficients (TOCs). In some embodiments, a multiple-quantum-well structure of the modulator comprises positive-TOC materials, and a Bragg reflector bounding the optical cavity comprises one or more negative-TOC materials. In some embodiments, the thicknesses of the layers of positive- and negative-TOC materials are selected such that the average refractive index along the optical path through the modulator is approximately temperature independent. In some embodiments, the optical length of the optical cavity is an integer multiple of a nominal operating wavelength.

Fiber optic terminals and fiber optic networks having variable ratio couplers are disclosed. The fiber optic terminals comprise a shell having a portion of a variable ratio coupler disposed therein. The variable ratio coupler comprises an optical input, a first optical output, a second optical output and a control. The control may be adjusted for changing an output power level between the first optical output and the second optical output.

A microwave photonic filter is provided. The filter includes an optical source, an electro-optic modulator, a single mode optical fiber, a few-mode optical fiber, and a photodiode. The electro-optic modulator is configured to receive an optical carrier from the optical source and an input electrical signal. The electro-optic modulator modulates the optical carrier based on the input electrical signal. The single mode optical fiber is configured to receive the modulated optical carrier from the electro-optic modulator. The few-mode optical fiber is configured to receive the modulated optical carrier from the single mode optical fiber. The filter includes one of a plurality of methods for causing higher order mode excitation in the few-mode fiber. The photodiode is configured to receive an output from the few-mode optical fiber.

A color-changing flexible fiber that can be incorporated into fabrics and other woven materials. The color changing flexible fibers are hollow and include at least two wire electrodes integrated into the wall of the hollow fiber that provide an electrical potential across an electro-optic medium disposed inside the hollow fiber. The electro-optic medium includes a non-polar solvent and at least one set of charged particles.

Disclosed herein are methods for forming an optical fiber preform using organic silica and germania precursors. The method includes depositing soot composed of germanium dioxide and silica on a substrate, removing the substrate, conducting a dehydration step and one or more heating steps under an oxygen-containing atmosphere to form the preform. Also disclosed are optical fibers drawn from the preforms produced herein.

An electro-optic beam controller, material processing apparatus, or optical amplifier, and corresponding methods, can include an actively controlled, waveguide-based, optical spatial mode conversion device. The conversion device can include a coupler, which can be a photonic lantern, configured to combine light beams into a common light beam; a sensor configured to measure at least one characteristic of the common light beam; and a controller configured to modulate optical parameters of the individual, respective light beams to set one or more spatial modes of the common light beam. Actively controlled and modulated devices can be used to maintain a stable, diffraction-limited beam for use in an amplification, communications, imaging, laser radar, switching, or laser material processing system. Embodiments can also be used to maintain a fundamental or other spatial mode in an optical fiber even while scaling to kilowatt power.

A method of processing by controlling one or more beam characteristics of an optical beam may include: launching the optical beam into a first length of fiber having a first refractive-index profile (RIP); coupling the optical beam from the first length of fiber into a second length of fiber having a second RIP and one or more confinement regions; modifying the one or more beam characteristics of the optical beam in the first length of fiber, in the second length of fiber, or in the first and second lengths of fiber; confining the modified one or more beam characteristics of the optical beam within the one or more confinement regions of the second length of fiber; and/or generating an output beam, having the modified one or more beam characteristics of the optical beam, from the second length of fiber. The first RIP may differ from the second RIP.

A display screen includes: a display panel with a display region and a non-display region, wherein the display region includes an intermediate display region and a peripheral display region surrounding the intermediate display region; an image expansion structure disposed in the peripheral display region, wherein the image expansion structure is configured to expand an image displayed by the peripheral display region of the display panel to the non-display region to cover the non-display region.

A fiber optic sensor arrangement is disclosed that includes a plurality of optical fiber based sensor elements, the sensor elements configured to modify an associated optical carrier signal in accordance with changes in a sensed quantity at a location of the sensor element and a phase modulation arrangement for phase modulating each optical carrier signal in accordance with respective uncorrelated pseudorandom binary sequence signals. The sensor arrangement also includes an interferometer module for receiving each of the phase modulated optical carrier signals, the interferometer module operable to convert a change in the phase modulated optical carrier signals to a change in optical intensity of the corresponding optical carrier signal to generate a combined modulated optical intensity signal, an optical intensity detector for measuring the combined modulated optical intensity signal and generating a time varying electrical detector signal and an analog to digital convertor to convert the time varying electrical detector signal to a time varying digitized detector signal. Also included in the sensor arrangement is a decorrelator arrangement for decorrelating the time varying digitized detector signal against the respective uncorrelated pseudorandom binary sequence corresponding to each of the optical carrier signals to recover each of the modulated optical carrier signals and a demodulator for demodulating each of the modulated optical carrier signals to recover the respective optical carrier signal to determine the changes in the sensed quantity at the location of the sensor element.

A system and methods for providing optical, downhole data communication without requiring a light source in the downhole tool is disclosed. A carrier signal generated at the surface is sent to the downhole tool using an optical fiber. An optical modulator of the downhole tool uses data signals from a sensor to modulate the carrier signal based on the data signals. The modulated signal is transmitted to one or more optical receivers. The optical modulator can be coupled to the one or more optical receivers through the same optical fiber as the carrier signal generator, or one or more additional optical fibers.