Improved dither detection, measurement, and voltage bias adjustments for an electro-optical modulator are described. The electro-optical modulator generally includes RF electrodes and phase heaters interfaced with semi-conductor waveguides on the arms of Mach-Zehnder interferometers, where a processor is connected to output a bias tuning voltage to the electro-optical modulator for controlling optical modulation. A variable gain amplifier (VGA) can be configured with AC coupling connected to receive a signal from a transimpediance amplifier (TIA) that is configured to amply a photodetector signal from an optical tap that is used to measure an optical signal with a dither signal. The analog to digital converter (ADC) can be connected to receive output from the VGA. The processor can be connected to receive the signal from the ADC and to output the bias tuning voltage based on evaluation of the signal from the tap.

Aspects of the present disclosure describe large scale steerable optical switched arrays that may be fabricated on a common substrate including many thousands or more emitters that may be arranged in a curved pattern at the focal plane of a lens thereby allowing the directional control of emitted light and selective reception of reflected light suitable for use in imaging, ranging, and sensing applications including accident avoidance.

A device including a phosphor layer having a plurality of holes or pockets arranged within the phosphor layer to reduce lateral light transmission. The phosphor layer can be sized and positioned to extend over a plurality of LED emitter pixels.

An optical phase modulator includes a lower cladding layer, a core formed on the lower cladding layer, an upper cladding layer formed over the core, and a heater. In addition, the optical phase modulator includes a semiconductor layer which is embedded in the upper cladding layer, is disposed above the core, and is formed of a compound semiconductor, and the heater is constituted by an impurity introduction region formed in the semiconductor layer.

The present invention relates to optical power-limiting devices, and more particularly, to an optical power-limiting passive (self-adaptive) device and to a method for limiting solar power transmission in devices such as windows, using scattering level changes in a novel thermotropic composition that contains salt nano or microparticles embedded in a solid transparent host layer, where temperature change induces change in the refraction index of the matrix as well as of the embedded particles, creating a scattering layer, substantially reflecting the incident light thus limiting the amount of light passing through the window, green house covers, car sun roofs, solar panel windows and protection layers on housing roofs and walls, as a function of ambient temperature.

Switchable radiative energy harvesting systems and methods of harvesting radiation are disclosed. A system includes an optical filter that includes at least one of an active material and a passive material. The optical filter is switchable between a shield mode and a harvesting mode such that the at least one of the active material and the passive material is in a reflecting state during the shield mode such that the optical filter blocks passage of radiation from a thermal emitter to a thermophotovoltaic cell and a transmitting state during the harvesting mode such that that the optical filter allows the radiation to pass from the thermal emitter to the thermophotovoltaic cell.

Disclosed herein are systems and architecture for thermal waveguide-based phase shifters which improve thermal efficiency by having multi-pass waveguides arranged under the heating element in a serpentine fashion, with the waveguides having mismatched propagation constants. The combination allows for an increase in phase shift without increasing the length or the power consumption of the resistive heating element by increasing the total length of waveguide being heated by a singular heating element.

The present disclosure relates to a method including the following steps: a) forming a waveguide from a first material, the waveguide being configured to guide an optical signal; b) forming a layer made of a second material that is electrically conductive and transparent to a wavelength of the optical signal, steps a) and b) being implemented such that the layer made of the second material is in contact with at least one of the faces of the waveguide, or is separated from the at least one of the faces by a distance of less than half, preferably less than a quarter, of the wavelength of the optical signal. The application further relates to a phase modulator, in particular obtained by such a method.

Methods and apparatus are presented for measuring a photoluminescence (PL) response, preferably a spatially resolved image of a PL response, from an object exposed to solar irradiation. In certain embodiments signals from the object are measured in two or more different spectral bands selected such that one of the measured signals has a higher PL component relative to ambient reflectance compared to another measured signal, enabling the PL component to be enhanced by a suitable differencing procedure. In other embodiments a signal from an object is measured in a spectral band selected such that at least 20% of the measured signal comprises PL generated from the object by the solar irradiation. The methods and apparatus have particular application to outdoor inspection of photovoltaic modules without having to modulate the operating point of the modules.

A phase shifter includes a substrate layer, a cladding layer, and a waveguide. The phase shifter includes a waveguide and a heating element. The phase shifter includes a thermally conductive structure disposed on the cladding layer to disperse heat from the waveguide. The thermally conductive structure may include a metal strip disposed longitudinally along the beam, may include thermally conductive pads, and/or may include thermally conductive vias coupled between the cladding layer and the substrate layer. The phase shifter may be incorporated into light detection and ranging (LIDAR) devices, telecommunications devices, and/or computing devices.