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.

A display device includes a directional illuminator providing a light beam, a display panel downstream of a directional illuminator, for receiving and spatially modulating the light beam, and a beam redirecting module downstream of the display panel, for variably redirecting the spatially modulated light beam. Steering the illuminating light by the beam redirecting module enables one to steer the exit pupil of the display device to match the user's eye location(s).

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.

An apparatus (10) for increasing a pulse length of a pulsed radiation beam, the apparatus comprising: a beam splitter (16) configured to split an input radiation beam (18) into a first beam (24) and a second beam (22); an optical arrangement (12, 14), wherein the beam splitter and the optical arrangement are configured such that at least a portion of the first beam is recombined with the second beam into a modified beam after an optical delay of the first beam caused by the optical arrangement; and at least one optical element (30) in an optical path of the first beam, the at least one optical element configured such that the phase of different parts of a wavefront of the first beam is varied to reduce coherence between the first beam and the second beam.

A diffraction-limited, programmable pulse shaping network using a virtually integrated phased array (VIPA)-grating pair, integrated with a 2-d transmissive phase-only spatial light modulator (SLM) and a retro-array phase-conjugate mirror (RA-PCM). A high-temporal resolution, broadband pulse shaping network is realized using a 2-D VIPA-grating dispersive element pair, with a programmable SLM at a common Fourier transform plane. True wavefront reversal (“time reversal”) is realized using a self-starting RA-PCM, which compensates for system path distortions, misalignment, beam wander, vibrations and optical aberrations. Upon reverse transit through the system, the RA-PCM wavefront matches the set of virtual images emerging from the VIPA. The RA-PCM is a self-starting, low-power device, without frequency shifts, doesn't require pump beams and/or the need for high-intensity stimulated scattering threshold conditions to be met. Polarization decoupling enables the RA-PCM to compensate for optical distortions, while enabling the SLM to generate real time Fourier phase masks for programmable pulse shaping.

Various embodiments of the present disclosure are directed towards an integrated chip including a waveguide and a heater structure. The waveguide is disposed on a substrate and comprises an active region that extends continuously along a first distance. The heater structure overlies the waveguide. The heater structure comprises a conductive structure over the active region and a vertical structure disposed between the conductive structure and the substrate. The vertical structure comprises a conductive upper vertical segment and a lower vertical segment. The conductive structure and the conductive upper vertical segment continuously laterally extend across a second distance that is greater than or equal to the first distance. The first distance is greater than a width of the conductive structure.

The disclosure provides a display device and a holographic display apparatus. The display device includes a display panel including a first linear polarizer located on a light-emitting side, so that the display panel emits linearly polarized image light; and a phase modulation panel disposed on the light-emitting side of the display panel and configured to perform phase modulation on the linearly polarized image light. The holographic display apparatus includes the display device.

Liquid crystal light beam control devices and their manufacture are described. Beneficial aspects of beam broadening devices employed for controlled illumination and architectural purposes are presented including improving beam divergence control, improving beam broadening dynamic range control, beam divergence preconditioning, improving projected beam intensity uniformity.

Structures including an electro-optical phase shifter and methods of fabricating a structure including an electro-optical phase shifter. The structure includes a waveguide core on a semiconductor substrate, and an interconnect structure over the waveguide core and the semiconductor substrate. The waveguide core includes a phase shifter, and the interconnect structure includes a slotted shield and a transmission line coupled to the phase shifter. The slotted shield includes segments that are separated by slots. The slotted shield is positioned between the transmission line and the substrate.

Architecture and designs of modulating both amplitude and phase at the same time in spatial light modulation are described. According to one aspect of the present invention, light propagation is controlled in two different directions (e.g., 0 and 45 degrees) to perform both amplitude modulation and phase modulation at the same time in liquid crystals. In one embodiment, a mask is used to form a pattern, where the pattern includes an array of alignment cells or embossed microstructures, a first group of the cells are aligned in the first direction and a second group of the cells are aligned in the second direction. Depending on applications, two cells from the first group and the second group may correspond to a single pixel or two neighboring pixels, resulting in amplitude modulation and phase modulation within the pixel or within an array of pixels.