Integrated Visible-Light Liquid-Crystal Phase Modulator

Abstract

An integrated liquid-crystal phase modulator for applications within the visible wavelength range is demonstrated. A threshold voltage of ±1.2V is shown and 24π phase shift is achieved within ±2.5V in a 500-μm-long modulator.

Integrated optical phased arrays: augmented reality, LiDAR, and beyond

“…Finally, in Ch. 4, a novel transparent integrated-phased-array-based holographic display will be proposed as a highly-discreet and fully-holographic solution for the next generation of augmented-reality head-mounted displays; novel passive near-eye displays that generate holograms [18,19], the first integrated visible-light liquid-crystalbased phase [20,21] and amplitude [22,23] modulators, and the first actively-tunable visible-light integrated optical phased arrays [24] will be presented.…”

“…First, a variety of novel integrated visible-light components, required for the VIPER display, will be demonstrated. The first integrated visible-light liquid-crystalbased phase [20,21] and amplitude [22,23] modulators (with device lengths an order of magnitude smaller than traditional inefficient thermo-optic visible-light modula-Introduction…”

“…Second, a novel large-scale passive VIPER display that generates a holographic image of a wire-frame cube using 1024 optical-phased-array-based pixels passively encoded to emit light with the appropriate amplitudes and phases will be discussed. 16 Third, the first integrated visible-light liquid-crystal-based phase 17,18 and amplitude 19 modulators will be shown (with device lengths an order of magnitude smaller than traditional inefficient thermooptic visible-light modulators). Fourth, the first actively-tunable visible-light integrated optical phased array will be presented 20 (prior visible-light optical phased arrays have been limited to passive demonstrations).…”

“…Figure 4.19 shows a schematic of one of the pixels in the active VIPER display.Each pixel consists of (1) a liquid-crystal-based phase shifter[21] on the row waveguide to modulate the absolute phase of the light emitted by each pixel, (2) a liquid-crystalbased variable tap[23] to modulate the amplitude of light coupled from the row waveguide to each pixel bus, and (3) a liquid-crystal-based pixel bus with compact cascaded pixel-bus-to-antenna taps to distribute the light from the pixel bus to 8…”

Power-Efficient Silicon Nitride Thermo-Optic Phase Shifters for Visible Light

“…Phase shifters based on thermally-tuned SiN microdisks and microrings have P π of 0.68−2.1 mW at wavelengths of 488 and 530 nm [19][20][21]; however, the low power consumption is attained at the expense of increased wavelength and fabrication error sensitivity compared to non-resonant structures. SiN phase shifters with liquid crystal cladding are expected to have significantly lower power consumption and such devices have been demonstrated at a wavelength of λ = 630 nm [22,23], but post-processing steps are required to apply and encapsulate the liquid crystal. Low-loss lithium niobate nanophotonic waveguides have been demonstrated at red and near-infrared wavelengths (634 − 638 nm, 720 − 850 nm), and ultra-low power phase shifters have been demonstrated at a wavelength of 850 nm [24]; however, the incompatibility of lithium niobate processing with standard silicon photonics fabrication limits the levels of integration that may be achieved.…”