An eyepiece includes a substrate and an in-coupling grating patterned on a single side of the substrate. A first grating coupler is patterned on the single side of the substrate and has a first grating pattern. The first grating coupler is optically coupled to the in-coupling grating. A second grating coupler is patterned on the single side of the substrate adjacent to the first grating coupler. The second grating coupler has a second grating pattern different from the first grating pattern. The second grating coupler is optically coupled to the in-coupling grating.

A device and methods, the device comprising: a photo detector comprising a waveguide; two metal layers connected to the photo detector; a measurement device connected between the two metal layers, for measuring an electric parameter between the two metal layers, said electric parameter indicative of an amount of light propagating through the waveguide; and a voltage source connected between the two metal layers, wherein applying voltage between the two metal layers changes a refraction index of the waveguide, thereby affecting a phase of light propagating through the waveguide, and wherein the voltage to be applied is determined in accordance with the resistance measured by the resistance measurement device.

A self-equalizing photo-detector (SEPD) includes, in part, a multitude of optical splitters and photo detectors, and at least one optical delay element. The first optical splitter splits an optical signal into second and third optical signals. The optical delay element delays the second optical signal to generate a fourth optical signal. The second optical splitter splits a signal representative of the fourth optical signal to generate fifth and sixth optical signals. The first photo detector receives the third optical signal via a first optical path, has an anode terminal coupled to an output terminal of the detector and a cathode terminal coupled to a first supply voltage. The second photo detector receives the sixth optical signal via a second optical path, has an anode terminal coupled to a second supply voltage and a cathode terminal coupled to the output terminal of the detector.

Nonreciprocal optical transmission devices and optical apparatuses including the nonreciprocal optical transmission devices are provided. A nonreciprocal optical transmission device includes an optical input portion, an optical output portion, and an intermediate connecting portion interposed between the optical input portion and the optical output portion, and comprising optical waveguides. A complex refractive index of any one or any combination of the optical waveguides changes between the optical input portion and the optical output portion, and a transmission direction of light through the nonreciprocal optical transmission device is controlled by a change in the complex refractive index.

Electro-optical devices and methods for constructing electro-optical devices such as a switch or phase shifter. An electrode layer is deposited on a substrate layer, a waveguide structure is deposited on the electrode layer, a first cladding layer is deposited on the waveguide structure, and the first cladding layer is planarized and bonded to a wafer. The substrate layer is removed and the electrode layer is etched to split the electrode layer into a first electrode separated from a second electrode. A second cladding layer is deposited on the etched electrode layer. The first and second electrodes may be composed of a material with a large dielectric constant, or they may be composed of a material with a large electron mobility. The device may exhibit a sandwich waveguide architecture where an electro-optic layer is disposed between two strip waveguides.

A Mach-Zehnder interferometer (MZI) filter comprising one or more passive compensation structures are described. The passive compensation structures yield MZI filters that are intrinsically tolerant to perturbations in waveguide dimensions and/or other ambient conditions. The use of n+1 waveguide widths can mitigate n different sources of perturbation to the filter. The use of at least three different waveguide widths for each Mach-Zehnder waveguide can alleviate sensitivity of filter performance to random width or temperature variations. A tolerance compensation portion is positioned between a first coupler section and a second coupler section, wherein the tolerance compensation portion includes a first compensation section having a second width, a second compensation section having a third width and a third compensation section having a fourth width, wherein the fourth width is greater than the third width and the third width is greater than the second width.

Optical inputs to photonic switches may incorporate a polarization controller in order to change the polarization of the input signal to a pre-determined polarization for operation with the silicon photonics. A last stage of components of the polarization controller may overlap with a first input switching stage. A polarization controller that overlaps with the first stage of the switch input may provide lower insertion loss and power consumption for the photonic switch.

A multimode interference (MMI) coupler with an MMI region of curved edges, and a method of design and manufacturing by using a computerized optimization algorithm to determine a favorable set of segment widths for the MMI region for a predefined set of coupler design parameters.

A projector includes an illumination waveguide layer, a collimation waveguide layer, and a spatial modulator. The illumination waveguide layer expands a light beam which is coupled to the spatial modulator. The spatial modulator modulates the expanded light beam to provide a line of light points of controllable brightness. The collimation waveguide collimates light of the light points to obtain a fan of collimated light beams. Each collimated light beam of the fan has an angle corresponding to a coordinate of the corresponding light point of the line. A tiltable reflector may be placed at the exit pupil to scan the fan of light beams in a plane non-parallel to the plane of the fan, thus providing a 2D image in angular domain. An array of Mach-Zehnder interferometers may be used in place of the illumination waveguide layer and the spatial modulator to provide the line of light points.

In one embodiment, a method of aligning mirrors of a micro-electro-mechanical system (MEMS) photonic switch includes illuminating a first group of photodiodes associated with a first mirror of a first mirror array of the MEMS photonic switch by a first control beam during a first period of time and illuminating a second group of photodiodes associated with a second mirror of the first mirror array by a second control beam during a second period of time, where the second control beam is off during the first period of time, where the first control beam is off during the second period of time, and where the second period of time is after the first period of time. The method also includes illuminating the first group of photodiodes by the first control beam during a third period of time, where the second control beam is off during the third period of time, and where the third period of time is after the second period of time.