An optical wavelength demultiplexer includes a wavelength demultiplexing device, a first wavelength filter and a first- and second-stage wavelength sub-filters. The wavelength demultiplexing device demultiplexes an input light into a first wavelength band including wavelengths λ.sub.1 and λ.sub.2 in the vicinity of 1310 nm and a second wavelength band including a wavelength λ.sub.3 of 1490 nm and a wavelength λ.sub.4 of 1550 nm to output. The first-stage wavelength sub-filter removes the wavelength λ.sub.2 longer than 1310 nm from the second wavelength band and transmits the wavelength λ.sub.3 of 1490 nm. The second-stage wavelength sub-filter removes the wavelength λ.sub.4 of 1550 nm and outputs the wavelength λ.sub.3 of 1490 nm, which is the remainder of the selected lights, with a sufficient wavelength spectral purity.

A beam scanner and a display device is based on a photonic integrated circuit coupling light to a pair of opposed reflectors. One reflector is tiltable and has an opening through which the light is coupled, and the other reflector is configured to focus light, e.g. a concave reflector. A polarization folding configuration is used to cause the focused light propagate through the opening in the first reflector, get collimated by the second reflector, get scanned by the first reflector, and propagate through the second reflector to a pupil-replicating lightguide which provides multiple laterally offset parallel portions of the scanned beam.

An optical demultiplexer/multiplexer, comprising: a multimode interference waveguide; at least one first coupling waveguide which meets the multimode interference waveguide at at least one first location and a plurality of second coupling waveguides which meet the multimode interference waveguide at a plurality of second locations which are spaced in a direction of transmission in relation to the at least one first location, with the at least one first coupling waveguide and the second coupling waveguides together with the multimode interference waveguide providing a first angled multimode interferometer which operates to demultiplex a first optical signal having optical channels of a plurality of wavelengths or multiplex optical signals of a plurality of wavelengths into a first optical signal having optical channels of the plurality of wavelengths; at least one third coupling waveguide which meets the multimode interference waveguide at at least one third location and a plurality of fourth coupling waveguides which meet the multimode interference waveguide at a plurality of fourth locations which are spaced in a direction of transmission in relation to the at least one third location, with the at least one third coupling waveguide and the plurality of fourth coupling waveguides together with the multimode interference waveguide providing a second angled multimode interferometer which operates to demultiplex a second optical signal having optical channels of a plurality of wavelengths or multiplex optical signals of a plurality of wavelengths into a second optical signal having optical channels of the plurality of wavelengths; whereby the demultiplexer/multiplexer provides for the demultiplexing/multiplexing of first and second optical signals having optical channels of a plurality of wavelengths. In a further embodiment the first coupling waveguide of an optical demultiplexer/multiplexer comprising

A photonic integrated circuit is presented that includes a substrate, and a first and second waveguide patterned on the substrate. The first waveguide guides an input beam of radiation. The photonic integrated circuit also includes a coupling region, wherein the first and second waveguides each pass through the coupling region. One or more modulating elements are coupled to each of the first and second waveguides. The first waveguide and the second waveguide have a first facet and a second facet, respectively, and first and second reflections are generated at the first and second facets within the first and second waveguides, respectively. The one or more modulating elements coupled to each of the first and second waveguides are designed to adjust the phase of the first and second reflections before the first and second reflections pass through the coupling region.

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.

Provided are a practical rib type optical waveguide in which polarization dependence and wavelength dependence and the like are small and an optical multiplexer/demultiplexer using the same. An optical waveguide type optical multiplexer/demultiplexer of the present invention includes a substrate, M input optical waveguides and N output optical waveguides including a single mode rib type optical waveguide, multi-mode optical interference regions including a rib type optical waveguide, and reversible tapered regions that smoothly connect the input/output optical waveguides to the multi-mode optical interference regions and include M×N rib type optical waveguides, and both side surfaces of the multi-mode optical interference region are respectively formed in a stepped shape.

A silicon photonics based temperature-insensitive delay line interferometer (DLI). The DLI includes a first arm comprising a first length of a first material characterized by a first group index corresponding to a first phase delay to transfer a first light wave with a first peak frequency and a second arm comprising a second length of a second material characterized by a second group index corresponding to a second phase to transfer a second light wave with a second peak frequency with a time-delay difference relative to the first light wave. The first phase delay and the second phase delay are configured to change equally upon a change of temperature. The time-delay difference between the first light wave and the second light wave is set to be inversed value of a free spectral range (FSR) to align at least the first peak frequency to a channel of a designated frequency grid.

An approach to proving a flexible grid architecture for time and wavelength division multiplexed passive optical networks is described. One embodiment includes an optical transmitter array configured to transmit an optical signal, an optical combiner coupled to the optical transmitter array configured to receive unlocked wavelengths from the optical transmitter array and output a single optical signal, and an optical amplifier coupled to the optical combiner configured to boost downstream optical power. In some embodiments, a WDM filter is coupled to the optical amplifier, and a tunable optical network unit (ONU) coupled to the WDM filter is configured to transmit and receive the optical signals. In still other embodiments, a cyclic demultiplexer is coupled to the optical splitter and connects to an optical receiver array configured to receive optical signals.

Embodiments of techniques for inverse design of physical devices are described herein, in the context of generating designs for photonic integrated circuits (including a multi-channel photonic demultiplexer). In some embodiments, an initial design of the physical device is received, and a plurality of sets of operating conditions for fabrication of the physical device are determined. In some embodiments, the performance of the physical device as fabricated under the sets of operating conditions is simulated, and a total performance loss value is backpropagated to determine a gradient to be used to update the initial design. In some embodiments, instead of simulating fabrication of the physical device under the sets of operating conditions, a robustness loss is determined and combined with the performance loss to determine the gradient.

A multi-channel laser source, including: a bus waveguide coupled, at an output end of the bus waveguide, to an output of the multi-channel laser source; a first semiconductor optical amplifier; a first back mirror; a first wavelength-dependent coupler, having a first resonant wavelength, on the bus waveguide; a second semiconductor optical amplifier; a second back mirror; and a second wavelength-dependent coupler, on the bus waveguide, having a second resonant wavelength, different from the first resonant wavelength. In some embodiments the first semiconductor optical amplifier is coupled to the bus waveguide by the first wavelength-dependent coupler, which is nearer to the output end of the bus waveguide than the second wavelength-dependent coupler, the second semiconductor optical amplifier is coupled to the bus waveguide by the second wavelength-dependent coupler, and the first wavelength-dependent coupler is configured to transmit light, at the second resonant wavelength, along the bus waveguide.