A mode loss difference compensator of the present disclosure includes a main waveguide configured to allow propagation of N or more modes (where N is an integer of 3 or more), a first auxiliary waveguide having, at one end thereof, a first coupling portion configured to mode-convert an LP0n mode (where n is an integer of 2 or more) propagating in the main waveguide into a fundamental mode in the first auxiliary waveguide and transfer the fundamental mode from the main waveguide to the first auxiliary waveguide and having, at the other end thereof, a second coupling portion configured to mode-convert the fundamental mode propagating in the first auxiliary waveguide into the LP0n mode (where n is an integer of 2 or more) in the main waveguide and transfer the LP0n mode from the first auxiliary waveguide to the main waveguide, and a second auxiliary waveguide having, at one end thereof, a third coupling portion configured to convert a higher-order mode, other than any LP0n mode (where n is an integer of 2 or more), propagating in the main waveguide into a fundamental mode in the second auxiliary waveguide and transfer the fundamental mode from the main waveguide to the second auxiliary waveguide and having, at the other end thereof, a terminal end portion configured to eliminate the fundamental mode propagating in the second auxiliary waveguide from the second auxiliary waveguide, wherein the main waveguide includes a loss imparting portion configured to impart a loss to a fundamental mode propagating in the main waveguide between the first and second coupling portions.

A system and a method for optical sensing of single molecule or molecules in various concentrations are provided. The optical sensor system comprises a first fiber, a second fiber, a light source and a detection device. The first fiber and the second fiber are fused together to form an optical coupler. The first fiber serves as the passageway for the analyte, while the second fiber serves as the waveguide for the light that will interact with the said analyte. One end of the second fiber is connected to the light source (e.g. laser), and the opposite end is connected to the detection device (e.g. spectrometer). The analyte is introduced into the first fiber through one of its ends, and is allowed to flow through inside the hollow core of the said first fiber. When light is delivered through the input end of the second fiber, the evanescent light is formed in the optical coupler and is allowed to interact with the analyte in the first fiber. One scenario in this analyte-light interaction results in, for example, the generation of Raman emission that is used as the probing signal. The spectrum of the Raman emission is analyzed by the detection device to determine the presence of target molecule.

A mode converter provided in the present invention includes an input multimode waveguide, an output multimode waveguide, and a first conversion waveguide, where the input multimode waveguide is configured to receive a first signal which mode is a first mode; the first conversion waveguide has an input coupling waveguide with a first effective refractive index, and has an output coupling waveguide with a second effective refractive index: the first conversion waveguide is configured to perform, by using the input coupling waveguide, evanescent wave coupling on the first signal that is in the first mode and that is transmitted in the input multimode waveguide, and couple the first signal to the second mode of the output multimode waveguide by using the output coupling waveguide, so as to obtain the first signal in the second mode; and the output multimode waveguide is configured to output the first signal in the second mode.

An electro-optic beam controller, material processing apparatus, or optical amplifier, and corresponding methods, can include an actively controlled, waveguide-based, optical spatial mode conversion device. The conversion device can include a coupler, which can be a photonic lantern, configured to combine light beams into a common light beam; a sensor configured to measure at least one characteristic of the common light beam; and a controller configured to modulate optical parameters of the individual, respective light beams to set one or more spatial modes of the common light beam. Actively controlled and modulated devices can be used to maintain a stable, diffraction-limited beam for use in an amplification, communications, imaging, laser radar, switching, or laser material processing system. Embodiments can also be used to maintain a fundamental or other spatial mode in an optical fiber even while scaling to kilowatt power.

Periscope assemblies are provided which have a light path that travels in a first plane along the first waveguide, a second plane along the second waveguide that is parallel to the first plane, and along a third plane along the third waveguide that intersects the first plane and the second plane. In some examples the periscope assembly includes first and second carriers comprising respective first and second waveguides and defining respective first and second cavities in which a third carrier comprising a third waveguide is disposed and optionally includes an optical component. In some examples, the cavities are defined in one or more carriers on a mating surface, on a side opposite to the mating surface, or on a side perpendicular to a mating surface.

An optical isolator for suppressing back reflections from a downstream optical system is described. The optical isolator includes a plurality of optical paths between a splitter and a combiner. One or more of the optical paths include two phase modulators that are driven by oscillating signals having predefined phase relationships. At least one bypass optical path does not include two phase modulators driven by oscillating signals. Amplitude and phase of an optical signal traversing the bypass optical path may be tuned to further suppress residual reflections from a downstream optical system.

An optical network having at least one star coupler comprising transmit and receive optical mixers which are respectively optically coupled to transmitters and receivers of a plurality of optical-electrical media converters. Each optical-electrical media converter comprises a respective receiver optically coupled to the receive optical mixer by way of plastic optical fibers and a respective transmitter optically coupled to the transmit optical mixer by way of plastic optical fibers. The output plastic optical fibers attached to an output face of the receive optical mixer have a diameter less than the diameter of the input plastic optical fibers attached to an input face of the receive optical mixer.

Methods, systems, and devices are disclosed for implementing a fiber-waveguide evanescent coupling. In one aspect, a device having integrated photonic components includes a substrate, a waveguide formed on the substrate to include a terminal waveguide portion that terminates at one side of the substrate, and a fiber including a fiber core and fiber cladding surrounding the fiber core, in which at least a portion of the fiber cladding is removed at or near a fiber terminal end to enable optical evanescent coupling via a side surface of the fiber core at the or near the fiber terminal end, the fiber core at the or near the fiber terminal end is placed over the one side of the substrate to be above and to overlap with the terminal waveguide portion of the waveguide to enable optical evanescent coupling via side surfaces of the fiber core and the waveguide.

A device includes an optical splitter comprising a plurality of splitter outputs. The splitter outputs are out of phase and include a non-uniform phase front. The device includes a one-dimensional phase compensation array communicating with the optical splitter. The phase compensation array receives the non-uniform phase front and outputs a uniform phase front. The phase compensation array includes a plurality of array outputs. The device includes a tunable linear gradient phase shifter communicating with said phase compensation array to impart a linearly-varying phase shift across said plurality of array outputs, thereby steering a beam along a first angle in a first plane. The device includes a waveguide grating out-coupler communicating with said linear gradient phase shifter, and a uniform phase shifter communicating with the waveguide grating out-coupler. The uniform phase shifter steers the flat phase front along a second angle in a second plane perpendicular to said first plane.

The present invention relates to an optical scanning type video projection device that decreases the height of the optical scanning type video projection device by improving the disposition of a light source module device and an optical scanning mirror device. The optical scanning type video projection device has: a first substrate on which an optical waveguide type multiplexer having a plurality of optical waveguides and a light multiplexer is provided; a second substrate on which an optical scanning mirror device having a movable mirror is provided; and an optical member configured to guide a light beam emitted from the optical waveguide type multiplexer to the movable mirror in a direction that is different from an emitting direction of the light beam. The first substrate and the second substrate are disposed in parallel with each other.