An apparatus includes a first modulator configured to modulate a radio frequency (RF) input signal onto a first optical signal and a second modulator configured to modulate a local oscillator (LO) signal onto a second optical signal. The apparatus also includes a photonic integrated circuit having an optical demodulator configured to generate, using the modulated optical signals, I and Q signals representing a demodulated version of the RF input signal. The optical demodulator may include an optical filter bank having multiple optical filters, where different optical filters are configured to pass different frequencies or frequency ranges. The optical filters may include at least one narrowband optical filter and/or one or more tunable optical filters. The narrowband optical filter(s) may be configured to isolate global navigation satellite system-related signals. The tunable optical filter(s) may be configured to isolate signals over a frequency range of about 900 MHz to about 12 GHz.

Provided is a mode equalization filter that reduces a light intensity difference between multiple modes of signal light propagating in a core of a few-mode fiber. The mode equalization filter according to the present invention includes: a collimator lens that collimates the signal light emitted from the few-mode fiber; a partial ND filter including a small dot having small transmittance with respect to the collimated signal light; and condensing lenses that condense the signal light transmitted through the partial ND filter on the few-mode fiber. The small dot having the small transmittance is arranged in a part of the partial ND filter, and the partial ND filter is arranged such that, when the collimated signal light is transmitted, a part of the collimated signal light overlaps with the small dot having the small transmittance.

An optical apparatus comprises a waveguide and a plurality of optical components disposed in the waveguide. The optical components disposed in the waveguide direct light rays indicative of an image through at least a portion of the waveguide. The optical components can be configured to preserve a wave front of the represented image. In various embodiments, the optical elements are at least one of lenses, mirrors, and filters. Various methods of making and using the optical apparatus are disclosed herein.

A fiber mode sorter includes an optical fiber including a waveguide structure configured to maintain an orbital angular momentum (OAM) of a beam propagating through the optical fiber, and an OAM mode sorter placed on a core of the optical fiber.

A filter device including a filter and waveguide tubes broadens a band in which return loss is small. A filter device (1) includes: a filter (11) including wide walls (13, 14) and narrow walls (16); and first and second waveguide tubes (21, 31). The filter 11 includes first and second columnar conductors (pins 18 and 19) each passing through an opening (13a1 or 13a2) which is provided in the wide wall (conductor layer 13) and having one end portion (181, 191) located inside the substrate (12). The first and second waveguide tubes (21, 31) are placed such that each of the first and second columnar conductors (pin 18, 19) passes through an opening (22a, 23a) and such that another end portion (182, 192) of each of the columnar conductors (pin 18, 19) is located inside the waveguide tube (21, 31).

An apparatus includes a first modulator configured to modulate a radio frequency (RF) input signal onto a first optical signal and a second modulator configured to modulate a local oscillator (LO) signal onto a second optical signal. The apparatus also includes a photonic integrated circuit having an optical demodulator configured to generate, using the modulated optical signals, I and Q signals representing a demodulated version of the RF input signal. The optical demodulator may include an optical filter bank having multiple optical filters, where different optical filters are configured to pass different frequencies or frequency ranges. The optical filters may include at least one narrowband optical filter and/or one or more tunable optical filters.

The narrowband optical filter(s) may be configured to isolate global navigation satellite system-related signals. The tunable optical filter(s) may be configured to isolate signals over a frequency range of about 900 MHz to about 12 GHz.

A fiber-based sensor and a method of forming a fiber-based sensor using microsphere lithography techniques in which a microsphere array is applied to a surface of a tip of an optical fiber to provide for microsphere lithography fabrication of a desired pattern on the tip of the optical fiber. The characteristics of the pattern define sensing capabilities of the sensor to provide for chemical and/or biological sensing.

A system that uses a scalable array of individually controllable laser beams that are generated by a fiber array system to process materials into an object. The adaptive control of individual beams may include beam power, focal spot width, centroid position, scanning orientation, amplitude and frequency, piston phase and polarization states of individual beams. Laser beam arrays may be arranged in a two dimensional cluster and configured to provide a pre-defined spatiotemporal laser power density distribution, or may be arranged linearly and configured to provide oscillating focal spots along a wide processing line. These systems may also have a set of material sensors that gather information on a material and environment immediately before, during, and immediately after processing, or a set of thermal management modules that pre-heat and post-heat material to control thermal gradient, or both.

Light diffusing optical fibers for use in illumination applications and which have a uniform color gradient that is angularly independent are disclosed herein along with methods for making such fibers. The light diffusing fibers are composed of a silica-based glass core that is coated with a number of layers including both a scattering layer and a phosphor layer.

In one embodiment, a device receives optical time domain reflectometer (OTDR) trace samples, each sample labeled with an associated fiber optic cable condition. The device alters the received OTDR trace samples to generate a set of synthetic OTDR trace samples. Each synthetic sample is labeled with the label of the received sample that was altered to generate the synthetic sample. The device trains a machine learning-based classifier using a training dataset that comprises the synthetic OTDR trace samples. The device uses the trained classifier to identify a condition along a particular fiber optic cable based on OTDR trace data obtained from that cable.