The present disclosure relates to semiconductor structures and, more particularly, to waveguide attenuators and methods of manufacture. The structure includes: a main bus waveguide structure; a first hybrid waveguide structure evanescently coupled to the main bus waveguide structure and comprising a first geometry of material; and a second hybrid waveguide structure evanescently coupled to the main bus waveguide structure and comprising a second geometry of the material.

An adjustable attenuation optical unit that may include a lightguide that includes a core, wherein the core comprises an output, an input and an exterior surface; and an adjustable attenuator that is configured to define an interfacing parameter related to an area of the exterior surface thereby receiving at least some of the light that impinges on the area.

An adjustable attenuation wrap plug for insertion into a signal port at an end product includes a housing with a protruding input prong and output prong, wherein a signal cable is coupled to the input prong and the output prong. The adjustable attenuation wrap plug further includes a ratchet mechanism at least partially disposed in the housing, wherein the ratchet mechanism is configurable to alter a shape of the signal cable.

Disclosed is an optical fiber-based divergence-limiting device for limiting divergence from a first maximum divergence of input light to a second maximum divergence of output light, in which the second maximum divergence is less than the first maximum divergence.

A mode equalization filter for reducing a difference in optical power between modes of signal light propagating inside FMFs of an MDM optical transmission scheme includes an FMF on the input side, a collimating lens, an ND filter, a condensing lens, and an FMF on the output side. The ND filter includes partial ND filters combined each other and having main surfaces placed in parallel to each other, a ring portion having a low transmittance is provided in a part of the partial ND filter, and a ring portion having a low transmittance is also provided in a part of the partial ND filter. When the ring portions have different aspects, and the partial ND filters are adjusted and set to be slidable in directions of axes, respectively, the partial ND filters have a property that the transmittance of each mode of the signal light differs and can obtain a function of a variable mode equalization filter.

A fiber optic temperature sensor, a sensing head structure, and a manufacturing method are provided. The fiber optic temperature sensor includes a broad spectrum light source, a first fiber optic coupler, a spectrometer, a first sensing interferometer, and a second sensing interferometer. The first sensing interferometer and the second sensing interferometer have opposite temperature responses. A first free spectral range corresponding to the first sensing interferometer is close to but not equal to a second free spectral range corresponding to the second sensing interferometer. In the fiber optic temperature sensor, two sensing interferometers both sensitive to temperature are used, and the two sensing interferometers have opposite temperature responses, thereby achieving an enhanced vernier effect, and improving the sensitivity of temperature measurement.

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.

An apparatus for an attenuation adjustment tool, the attenuation adjustment tool includes a body with an adjustment arm positioned at a first side of the body, where an actuator is configured to extend and retract the adjustment arm. The attenuation adjustment tool further includes an input port and an output port positioned at the first side of the body, wherein an input prong and an output prong of a wrap plug are each respectively insertable into the input port and the output port. The attenuation adjustment tool further includes the adjustment arm configurable to engage with a mechanism on the wrap plug, wherein the mechanism is configurable to alter a shape of a signal cable in the wrap plug.

The present disclosure provides a MEMS-based variable optical attenuator (VOA) array, sequentially including an optical fiber array, a micro-lens array, and a MEMS-based micro-reflector array to form a VOA array having several optical attenuation units. The MEMS-based micro-reflectors can change the propagation direction of a beam, causing a misalignment coupling loss to the beam and thereby achieving optical attenuation, with a broad range of dynamic attenuation, low polarization dependent loss and wavelength dependent loss, good repeatability, short response time (at the millisecond level), etc. Arrayed device elements are used as assembly units of the present disclosure, and the assembly of arrayed elements facilitates tuning in batches. Accordingly, automation levels are improved, and the production costs are reduced.

An optical part includes: an optical fiber having a core portion and a cladding portion that is formed around the core portion; a light absorber placed around the optical fiber; and an adhesive member that adheres the light absorber and the optical fiber to each other. Further, the cladding portion includes: a main portion extending along a longitudinal direction and having a main portion cladding diameter; and an input end portion positioned closer to a light input side with respect to the main portion, and an input end face cladding diameter at an input end face of the input end portion is less than the main portion cladding diameter.