The invention relates to a beam polarization rotator, which comprises: (a) a waveguide having an input facet, an output facet, and four side facets; (b) a core material of the waveguide having a first refractive index; (c) a coating material of the side facets having a refractive index lower than said refractive index of the core material; wherein the waveguide has a cuboid-twisted shape, such that a distal portion of an originally cuboid body is twisted at an angle α about a longitudinal-central axis of the waveguides body, while a proximal portion of the body remains fixed relative to said axis, resulting in said output facet be at an offset orientation angle α relative to the orientation of said input facet.

A fiber optics polarization controller comprises: an optical fiber and multiple polarization stages. A first stage comprises: a motor having a hollow shaft spanning from a proximal end to a distal end along a rotational axis; and a fiber paddle affixed to and adapted to rotate with the hollow shaft. The fiber paddle has a ring-shaped body with two openings arranged opposite to each other around the ring-shaped body. A first opening of the fiber paddle is connected to the distal end of the hallow shaft substantially collinear with the rotational axis of the motor. The optical fiber is arranged spanning through the hollow shaft, entering the fiber paddle through the first opening, following around the ring-shaped body to form a fiber loop, and exiting the ring-shaped body through the second opening. A second stage is arranged in series with the first stage.

An optical apparatus for spectrally shaping a laser beam within a fiber MOPA laser is disclosed. The apparatus includes a birefringent optic and a linear polarizer. The laser beam is divided between two orthogonal polarization axes of the birefringent optic having polarization mode dispersion. Propagation of the laser beam through the birefringent optic causes a wavelength-dependent phase shift between components of the laser beam in the two polarization axes. A polarizing direction of the polarizer is oriented between the two polarization axes. Propagation of the polarization-dispersed laser beam through the polarizer modulates the power spectral density of a transmitted portion of the laser beam. This spectral modulation can be tuned to shape a Gaussian spectral distribution from the master oscillator into a uniform spectral distribution for amplification by the power amplifier. The uniform spectrally-shaped laser beam can be amplified to higher powers than the original Gaussian laser beam.

The present disclosure provides a polarization attenuator and a polarization attenuation method to solve the problem of polarization dependent loss of optical devices, or to be used in optical devices or systems as a polarizer structure. The polarization attenuator comprises a first main waveguide, an offset waveguide and a second main waveguide which are arranged in sequence, wherein an output surface of the first main waveguide partially overlaps an input surface of the offset waveguide; an output surface of the offset waveguide partially overlaps an input surface of the second main waveguide; the first main waveguide or the second main waveguide supports fundamental modes and supports at least one high order mode. Meanwhile, the present disclosure further provides the polarization attenuation method comprising following steps: 1) optical signals enter the first main waveguide; 2) the optical signals excite high order modes at a joint of the first main waveguide and the offset waveguide; and 3) the signals are mixed again at a joint of the second main waveguide and the offset waveguide, and power between a fundamental mode and high order modes of the offset waveguide is redistributed between the fundamental mode and the high order mode of the second main waveguide.

Disclosed is a compact on-chip polarization splitter-rotator based on a Bezier curve gradient waveguide. The Bezier curve gradient waveguide structure is a standard SOI-based wafer structure, comprising a substrate, of which the bottom layer is buried with oxide (SiO.sub.2), and the top is composed of silicon waveguides, including a common output waveguide and a specially-structured waveguide containing Bessel curve boundaries. The common waveguide structure is composed of a cuboid waveguide, and the specially-structured waveguide is composed of an input region, an output region, a width-gradient waveguide (Bezier curve gradient structure) and a coupling region, where a width of the gradient waveguide is determined by a third-order Bezier curve, and the coupling region is composed of two asymmetrical waveguide regions.

An asymmetric adiabatic polarization beam splitter integrated with a waveband filtering splitter unit and a polarization filtering splitter unit is capable of being packaged to form an integrated optical waveguide filtering chip. The waveband filtering splitter unit utilizes an adiabatic optical waveguide structure and stimulated Raman adiabatic passage on an optical waveguide to split the energy of light sources of different bands to different spaces when the light energy is performed with an adiabatic process. The polarization filtering splitter unit utilizes the two orthogonal polarization modes of an optical waveguide with birefringence to achieve a polarization-dependent mode splitting effect based on an adiabatic theory. The asymmetric adiabatic polarization beam splitter realizes the characteristics of integration and high process tolerance, and improves the mass production feasibility.

A fiber optics polarization controller comprises: an optical fiber and multiple polarization stages. A first stage comprises: a motor having a hollow shaft spanning from a proximal end to a distal end along a rotational axis; and a fiber paddle affixed to and adapted to rotate with the hollow shaft. The fiber paddle has a ring-shaped body with two openings arranged opposite to each other around the ring-shaped body. A first opening of the fiber paddle is connected to the distal end of the hallow shaft substantially collinear with the rotational axis of the motor. The optical fiber is arranged spanning through the hollow shaft, entering the fiber paddle through the first opening, following around the ring-shaped body to form a fiber loop, and exiting the ring-shaped body through the second opening. A second stage is arranged in series with the first stage.

A medical instrument is described that includes an optical source, an optical fiber, and a waveguide patterned upon a substrate. The optical fiber receives radiation from the optical source and includes a first segment and a second segment. The second segment is rotated about an optical axis relative to the first segment. The waveguide receives radiation from the optical source and guides a beam of radiation. The waveguide includes a first waveguide segment designed to impart a first differential group delay on the beam of radiation and a second waveguide segment designed to impart a second differential group delay on the beam of radiation. A sum of the first differential group delay and the second differential group delay is substantially zero.

Systems and methods for temporal amplitude modulation of an optical beam. An exemplary system may include a birefringent fiber positioned between two polarizers, or between a polarized input light source and an output polarizer. Light may enter the birefringent fiber as linearly polarized. Depending on birefringence and orientation of the birefringent fiber, the polarization state changes as the light propagates through the birefringent fiber. This changed polarization state then enters the output polarizer, for which transmission is a function of the polarization state and the relative orientation of the polarization axis. The polarization state emerging from the birefringent fiber may be changed by modulating the fiber birefringence, for example through application of an external stress. Net transmittance of the system may be varied according to a magnitude of an external force (e.g., pressure) to some or all of the birefringent fiber.

A light field display device comprising at least one multiplexed light field display module, the multiplexed light field display module comprising a view image generator, a waveguide, and a set of shutters spatially distributed along the waveguide, the view image generator optically coupled to the waveguide, the waveguide optically coupled to each shutter, the view image generator operable to generate a set of beams of light from one of a set of view images, the waveguide configured to transmit the set of beams along its length via internal reflection, each shutter operable to be switched between a closed state and an open state, the closed state of the shutter configured to prevent the beams from escaping the waveguide, the open state of the shutter configured to allow the beams to escape the waveguide, the module operable to generate, over time, the set of beams from a different one of the set of view images, and to open, over time, a different subset of the set of shutters, thereby to allow the set of beams escaping from the subset to correspond to a different one of the set of view images.