The invention relates to optical waveguide components, such as Faraday rotators and their manufacture Faraday rotators based on silicon waveguides are provided, where the waveguide has folded or wound sections that are parallel to an externally applied magnetic field.

Nonreciprocal optical transmission devices and optical apparatuses including the nonreciprocal optical transmission devices are provided. A nonreciprocal optical transmission device includes an optical input portion, an optical output portion, and an intermediate connecting portion interposed between the optical input portion and the optical output portion, and comprising optical waveguides. A complex refractive index of any one or any combination of the optical waveguides changes between the optical input portion and the optical output portion, and a transmission direction of light through the nonreciprocal optical transmission device is controlled by a change in the complex refractive index.

A Faraday rotator and an optical isolator having a high transmittance and a high Verdet constant are provided. The optical isolator includes at least a Faraday rotator that rotates a polarization plane of incident light in a non-reciprocal manner, a polarizer disposed on a light incident side of the Faraday rotator, and an analyzer disposed on a light exit side of the Faraday rotator. The Faraday rotator is made of an oxide containing ytterbium oxide (Yb.sub.2O.sub.3), and is manufactured by a ceramic manufacturing process, wherein the oxide is allowed to contain an oxide of a metal other than ytterbium, and the proportion of ytterbium in all metal atoms in the oxide is 80% or more.

Provided a two-dimensional photonic crystal device in which are inserted three waveguides and one resonant cavity by the creation of linear and local defects. Due to the photonic band gap related to the photonic crystal, electromagnetic signals are confined to the interior of waveguides and resonant cavity. By exciting dipole modes in the resonant cavity, with orientation that depends on the intensity of the applied DC magnetic field, the present circulator device can provide the nonreciprocal transmission of signals in the clockwise and counterclockwise directions. It can fulfill the isolation function and it is fork-shaped, providing greater flexibility in the design of integrated optical communication systems.

An optical isolator on a silicon photonic integrated circuit. The optical isolator comprising: a polarization splitter; a polarization rotator; and a Faraday rotator. The Faraday rotator comprises: one or more magnets providing a magnetic field; and a silicon spiral delay line. The silicon spiral delay line being formed from a silicon waveguide shaped into a spiral region having no built-in phase shifters and a central region within the spiral region. The central region having no more than a total of 180 degree of phase shifters.

An optical isolator core includes: a first birefringent crystal, a Faraday rotator, a second birefringent crystal, and a third birefringent crystal that are successively arranged along a forward optical path. In response to forward o light and forward e light successively traveling through the aforementioned optical elements, displacements of exit points of the forward o light and the forward e light with respect to an incident point are the same, and the forward o light and the forward e light are merged as exiting forward light. In response to backward o light and backward e light successively reversely traveling through the aforementioned optical element, displacements of exit points of the backward o light and the backward e light with respect to the incident point of the forward light causes the backward o light and the backward e light to deviate from the forward optical path.

An isolator includes a first core, a second core, a nonreciprocal member, and a magnetic body. The first core and the second core extend in a first direction and are positioned side by side with a cladding therebetween in a second direction that intersects the first direction. The nonreciprocal member is in contact with at least a part of the second core while being positioned side by side with the second core in the second direction. In a magnetic field generated by the magnetic body in a portion where the nonreciprocal member is positioned, a component in a third direction perpendicular to the first direction and the second direction is greater than any component other than the component in the third direction.

A non-reciprocal phase shift device may include an optical waveguide (e.g., a silicon waveguide) on a substrate; and a magneto-optical cladding layer on the optical waveguide, wherein the magneto-optical cladding layer includes a plurality of segments arranged having alternating magnetization directions aligned transverse to a longitudinal direction of the optical waveguide.

An optical subassembly for non-reciprocal coupling of light from a planar optical waveguide output outside the optical subassembly to an optical fiber includes a carrier configured to support the optical subassembly, an optical fiber fixed to the optical subassembly, a focusing optical system consisting two foci with one focus coincident with the input of optical fiber, an optical isolator to transmit light unidirectionally between two foci, an input boundary provided by the carrier to align the optical subassembly with the planar optical waveguide output. In particular, the optical subassembly is operably configured to provide a low transmission loss for light traveling from the planar optical waveguide output to the optical fiber.

Embodiments herein relate to photonic integrated circuits with an on-chip optical isolator. A photonic transmitter chip may include a laser and an on-chip isolator optically coupled with the laser that includes an optical waveguide having a section coupled with a magneto-optic liquid phase epitaxy grown garnet film. In some embodiments, a cladding may be coupled with the garnet film, the on-chip isolator may be arranged in a Mach-Zehnder interferometer configuration, the waveguide may include one or more polarization rotators, and/or the garnet film may be formed of a material from a rare-earth garnet family. Other embodiments may be described and/or claimed.