A two-dimensional photonic crystal in which are inserted four waveguides and a resonant cavity. Owing to the existence of the photonic band gap, an electromagnetic signal propagating through the device is confined within the guides and the cavity and, through the adjustment of the orientation of a dipole mode generated within the cavity, is able to function in three distinct regimes. In regime 1, subjected to an external DC magnetic field +H0, it functions as a two-way divider, with isolation of the input relative to the two outputs, and, upon reversal of the field signal, it functions as an optical key. In regime 2, with the use of a DC magnetic field H0, it functions as a waveguide bender, with the input isolated from the output, and, upon reversal of the field signal, functions as an optical key. In regime 3, subject to the application of an external DC magnetic field +H1, the device functions as a three-way divider.

A compact six-port Photonic Crystal (PhC) circulator includes a hexagonal PhC branch waveguide and six waveguide ports, wherein six PhC branch waveguides respectively correspond to the six waveguide ports, and the six waveguide ports respectively are symmetrically distributed at the periphery of PhCs. One second dielectric material column is arranged at the center of the hexagonal PhC waveguide. Six identical magneto-optical material columns respectively are arranged at first adjacent positions of the second dielectric material column. Six identical third dielectric material columns respectively are arranged at second adjacent positions of the second dielectric material column. An electromagnetic signal is inputted from any one of the waveguide ports and is outputted from the next waveguide port adjacent thereto, while the remaining waveguide ports are in a signal isolated state, thus forming unidirectional circular transmission.

An optical polarizer includes a dielectric substrate and a number of elongated dielectric ridges positioned or disposed in spaced relation on a surface of the substrate. Each dielectric ridge has a length direction, curved or straight, that extends along the surface of the substrate. Each dielectric ridge also includes a pair of spaced sides that extend away from the surface of the substrate and a top extending between the spaced sides opposite the surface of the substrate. Each side of each dielectric ridge includes an electrically conductive coating.

An optical isolator includes a polarizer for receiving an optical signal from an optical signal source, a Faraday rotator disposed on one surface of the polarizer for rotating a polarization of the optical signal output by the polarizer and outputting the same as a rotator output optical signal, and an analyzer disposed on an opposing surface of the polarizer for receiving the rotator output optical signal and for outputting at least a part thereof. The polarizer and the analyzer each include a number of spaced elongated dielectric ridges. Each dielectric ridge has a length direction extending along the one surface of the Faraday rotator, pair of spaced sides that extend away from the one surface of the Faraday rotator and a top extending between the spaced sides opposite the one surface of the Faraday rotator. Each dielectric ridge includes an electrically conductive coating on each side of the dielectric ridge.

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 microfabricated optical apparatus that includes a light source driven by a waveform, wherein the waveform is delivered to the light source by at least one through silicon via. The microfabricated optical apparatus may also include a light-sensitive receiver which generates an electrical signal in response to an optical signal. An optical source may be attached to a carrier substrate with the TOSA by a flexible connector, in order to align the optical source before affixing it permanently.

A planar lightwave circuit may include a set of components. The set of components may include an input waveguide to couple to an optical communications transceiver. The set of components may include an output waveguide to couple to the optical communications transceiver. The set of components may include a common port to couple to an optical fiber. The set of components may include a first polarization beam splitter. The set of components may include a second polarization beam splitter. The set of components may include a third polarization beam splitter. The set of components may include a rotator assembly including a Faraday rotator and a quarter-wave plate.

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.

A two-dimensional photonic crystal formed composed of a square lattice of dielectric rods immersed in air, in which are inserted, in a controlled manner, defects that originate three waveguides and one resonant cavity. The cavity is formed of a ferrite cylinder with magneto-optical properties, and by two dielectric cylinders located near to the ferrite cylinder. It has the function of transmitting electromagnetic signals in a desired direction (clockwise or counterclockwise), defined by the sign of an external DC magnetic field H.sub.0.

An optical diode (1) comprising an optical wave guide for guiding light, preferably of a light mode, with a vacuum wavelength .sub.0, wherein the optical wave guide has a wave guide core (2, 3, 14) with a first index of refraction (n.sub.1), and the wave guide core (2, 3, 14) is surrounded by at least one second optical medium which has at least one second index of refraction (n2), wherein n.sub.1>n.sub.2 applies, wherein the wave guide core (2, 3, 14) has at least in sections a smallest lateral dimension (7) which is a smallest dimension of a cross section (6) perpendicular to a propagation direction (5) of the light in the wave guide core (2, 3, 14), wherein the smallest lateral dimension (7) is greater than or equal to .sub.0/(5*n.sub.1) and less than or equal to 20*.sub.0/n.sub.1, wherein the optical diode (1) additionally comprises at least one absorber element (10, 11, 15, 16) which is arranged in a near field, wherein the near field consists of the electromagnetic field of the light of the vacuum wavelength .sub.0 in the wave guide core (2, 3, 14) and outside of the wave guide core (2, 3, 14) up to a standard interval (12) of 5*.sub.0, wherein the standard interval (12) is measured starting from one surface (8) of the wave guide core (2, 3, 14) forming an optical interface and in a direction perpendicular to the surface (8). The invention provides that the at least one absorber element (10, 11, 15, 16) for the light of the vacuum wavelength .sub.0 has a strongly different absorption for left circular polarization (.sup.) and for right circular polarization (.sup.+).