A tunable optical filter integrates the functions of wavelength tuning and power isolation of back reflection. The optical signal enters a Faraday rotator twice, and isolation is provided by two birefringent crystals, having their optical axes oriented at 45 degrees with respect to each other. The two birefringent crystals are on the same side of the Faraday rotator. The integration of an optical tunable filter and an isolator function into a single packaged component helps to reduce the size and complexity of optical amplifier systems, such as EDFAs and PDFAs, operating in the 1550 nm and 1310 nm transmission bands, respectively.

A light isolator member of an embodiment of the present invention is configured to be joined to another light isolator member to serve as a part of a light isolator, the light isolator member including: a lens surface disposed in a first surface; a transmission surface disposed at a position corresponding to the lens surface in a second surface on a side opposite to the first surface; and a fitting part disposed in the second surface, the fitting part being configured for fitting to the other light isolator member.

An optical isolator for use with high power, collimated laser radiation includes an input polarizing optical element, at least one Faraday optical element, at least two reflective optical elements for reflecting laser radiation to provide an even number of passes through said at least one Faraday optical element, at least one reciprocal polarization altering optical element, an output polarizing optical element, at least one light redirecting element for remotely dissipating isolated or lost laser radiation. The isolator also includes at least one magnetic structure capable of generating a uniform magnetic field within the Faraday optical element which is aligned to the path of the collimated laser radiation and a mechanical structure for holding said optical elements to provide thermal gradients that are aligned to the path of the collimated laser radiation and that provide thermal and mechanical isolation between the magnetic structure and the optical elements.

A compact and highly efficient coupling structure for coupling between DFB-LD and Si PIC edge coupler with suppressed return loss may include a DFB-LD, a Si PIC comprising at least one input edge coupler and at least one output edge coupler, a silica cover lid disposed on the Si PIC and aligned edge to edge with the Si PIC, a single-mode fiber aligned to the at least one output edge coupler of the Si PIC, a lens disposed between the DFB-LD and the at least one input edge coupler of the Si PIC, and an isolator bonded to a facet of the at least one input edge coupler with a first volume of an index matching fluid. The lens may be configured to minimize a mismatch between an output spot size of the DFB-LD and a spot size of the at least one input edge coupler of the Si PIC.

Photonic rotators integrated on a substrate are disclosed for manipulating light polarization.

Layered coaxial transmitter optical subassemblies (TOSAs) with a support bridge therebetween may be used in an optical transmitter or transceiver for transmitting optical signals at multiple channel wavelengths. The coaxial TOSAs may include cuboid type TO laser packages having substantially flat outer surfaces that may be mounted on substantially flat outer surfaces on a transmitter or transceiver housing or on the support bridge. The support bridge supports and isolates one layer of the TOSAs mounted over another layer of the TOSAs such that the TOSAs may be stacked to fit within a small space without sacrificing optical coupling efficiency.

An optical component assembly includes a light-guiding member; a cylindrical member which retains the light-guiding member in a through hole thereof; and a projection which is provided at one end of the cylindrical member so as to extend beyond an outer periphery of the cylindrical member, and is engageable in a groove which is formed in a cylindrical shell so as to extend in an axial direction of the cylindrical shell and then turn at a distal end thereof in a circumferential direction of the cylindrical shell. By fixing the cylindrical shell to the projection, the cylindrical shell becomes attachable and detachable. It is possible to provide an optical receptacle and a transceiver module for optical communications having easy removal of foreign matters.

An optical diode (1) comprising an optical wave guide for guiding light, preferably of a light mode, with a vacuum wavelength λ.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 λ.sub.0/(5*n.sub.1) and less than or equal to 20*λ.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 λ.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*λ.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 λ.sub.0 has a strongly different absorption for left circular polarization (σ.sup.−) and the right circular polarization (σ.sup.+).

A polarization-independent, optical circulator is formed in silicon photonics. The polarization-independent, optical circulator uses an optical splitter having two couplers and two waveguides joining the two couplers. One of the two waveguides is thinner than the other to create a large effective index difference between TE and TM modes transmitted through the one waveguide. Polarization rotators, including reciprocal and/or non-reciprocal rotators, are further used to create the optical circulator.

An optical isolator 10 according to the present disclosure includes a substrate 11 and an optical waveguide 12 provided on the substrate 11. The optical waveguide 12 includes a first end part 13, a plurality of second end parts 14 arranged in an array, and at least one branching part 18 located between the first end part 13 and the plurality of second end parts 14. The optical waveguide 12 has a portion having non-reciprocity and gives different non-reciprocal phase shift amounts between the first end part 13 and at least two of the second end parts 14.