Disclosed herein is a monolithically integrated coherent receiver chip which has a geometric arrangement of the on-chip components that significantly improves the performance and the manufacturability of a coherent receiver module for Dual Polarization Quadrature Phase Shift Keyed (DP-QPSK) applications and other optical coherent detection systems. The coherent receiver chip comprises two optical hybrids, three optical inputs and eight electrical outputs with the two optical hybrids oriented perpendicular to the optical inputs and the electrical outputs which are widely spaced and arranged in a co-linear fashion that simplifies module design and assembly. The proposed geometric arrangement also replaces any optical waveguide crossings with vertical electrical-optical crossings and includes electrical transmissions which are used to minimize channel skew. The proposed configuration also has the additional benefit of improved thermal management by separating the module's trans-impedance amplifiers.

A single-fiber bidirectional optical transceiver module of the same wavelength. A sub-wavelength grating and a Faraday rotator are used, and the same element is reused to implement a polarization multiplex/de-multiplex function, so as to implement transmission and receiving of an optical signal in a small space. The single-fiber bidirectional optical transceiver module has less optical elements, a compact structure, and low cost, meeting the needs on a miniaturized, integrated, and high speed optical transceiver module for a modern optical communication system.

Aspects of the present disclosure describe methods for reducing guided acoustic wave Brillouin (GAWBS) noise in an optical fiber that may be included in an optical communications system by reducing the polarization diffusion length of the fiber by increasing the birefringence of the optical fiber, the increased birefringence of the optical fiber being increased with respect to its average magnitude. Additionally, the polarization diffusion length is reduced by reducing the coherence length of birefringence of the optical fiber.

A coherent receiver comprising: a signal port receiving the signal light that has two polarization components at right angles each other; a polarization dependent beam splitter (PBS) that splits the signal light into two portions depending on the polarizations contained in the signal light; a beam splitter (BS) that splits the local light into two portions; a multi-mode interference (MMI) device that interferes between one of the two portions of the signal light and one of the two portions of the local light; optical components provided between the PBS and the MMI device; and wherein the PBS splitting a first wavelength range of the signal light and a second wavelength range outside the first wavelength range.

An optical module includes a first optical splitting element to split a signal beam into a first polarization component and a second polarization component, a first element having a first introduction port, a second element having a second introduction port, a first condensing part disposed between the first optical splitting element and the first introduction port and configured to condense the first polarization component toward the first introduction port, and a second condensing part disposed between the first optical splitting element and the second introduction port and configured to condense the second polarization component toward the second introduction port. An average refractive index of the second condensing part in an optical axis direction is larger than an average refractive index of the first condensing part in an optical axis direction.

An electro-optic receiver includes a polarization splitter and rotator (PSR) that directs incoming light having a first polarization through a first end of an optical waveguide, and that rotates incoming light from a second polarization to the first polarization to create polarization-rotated light that is directed to a second end of the optical waveguide. The incoming light of the first polarization and the polarization-rotated light travel through the optical waveguide in opposite directions. A plurality of ring resonators is optically coupled the optical waveguide. Each ring resonator is configured to operate at a respective resonant wavelength, such that the incoming light of the first polarization having the respective resonant wavelength optically couples into said ring resonator in a first propagation direction, and such that the polarization-rotated light having the respective resonant wavelength optically couples into said ring resonator in a second propagation direction opposite the first propagation direction.

A positioning member for positioning optical components includes a laminated body in which a plurality of thin metal plates is laminated. In the positioning member for positioning the optical components by an upper surface of a first plate forming the laminated body and a side surface of a second plate disposed above the first plate, a portion where two non-parallel side surfaces of the second plate for positioning the optical components cross each other includes a cutout portion including a crossing portion of the side surfaces.

An optical module includes a base having a first surface, a board having a second surface and a third surface, an optical circuit element having a fourth surface, a fifth surface and two ports, and an array lens. The first surface is joined to the second surface by a first solder. The third surface has a first metallic pattern and a second metallic pattern that are joined to the fourth surface by a second solder. The array lens is fixed onto the first surface of the base so as to be optically coupled to the two ports provided at one end of the optical circuit element in the first direction. The first metallic pattern is formed closer than the second metallic pattern to the one end of the optical circuit element in the first direction and is formed between the two ports in the second direction.

An optical coupling device can couple incident light from a fiber into waveguides, but can reduce the coupling of return light from the waveguides into the fiber. A Faraday rotator layer can rotate by forty-five degrees, with a first handedness, respective planes of polarization of incident beams, and can rotate by forty-five degrees, with a second handedness opposite the first handedness, respective planes of polarization of return beams. A redirection layer can include at least one grating coupler that can redirect an incident beam of one polarization so that the redirected path extends within the redirection layer toward a first waveguide, and can redirect an incident beam of an opposite polarization so that the redirected path extends within the redirection layer toward a second waveguide. An optional birefringent layer can spatially separate incident beam having different polarizations, so that two single-polarization grating couplers can be used.

Disclosed are an optical assembly and a manufacturing method therefor. The optical assembly comprises a laser component (2) and a crystal (1). The crystal (1) is disposed on the laser component (2). The laser component (2) is used to produce a laser beam. The crystal (1) is used to split the laser beam incident onto the crystal (1) so as to generate a first beam (15) and a second beam (16). The first beam (15) is used for front light emission and the second beam (16) is used for backlight monitoring. The optical assembly can split a laser beam to achieve the backlight monitoring function without adding a splitter film. It has good stability in light splitting and reduces the risk of failure in an optical device.