Some embodiments are directed to a multiplexed fiber sensor for a fiber optic hydrophone array, including a signal receiver configured to receive a signal from the fiber optic hydrophone sensor array and an interferometer. The interferometer is configured to produce a first signal component and a second signal component from the signal received from the hydrophone array, and also provided with a first polarisation controller configured to control the polarisation of the first signal component and a second polarisation controller configured to control the polarisation of the second signal component. A modulated carrier signal generator configured to generate a modulated carrier signal component based on the first signal component is also provided. A detector configured to output a demodulated output signal from the modulated signal component and the second signal component is included, wherein the modulated signal component and the second signal component output separately from the interferometer.

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.

Methods and systems for selectable parallel optical fiber and WDM operation may include an optoelectronic transceiver integrated in a silicon photonics die. The optoelectronic transceiver may, in a first communication mode, communicate continuous wave (CW) optical signals from an optical source module to a first subset of optical couplers on the die for processing signals in optical modulators in accordance with a first communications protocol, and in a second communication mode, communicate the CW optical signals to a second subset of optical couplers for processing signals in the optical modulators in accordance with a second communications protocol. Processed signals may be transmitted out of the die utilizing a third subset of the optical couplers. First or second protocol optical signals may be received from the fiber interface coupled to a fourth subset or a fifth subset, respectively, of the optical couplers.

A simple, compact and low-cost passive optical transceiver device with four terminals may be used in an optical transmission system with polarization-diversity coherent detection scheme. The transceiver is composed of a first polarization splitter/combiner, a non-reciprocal polarization rotator and a second polarization splitter/combiner. The device simultaneously operates as a transmitter and a receiver with optical signals propagating along opposite directions wherein non-reciprocal polarization rotation leads to distinct effects. The received optical signal is thus split into two orthogonal polarization components directed towards two separate ports.

Provided are a small-sized optical coupling system and an optical communication device using the optical coupling system. An optical coupling system includes a liquid crystal optical element, and a photonic device having a plurality of photonic chips, and couples an optical fiber to the photonic device, in which each of the photonic chips includes a grating coupler, the liquid crystal optical element separates incident signal light depending on at least one of polarization or a wavelength to emit light in different directions, and each separated signal light component is incident into the grating coupler of the corresponding photonic chip.

An electro-optic combiner includes a polarization splitter and rotator (PSR) that directs a portion of incoming light having a first polarization through a first optical waveguide (OW). The PSR rotates a portion of the incoming light having a second polarization to the first polarization to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Each of the first and second OW's has a respective combiner section. The first and second OW combiner sections extend parallel to each other and have opposite light propagation directions. A plurality of ring resonators is disposed between the combiner sections of the first and second OW's and within an evanescent optically coupling distance of both the first and second OW's. Each of ring resonators operates at a respective resonant wavelength to optically couple light from the combiner section of the first OW into the combiner section of the second OW.

A light-receiving device includes: a light guide plate that is a transparent member having, as main surfaces, a first surface and a second surface facing each other and has an emission end formed on at least one end portion of the light guide plate; a wave plate that is disposed on the first surface of the light guide plate and converts an optical signal of circularly polarized light into linearly polarized light; a hologram layer that is disposed on the second surface of the light guide plate and guides a traveling direction of the optical signal converted into the linearly polarized light toward the emission end of the light guide plate; and a light receiver that receives the optical signal emitted from the emission end of the light guide plate and converts the received optical signal into an electrical signal.

A laser device for optical communication comprises a first laser unit connected to a first optical fiber for supplying a transmission laser beam thereto. wherein the laser device is configured for providing a reference laser beam in addition to the transmission laser beam. For providing the reference laser beam the laser device further includes a second laser unit connected to a second optical fiber for supplying the reference laser beam to the second optical fiber. The first laser unit is configured for providing the transmission laser beam as a linear polarized beam that is polarized in a first polarization direction, and the second laser unit is configured for providing the reference laser beam as a linear polarized beam that is polarized in a second polarization direction. The first optical fiber and the second optical fiber are formed of polarization maintaining optical fibers, and the laser device further includes a polarization combiner connected to a third polarization maintaining optical fiber for conveying the transmission laser beam and the reference laser beam to an optical output of the laser device.

An electro-optic combiner includes a polarization splitter and rotator (PSR) that directs a portion of incoming light having a first polarization through a first optical waveguide (OW). The PSR rotates a portion of the incoming light having a second polarization to the first polarization to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Each of the first and second OW's has a respective combiner section. The first and second OW combiner sections extend parallel to each other and have opposite light propagation directions. A plurality of ring resonators is disposed between the combiner sections of the first and second OW's and within an evanescent optically coupling distance of both the first and second OW's. Each of ring resonators operates at a respective resonant wavelength to optically couple light from the combiner section of the first OW into the combiner section of the second OW.

In various embodiments, a beam-parameter adjustment system and focusing system alters a spatial power distribution of a radiation beams before the beam is coupled into an optical fiber or delivered to a workpiece.