An optical signal processing apparatus includes a removal unit and a superimposition unit. The removal unit receives, from a first optical transmission path, an optical signal converted from an electrical signal, in which a first signal and a second signal having different frequencies from each other have been superimposed, and removes the second signal from the optical signal which has been input. The superimposition unit superimposes a third signal having a frequency different from a frequency of the first signal on the optical signal in which the second signal has been removed by the removal unit, and outputs the optical signal in which the third signal has been superimposed to a second optical transmission path.

An optical input polarization management device 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 so as to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Light within the first and second OW's is input to a first two-by-two optical splitter (2×2OS). A first phase shifter (PS) is interfaced with either the first or second OW. Light is output from the first 2×2OS into a third OW and a fourth OW. Light within the third and fourth OW's is input to a second 2×2OS. A second PS is interfaced with either the third or fourth OW. Light is output from the second 2×2OS into a fifth OW for further processing.

An optical input polarization management device 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 so as to provide polarization-rotated light. The PSR directs the polarization-rotated light through a second OW. Light within the first and second OW's is input to a first two-by-two optical splitter (2×2OS). A first phase shifter (PS) is interfaced with either the first or second OW. Light is output from the first 2×2OS into a third OW and a fourth OW. Light within the third and fourth OW's is input to a second 2×2OS. A second PS is interfaced with either the third or fourth OW. Light is output from the second 2×2OS into a fifth OW for further processing.

A probe of a target identification system can be extended via a first lumen of a viewing instrument, such as for illuminating an area beyond a distal end of the viewing instrument via an optical path of the viewing instrument. An optical response to the illumination of the area can be received via an optical path of the probe and can be split from other optical signals of the optical path. The optical response information can be used to identify characteristics of a target and to adjust parameters of a working instrument such as a working instrument contemporaneously using the probe.

A probe of a target identification system can be extended via a first lumen of a viewing instrument, such as for illuminating an area beyond a distal end of the viewing instrument via an optical path of the viewing instrument. An optical response to the illumination of the area can be received via an optical path of the probe and can be split from other optical signals of the optical path. The optical response information can be used to identify characteristics of a target and to adjust parameters of a working instrument such as a working instrument contemporaneously using the probe.

There are described methods and devices for intra-spacecraft communication in space, the electro-optical device having at least one of transmitting capabilities for converting a first electrical signal into a first optical signal and outputting the first optical signal within a spacecraft, and receiving capabilities for receiving a second optical signal within the spacecraft and converting the second optical signal into a second electrical signal, the electro-optical device having at least one integrated circuit dedicated to at least one of the transmitting capabilities and the receiving capabilities, the at least one integrated circuit configured for operating in an analog mode where configuration voltages for the integrated circuit are provided by analog voltage settings unaffected by radiation.

Systems, methods, and computer-readable media are described for performing link training to enable optical pass-through (OPT) capabilities of a network node. OPT capabilities may refer to on-chip wavelength routing for a multi-wavelength data input, whereby an intermediate node detects wavelengths that are intended for OPT and transparently passes the wavelengths through to downstream nodes. When executed at an intermediate network node, an OPT link training algorithm can result in the creation of one or more wavelength routing maps that associate wavelengths received on particular inputs to the node with particular outputs of the node. An intermediate node may generate a respective wavelength routing map for each transmit node from which it receives input data. The wavelength routing maps may together implement OPT capabilities at the intermediate node as each wavelength routing map may indicate the manner in which wavelengths are passed through the intermediate node for a given transmit node.

Systems, methods, and computer-readable media are described for performing link training to enable optical pass-through (OPT) capabilities of a network node. OPT capabilities may refer to on-chip wavelength routing for a multi-wavelength data input, whereby an intermediate node detects wavelengths that are intended for OPT and transparently passes the wavelengths through to downstream nodes. When executed at an intermediate network node, an OPT link training algorithm can result in the creation of one or more wavelength routing maps that associate wavelengths received on particular inputs to the node with particular outputs of the node. An intermediate node may generate a respective wavelength routing map for each transmit node from which it receives input data. The wavelength routing maps may together implement OPT capabilities at the intermediate node as each wavelength routing map may indicate the manner in which wavelengths are passed through the intermediate node for a given transmit node.

An apparatus for mitigating polarization dependent loss (PDL) in an optical signal-to-noise ratio (OSNR) of a modulated optical signal is disclosed. The apparatus may comprise a spectrum analyzer to measure an optical power spectrum of a modulated optical signal. The apparatus may also comprise a measuring unit to select a first portion of the modulated optical signal and a second portion of the modulated optical signal, where each of the first and second portions of the modulated optical signals may include an independent noise distribution indicative of PDL, and measure a time-varying parameter of the first and second portions. The apparatus may also include a signal processor to PDL in an OSNR by transforming any elliptical polarization associated with the independent noise distribution into a ball polarization, determining a correlation between time-varying parameters of the first and second portions, and calculating a PDL mitigated OSNR.

Coherent optical communications technology for recovery of 1D and 2D formatted optical signals. For example, 1D or 2D formatted signals that travel through fiber optic media may be recovered by separating the light into X- and Y-polarization components, rotating one polarization component (e.g., Y-component) into the polarization space of the other component (e.g., Y-component into the X-polarization space), delaying the rotated component enough to avoid destructive interference and combining the delayed component with the undelayed component to form a folded optical signal, which may then be processed as a X-polarized signal.