A second transceiver (22) includes a guide light source (22c), a photorefractive crystal (22a), and a frequency control unit (22e). The guide light source (22c) emits guide light (Y3). A double phase conjugate mirror (22m) is formed in a crystal (22a) by scattering of reference signal light (Y1), which has a frequency different from that of the guide light and is incident on the crystal via space (15) after being transmitted from a first transceiver (21) which is a transceiver on the other side, and the guide light that is incident on the crystal in a reverse direction to that of the reference signal light. A frequency control unit (22e) couples the reference signal light emitted from the crystal (22a), which is phase-conjugate light of the guide light generated by the mirror (22m), to an optical fiber (13b).

A system for communication is provided. The system includes an emitter transmitting a first code of a first wavelength. The system includes a filter or variable waveplate receiving the first code. The system includes a receiver sensor receiving the filtered first code. The system includes the emitter transmitting a second code of a second wavelength. The system includes the variable waveplate or other filter receiving the second signal. The system includes the receiver sensor receiving the filtered second code. The first and second codes may be used for communication, synchronizing the emitter, and other purposes.

In order to improve free space optical communications, an optical communication terminal includes a laser source, a photo detecting apparatus and an optical input/output assembly. These components are controlled by a control logic. In order to have the optical communication terminal to be self-compatible, the optical input/output assembly selectively routes the outgoing beam and incoming beam depending on their respective beam polarization. To this end, the optical input/output assembly may include a polarizing beam splitter together with a quarter-wave plate.

An optical transmission device includes a first wavelength multiplexer, a second wavelength multiplexer, a wavelength converter and a third wavelength multiplexer. The first wavelength multiplexer multiplexes optical signals in a first wavelength band to generate first wavelength multiplexed light. The second wavelength multiplexer multiplexes optical signals in the first wavelength band to generate second wavelength multiplexed light in a first polarization. The wavelength converter converts a wavelength of the second wavelength multiplexed light from the first wavelength band into a second wavelength band by a cross phase modulation among the second wavelength multiplexed light, first pump light in a second polarization and second pump light in the second polarization. The second polarization is orthogonal to the first polarization. The third wavelength multiplexer multiplexes the second wavelength multiplexed light whose wavelength has been converted by the wavelength converter and the first wavelength multiplexed light.

A High Bandwidth Individual Channel Control via Optical Reference Interferometry (HICCORI) system actively controls the phase and/or polarization of the optical emission of each element in a tiled optical array. It can also actively align any high-frequency broadening waveform applied to the array beams for spectral broadening or data transmission. By maintaining consistent polarization and manipulating the phase relationships of the beams emitted by the array elements, the HICCORI system can manipulate the spatial pattern of constructive and destructive interference formed as the individual emissions coherently combine. Active feedback control allows the desired phase, polarization, and/or spectral broadening alignment to be maintained in the presence of external disturbances.

An optical bench utilizing narrowband optical filters on precision rotary stages that can provide custom tuning of the operational frequencies of the optical bench while maintaining the ability to switch between narrowband and wideband operation thereof. The precision rotary filters may further provide dynamic reconfiguration of the optical bench to alternate frequencies for intersystem compatibility, the enablement of additional self-test capabilities, and easing the manufacturing tolerances thereof.

Radiation receiver apparatus with a radiation receiver and a radiation entrance face, wherein the radiation receiver includes an active region that detects radiation with a target wavelength in the near-infrared, an optical element is arranged between the radiation entrance face and the radiation receiver, an optical axis of the optical element extends through the radiation receiver, the optical element is shaped and arranged relative to the radiation receiver such that, of radiation incident on the radiation entrance face at an angle of greater than or equal to 40° to the optical axis, at most 10% is incident on the radiation receiver, and a visible light filter is formed between the radiation receiver and the radiation entrance face.

A loss-based wavelength meter includes a first photodiode configured to measure power of monochromatic light; and a loss section having a monotonic wavelength dependency, wherein a wavelength of the monochromatic light is determined based on measurements of the first photodiode after the monochromatic light has gone through the loss section. This provides a compact implementation that may be used in integrated optics devices using silicon photonics as well as other embodiments.

A transmission method and system for an optical burst transport network are disclosed in the present document. The method includes: acquiring a topology of a mesh OBTN network, and generating one or more logical sub-networks according to the topology of the mesh OBTN network; a predetermined master node in the mesh OBTN network updating bandwidth maps for all logical sub-networks; the predetermined master node is a node, which all control channels pass through, in all the nodes of the mesh OBTN network.

An optical transmission device includes a first wavelength multiplexer, a second wavelength multiplexer, a wavelength converter and a third wavelength multiplexer. The first wavelength multiplexer multiplexes optical signals in a first wavelength band to generate first wavelength multiplexed light. The second wavelength multiplexer multiplexes optical signals in the first wavelength band to generate second wavelength multiplexed light in a first polarization. The wavelength converter converts a wavelength of the second wavelength multiplexed light from the first wavelength band into a second wavelength band by a cross phase modulation among the second wavelength multiplexed light, first pump light in a second polarization and second pump light in the second polarization. The second polarization is orthogonal to the first polarization. The third wavelength multiplexer multiplexes the second wavelength multiplexed light whose wavelength has been converted by the wavelength converter and the first wavelength multiplexed light.