The technology employs a state-based power control loop (PCL) architecture to maintain tracking and communication signal-to-noise ratios at suitable levels for optimal tracking performance and data throughput in a free-space optical communication system. Power for a link is adjustable to stay within a functional range of receiving sensors in order to provide continuous service to users. This avoids oversaturation and possible damage to the equipment. The approach can include decreasing or increasing the power to counteract a surge or drop while maintaining a near constant received power at a remote communication device. The system may receive power adjustment feedback from another communication terminal and perform state-based power control according to the received feedback. This can include re-initializing and reacquiring a link with the other communication terminal automatically after loss of power, without human intervention. There may be a default state and discrete states including rain, fade, surge and unstable states.

An optical communication fiber link including a monitoring system connected to an optical fiber transmitting electromagnetic radiation including a communication. The monitoring system includes a detection system detecting a scattering of the electromagnetic radiation from the optical fiber. The monitoring system monitors the scattering for an abnormal change and determines, from the abnormal change, an absence or a presence of a fault in the optical fiber.

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.

This application provides an optical emission apparatus, an optical communication system, and an optical communication method. Light beams of N optical emission units in the optical emission apparatus are adjusted, so that an optical power of entering an optical receiving apparatus is maximized, and impact of a speckle caused by turbulence is minimized, thereby improving receiving efficiency of an optical antenna. The optical emission apparatus includes a first optical splitter and N optical emission units, where N is an integer greater than 1; the first optical splitter is configured to transmit received same signal light to the N optical emission units; and the N optical emission units are configured to output the signal light from the first optical splitter, to obtain light beams distributed based on a preset proportion.

An optical reception device including: a wavelength selection unit configured to split an optical signal amplified by an optical amplifier into different paths according to wavelengths by using a wavelength multiplexer/demultiplexer, and control a passage state of a passage target optical switch through which the optical signal is to be passed, out of a plurality of optical switches provided on the respective paths, to select an optical signal of a path where the optical signal entered and output the optical signal to a receiver; and a wavelength detection unit configured to detect the wavelength of an optical signal by using each of a plurality of optical detectors, determine the passage target optical switch based on a detection result, and output, to the determined passage target optical switch, a control signal for controlling the passage target optical switch so as to enter the passage state, the optical detectors being respectively provided on different paths that are different from the paths on which the plurality of optical switches are provided and that respectively correspond to wavelengths into which the optical signal is split by a wavelength multiplexer/demultiplexer.

Systems and methods for avoiding fiber damage of an optical fiber link are provided. A method, according to one implementation, includes monitoring optical signals transmitted along an optical fiber link from an output port of a first card to an input port of a second card. In response to detecting a fiber disconnection state when an amplifier of the first card is operating in a normal condition, the amplifier of the first card enters a forced Automatic Power Reduction (APR) condition. In addition to potentially reducing the risk of eye damage from laser light emitted from the optical fiber link, the forced APR condition is configured to allow for an uninterrupted debugging procedure. Also, the method includes returning the amplifier of the first card from the forced APR condition back to the normal operating condition after receiving an indication that the fiber disconnection state has cleared.

A passive optical network system includes an optical line terminator (OLT) configured to detect signal strength and a phase of a burst-mode uplink signal from each of optical network units (ONUs) to control the ONUs so as to equalize signal strengths of signals received from the ONUs and configured to control the ONUs so as to adjust a phase of each of the signals received from the ONUs, and the ONUs are each configured to control signal strength and phase of an burst-mode uplink signal and transmit a resultant burst-mode uplink signal under control of the OLT.

An apparatus for monitoring strain in an optical chip in silicon photonics platform. The apparatus includes a silicon photonics substrate shared with the optical chip. Additionally, the apparatus includes an optical input configured in the silicon photonics substrate to supply an input signal of a single wavelength. The apparatus further includes a first waveguide arm and a second waveguide arm embedded in the silicon photonics substrate to form an on-chip interferometer. The second waveguide arm forms a delay line being disposed at a region in or adjacent to the optical chip. The on-chip interferometer is configured to generate an interference pattern serving as an indicator of strain distributed at the region in or adjacent to the optical chip. The interference pattern is caused by a temperature-independent phase shift at the single wavelength of the interferometer between the first waveguide arm and the second waveguide arm.

A system installed in a cross-border area between a provider network of a provider and a customer network of a customer includes: a smart optical network termination device (NT) at a site of the customer, wherein the smart optical NT is configured to implement a demarcation point between the customer network and the provider network, and wherein the smart optical NT is independent of a data rate passing through it and an optical interface connected to it; and a monitoring device located at a point of presence (PoP) of the provider network. The smart optical NT is further configured to monitor a coupling of optical power by the customer into the provider network and to interact with the monitoring device via at least one traffic analysis point (TAP) for connectivity validation from the PoP to the demarcation point.

This application provides a port identification method, apparatus, and system, and belongs to the field of optical communications technologies. According to this application, a connection relationship between the ONT and the optical splitter and a connection relationship between the ONT and the port of the optical splitter can be accurately identified.