A multi-level optical signal is sampled to generate an eye diagram. The signal can be adjusted when eyes in the eye diagram have different heights. More specifically, a first value is determined, and the height of a first eye is adjusted using the first value. The first value is multiplied by a stored factor to produce a second value, and the height of a second eye is adjusted using the second value, and so on for other eyes. As a result, eye heights are the same. Similarly, optical power levels of the signal can be adjusted when the levels are not equally spaced. As a result, the optical power levels are equally spaced.

An optical communication equipment performs optical communication between a first apparatus and a second apparatus. The optical communication equipment includes a monitoring section configured to monitor a light amount during optical communication, and a control device configured to output predetermined information when the light amount is less than a first threshold value and shut off communication between the first and second apparatuses when the light amount is less than a second threshold value lower than the first threshold value.

Techniques for maintaining equipment of a PON include determining a current optical profile for each segment of a plurality of segments of a PON, and detecting that the current optical profile of a particular segment is outside of a designated operating range. Based on the detection, drifts over time of the optical profile of the segment and of optical profiles of one or more other segments that share respective common endpoints with the segment are determined and compared, and based on the comparison, a component of the PON (e.g., an endpoint or an optical fiber) is identified as requiring maintenance. Each segment's optical profile corresponds to characteristics of optical signals delivered over the segment (e.g., attenuation, changes in frequencies, changes in power outputs, etc.), and current optical profiles of the PON's segments may be repeatedly updated over time to continuously monitor for components that need maintenance.

The present invention discloses an optical signal frequency calibration method and device. The method includes: receiving a first optical signal that experiences a frequency offset and that is generated by a laser in a transmitter of an access node; receiving a reference optical signal sent by a local oscillator; calculating a difference between a specified frequency difference and a frequency difference between the reference optical signal and the first optical signal; and performing frequency calibration on the first optical signal according to the difference, modulating to-be-sent uplink data by using the calibrated first optical signal, and sending the modulated uplink data to a primary node.

There are provided an optical fiber display system and an optical fiber changeover method each enabling an efficient optical fiber changeover work. The optical fiber display system according to the present invention includes a plurality of core wire identification terminals 101. Each of the core wire identification terminals 101 includes: bent part formation units 11 configured to form a bent part at an optional position of an optical fiber 50 and to leak optical signals propagating through the optical fiber 50 from the bent part; analysis units 12 configured to acquire identification numbers of communication apparatuses (51 and 52) included in the leaked optical signals, the communication apparatuses (51 and 52) being connected to respective ends of the optical fiber 50; a communication unit 13 configured to inquire of a database 201 storing relationship between the optical fiber and the communication apparatuses about the acquired identification numbers of the communication apparatuses, and to receive an identification number of the optical fiber 50 corresponding to the acquired identification numbers of the communication apparatuses, from the database 201; and a display unit 14 configured to display the acquired identification numbers of the communication.

A method and apparatus for automatic determination of a fiber type of at least one optical fiber span used in a link of an optical network, the method comprising the steps of measuring a length of said optical fiber span; measuring a chromatic dispersion of said optical fiber span; determining a fiber dispersion profile of said optical fiber span on the basis of the measured length and the measured fiber chromatic dispersion; and determining a fiber category and/or a specific fiber type of said optical fiber span depending on the determined fiber dispersion profile.

A method of wireless communication by a transmitting sidelink user equipment (UE) determines at least one quasi-co-location (QCL) relationship between antenna ports of the transmitting sidelink UE. The QCL relationship corresponds to carrier frequency offset (CFO), average delay, delay spread, Doppler shift, and/or Doppler spread across the antenna ports of the transmitting sidelink UE. Each port maps to a different transmission and reception point (TRP). The method also indicates the QCL relationship(s) to a receiving sidelink UE. A method of wireless communication by a receiving sidelink UE receives a message from TRPs of a transmitting sidelink UE. The message indicates a QCL assumption for the TRPs. The method also individually measures reference signals received from each transmission port of the TRPs. The method may also determine whether signaling from the TRPs satisfies all conditions for the QCL assumption, and report to the transmitting sidelink UE a result of the determining.

A multi-level optical signal is sampled to generate an eye diagram. The signal can be adjusted when eyes in the eye diagram have different heights. More specifically, a first value is determined, and the height of a first eye is adjusted using the first value. The first value is multiplied by a stored factor to produce a second value, and the height of a second eye is adjusted using the second value, and so on for other eyes. As a result, eye heights are the same. Similarly, optical power levels of the signal can be adjusted when the levels are not equally spaced. As a result, the optical power levels are equally spaced.

Provided are techniques, devices and systems that enable updating of a reportable parameter table database when a reconfigured optical communication path is formed by switching performed by a branching unit in an undersea optical communication transmission system. A processor may obtain system attributes of each respective segment of a number of segments of the reconfigured optical communication path from a first end point to a second endpoint. The system attributes of each respective segment of the number of segments may be evaluated from the first end point to the second endpoint of the reconfigured optical communication path. A reportable parameter table may be generated based on the evaluated system attributes that includes a listing of operational and structural parameters of system from the first endpoint to the second endpoint of the reconfigured optical communication path.

Techniques for identifying sources of degradations within a PON include detecting a degradation pertaining to a segment of the PON and comparing the drift over time of an optical profile of the segment with respective drifts over time of optical profiles of one or more other PON segments, where pairs of segments share respective common endpoints and an optical profile of a segment corresponds to the characteristics of optical signals delivered over the segment (e.g., attenuation, changes in frequencies, changes in power outputs, etc.). The differences between the compared drift(s) over time are utilized to narrow down the candidate components (e.g., segment endpoints, optical fibers, etc.) for the source of the degradation, and may be utilized to particularly identify a particular endpoint or optical fiber as being the source. The source of the degradation may or may not be a component of the segment to which the degradation pertained.