An heterodyne apparatus and method for measuring performance parameters of a coherent optical receiver at RF frequencies is disclosed. Two coherent lights are launched into signal and LO ports of the receiver with an optical frequency offset f. One of the lights is modulated in amplitude at a test modulation frequency F. COR performance parameters are determined by comparing two frequency components of the COR output. CMRR is determined based on a strength of a direct detection spectral line at the modulation frequency relative to that of spectrally-shifted lines at (F±f). GDV information is obtained by modulating one of the lights at two phase-locked frequencies, such as F and 2F, and comparing phases of two time-domain traces corresponding to frequency components of the COR output signal at the two frequencies.

An heterodyne apparatus and method for measuring performance parameters of a coherent optical receiver at RF frequencies is disclosed. Two coherent lights are launched into signal and LO ports of the receiver with an optical frequency offset f. One of the lights is modulated in amplitude at two phase-locked modulation frequencies F.sub.1 and F.sub.2. COR performance parameters are determined by comparing two frequency components of the COR output. The group delay variation (GDV) information is obtained by comparing phases of two time-domain traces corresponding to frequency components of the COR output signal at the two modulation frequencies shifted by the optical frequency offset f.

Raman amplifier systems and methods with an integrated Optical Time Domain Reflectometer (OTDR) for integrated testing functionality include an amplifier system, an OTDR and telemetry subsystem, and a method of operation. The OTDR and telemetry subsystem is configured to operate in an OTDR mode when coupled to a line in port and to operate in a telemetry mode when coupled to a line out port. The OTDR and telemetry subsystem enables on-demand fiber testing while also operating as a telemetry channel that is both a redundant optical service channel (OSC) and provides a mechanism to monitor Raman gain over time. The OTDR and telemetry subsystem minimizes cost and space by sharing major optical and electrical components between the integrated OTDR and other functions on the Raman amplifier.

Provided are a light transmission device and a control method of same which can switch a processing sequence according to a vendor of an optical module to be mounted thereon. The light transmission device, which is provided with ports on which optical modules which transmit an optical signal are mounted, is additionally provided with: a storage means for holding a table in which processing sequences respectively corresponding to pieces of identification information about the optical modules are stored; and a control means for acquiring pieces of identification information about the mounted optical modules, determining, with reference to the table, a processing sequence corresponding to the identification information about the acquired optical module, and executing the determined processing sequence for the optical module.

An apparatus and method for measuring frequency response characteristics of an optical transmitter and an optical receiver where the apparatus includes: a generating unit configured to generate a driving signal for driving the modulator of the optical transmitter, which comprises at least two frequencies; and a calculating unit configured to respectively calculate the frequency response characteristics of the optical transmitter and the optical receiver according to output signal components in output signals of the optical receiver corresponding to at least two detection signal components of identical amplitudes and different frequencies in detection signals. The frequency response characteristics of the optical transmitter and the optical receiver may be obtained, the amplitude responses and phase responses in the frequency response characteristics may be respectively obtained, and the measurement results are accurate and reliable.

A Pulse Amplitude Modulated (PAM) optical device utilizing multiple wavelengths, features a communications interface having enhanced diagnostics capability. New registers are created to house additional diagnostic information, such as error rates. The diagnostic information may be stored in raw form, or as processed on-chip utilizing local resources.

Embodiments of the present invention disclose a method. The method includes determining, by an OLT, that an ONU goes offline, and sending to the ONU corresponding to an ONU identifier, a detection message that carries the ONU identifier, where the ONU identifier is an ONU identifier that is occupied before the ONU goes offline and that is not reassigned, and the detection message is used to instruct the ONU corresponding to the ONU identifier to report an identification code. The method also includes receiving, a response message, where the response message carries the identification code of the ONU that sends the response message. The method also includes and determining that the ONU corresponding to the identification code carried in the response message is a rogue ONU.

Techniques are described for characterizing a receiver front end of a pluggable optical module. The pluggable optical module receives an optical signal that includes a first portion having a first polarization and a second portion having a second polarization. The first portion and second portion are not coherent with one another and the power of the first portion and second portion is equal.

A hybrid automated testing equipment (ATE) system can simultaneously test electrical and optical components of a device under test, such as an optical transceiver. The device under test can be a multilane optical transceiver that transmits different channels of data on different lanes. The hybrid ATE system can include one or more light sources and optical switches in an optical test lane selector to selectively test and calibrate each optical and electrical components of each lane of the device under test.

An optical end monitoring apparatus in an optical communication network includes an optical transmitting unit, an optical receiving unit, and a decision unit. The optical transmitting unit generates first and second optical signals with different wavelengths and transmits the first and second optical signals to the optical end terminal over an optical cable. The optical receiving unit receives reflection signals corresponding to the respective first and second optical signals. The decision unit determines whether the optical end terminal is connected to the optical cable using a difference between magnitudes of the respective received reflection signals.