According to examples, a system for measuring polarization dependent loss (PDL) for a device-under-test (DUT) may include a tunable laser, a polarization element and a power meter. The tunable laser may emit an optical signal to sweep across an optical band at a constant rate. The polarization element may scramble polarizations states of the optical signal emitted from the tunable laser. The power meter may take power measurements associated with the optical signal emitted from the tunable laser, wherein the power measurements from the power meter are used to determine a maximum insertion loss (IL) and a minimum insertion loss (IL) associated with the device-under-test (DUT). An average insertion loss (IL) and a polarization dependent loss (PDL) for the device-under-test (DUT) may be calculated based on the maximum insertion loss (IL) and the minimum insertion loss (IL) associated with the device-under-test (DUT).

There is provided a method for measuring the PDL of a DUT as a function of the optical frequency ν within a spectral range, which uses a single wavelength scan over which the input-SOP varies in a continuous manner. The power transmission through the DUT, curve T(ν), is measured during the scan and the PDL is derived from the sideband components of the power transmission curve T(ν) that results from the continuously varying input-SOP. More specifically, the Discrete Fourier Transform (DFT) of the power transmission curve T(ν) is calculated, wherein the DFT shows at least two sidebands. At least two sidebands are extracted and their inverse DFT calculated individually to obtain complex transmissions (ν), =−J . . . J, where J is the number of sidebands on one side. The response vector |m(ν) of the DUT is derived from the complex transmissions (ν) and a matrix determined by the continuous trajectory of the SOP of the input test lightwave; and the PDL of the DUT as a function of ν (PDL curve) is derived therefrom.

A hybrid optical-electrical automated testing equipment (ATE) system can implement an optical test assembly that includes an electrical interface and an optical interface with an optical-electrical device under test. The optical assembly can include a socket on which the device is placed by the ATE system to connect electrical and optical connections. The optical connections can couple light through the socket and the optical assembly to one or more testing devices to perform efficient testing of optical devices, such as high-speed optical transceivers.

A polarization dependent loss (PDL) compensation device for an optical system can be configured to output a compensating PDL to at least partially cancel a PDL of the optical system. In certain embodiments, the device can include a first polarization controller configured to modify a state of polarization of an optical signal, a PDL emulator disposed upstream of the first polarization controller and configured to output the compensating PDL upstream of the first polarization controller, and a second polarization controller disposed upstream of the PDL emulator and configured to modify a state of polarization of the optical signal upstream of the PDL emulator.

A polarization-dependent loss (PDL) determining method includes obtaining two groups of optical powers within first duration, selecting at least one group of target optical powers that satisfy a same power constraint from the two groups of optical powers, where each group of target optical powers includes a first target power and a second target power from the two groups of optical powers, and determining a PDL of the optical device based on the at least one group of target optical powers.

A test instrument is operable to test optical components of a fiber optic network. The test instrument includes a laser having a back-facet monitor. The test instrument measures a performance parameter of an optical component being tested based on optical power of the laser measured by the back-facet monitor. The performance parameter is determined based on optical power measurements that account for drift of the laser.

There is provided a method for measuring the PDL of a DUT as a function of the optical frequency ν within a spectral range, which uses a single wavelength scan over which the input-SOP varies in a continuous manner. The power transmission through the DUT, curve T(ν), is measured during the scan and the PDL is derived from the sideband components of the power transmission curve T(ν) that results from the continuously varying input-SOP. More specifically, the Discrete Fourier Transform (DFT) of the power transmission curve T(ν) is calculated, wherein the DFT shows at least two sidebands. At least two sidebands are extracted and their inverse DFT calculated individually to obtain complex transmissions (ν), =−J . . . J, where J is the number of sidebands on one side. The response vector |m(ν) of the DUT is derived from the complex transmissions (ν) and a matrix determined by the continuous trajectory of the SOP of the input test lightwave; and the PDL of the DUT as a function of ν (PDL curve) is derived therefrom.

A polarization dependent loss (PDL) compensation device for an optical system can be configured to output a compensating PDL to at least partially cancel a PDL of the optical system. In certain embodiments, the device can include a first polarization controller configured to modify a state of polarization of an optical signal, a PDL emulator disposed upstream of the first polarization controller and configured to output the compensating PDL upstream of the first polarization controller, and a second polarization controller disposed upstream of the PDL emulator and configured to modify a state of polarization of the optical signal upstream of the PDL emulator.

A polarization-dependent loss (PDL) determining method includes obtaining two groups of optical powers within first duration, selecting at least one group of target optical powers that satisfy a same power constraint from the two groups of optical powers, where each group of target optical powers includes a first target power and a second target power from the two groups of optical powers, and determining a PDL of the optical device based on the at least one group of target optical powers.

A present embodiment relates to a MDL measurement method and the like including a structure for enabling MDL measurement without increasing a processing load. The present embodiment sequentially executes, for N (≥2) spatial modes, light-input operation of inputting light of a predetermined intensity to an arbitrary spatial mode, and intensity measurement operation of measuring an output light intensity of each of the N spatial modes including the arbitrary spatial mode, to generate a transfer matrix relating to transmission loss in an optical fiber as a measurement target, and determine at least a linear value of MDL per unit fiber length by using each component value of the generated transfer matrix.