In some examples, automatic OTDR-based testing may include determining, based on analysis of a signal that is received from a DUT that is to be monitored, whether the DUT is optically connected. Based on a determination that the DUT is optically connected, a measurement associated with the DUT may be performed.

A light source unit generates an optical signal out of a bend-insensitive (“BI”) optical fiber that is compliant with a desired encircled flux (“EF”). The unit includes a light source to generate an optical light signal and a conventional multimode optical fiber coupled to receive the optical light signal from the light source at a first end. A modal conditioner is arranged to condition the optical light signal propagating along different modes of the conventional multimode fiber. A first bend-insensitive (BI) multimode optical fiber has an input end, the input end of the first BI multimode optical fiber being coupled at a second end of the conventional multimode optical fiber to receive the conditioned optical light signal from the conventional multimode fiber. The output from the first BI multimode optical fiber outputs an optical signal having the desired EF.

A fiber optic test device is provided that includes a light source pigtailed with a first end of a non-bend insensitive multimode fiber (non-BIMMF). A second end of the non-BIMMF is fusion spliced to a first end of a reference grade bend insensitive multimode fiber (BIMMF). A reference grade optical fiber connector is attached to a second end of the BIMMF, which is coupled to a first end of a reference grade bulkhead adapter. The non-BIMMF is deformed so that a specific launch condition, such as encircled flux, is achieved at the first end of the BIMMF. A test reference cord, which contains a reference grade BIMMF having similar geometric properties as the BIMMF that is fusion spliced to the non-BIMMF, is attached to a second end of the bulkhead adapter. Modal transparency is achieved and the launch condition is maintained at the output of the test reference cord.

A photonic integrated circuit device includes a semiconductor substrate (e.g., wafer) having a chip region therein, which is bounded on at least one side thereof by a scribe line. The chip region includes an optical transmitter, an optical receiver and a test optical waveguide. This test optical waveguide is coupled to the optical transmitter and the optical receiver and overlaps the scribe line. During a substrate dicing operation, a portion of the test optical waveguide overlapping the scribe line is removed.

An OVNA system employing an array of reference delays to estimate distance-variant phase distortion in probe light during an optical-frequency sweep thereof. The estimated distance-variant phase distortion is then used to perform a phase correction for the digital electrical signals generated in response to the probe light being passed through a device under test (DUT) during the same optical-frequency sweep. Advantageously, the performed phase correction enables the OVNA system to provide a more-accurate determination of certain optical characteristics of the DUT than that achievable without such phase correction.

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.

Methods for estimating the Effective Modal Bandwidth (EMB) of laser optimized Multimode Fiber (MMF) at a specified wavelength, λ.sub.S, based on the measured EMB at a first reference measurement wavelength, λ.sub.M. In these methods the Differential Mode Delay (DMD) of a MMF is measured and the Effective Modal Bandwidth (EMB) is computed at a first measurement wavelength. By extracting signal features such as centroids, peak power, pulse widths, and skews, as described in this disclosure, the EMB can be estimated at a second specified wavelength with different degrees of accuracy. The first method estimates the EMB at the second specified wavelength based on measurements at the reference wavelength. The second method predicts if the EMB at the second specified wavelength is equal or greater than a specified bandwidth limit.

A bending applying device includes three mandrels and applies bending to an optical fiber by winding the optical fiber onto the mandrels. The mandrels are alternately arranged at predetermined intervals such that outer circumferences of adjacent mandrels in a longitudinal direction of the optical fiber face each other in a non-contact manner. A diameter of the optical fiber is D, a radius of the mandrel is r, an interval between the adjacent mandrels in the first direction is 2r + d, a direction orthogonal to the first direction is a second direction, an interval between the adjacent mandrels in the second direction is s, and an angle θ between the second direction and a common internal tangent of the adjacent mandrels is 0 degrees or more and 45 degrees or less, and the formed angle θ satisfies following formula.

[00001]$\sqrt{\left(d+D+4r\right)\left(d-D\right)+s^2}=2\left(r+\frac{D}{2}\right)\tan \theta +\frac{s}{\cos \theta }$

An integrated circuit comprises: at least one photonic layer that includes one or more optical waveguides; a first optical coupler that couples at least a first optical mode outside of the photonic layer to a first waveguide in the photonic layer; a photonic device that includes one or more ports in the photonic layer; a first multi-port optical coupler that includes three or more ports in the photonic layer, including a first port optically coupled to the first optical coupler, a second port optically coupled to a first port of the photonic device, and a third port optically coupled to a first optical reflector configured to send substantially all optical power emitted from the third port of the first multi-port optical coupler back to the third port of the first multi-port optical coupler.

Optical Time Domain Reflectometer (OTDR) trace monitoring for change of fiber and Raman gain profile with Raman amplification uses Machine Learning. The OTDR trace monitoring includes obtaining data associated with a plurality of Optical Time Domain Reflectometer (OTDR) traces each performed at a different time; responsive to changes between the plurality of OTDR traces being above a threshold, analyzing the changes between the plurality of OTDR traces with a trained machine learning model; and determining an impact factor based on the machine learning model, wherein the impact factor is a classification of the changes between the plurality of OTDR traces.