An identification system (1) includes a transmitter (131) for transmitting pulsed light via an optical fiber (10); a receiver (132) for receiving backscattering light of the pulsed light from the optical fiber (10); a detector (133) for detecting, from the backscattering light, the condition of environment surrounding the optical fiber (10); and an identifier (320) for identifying sagging of the optical fiber (10) from a detection result by the detector (133).

According to examples, a fiber element offset length-based optical reflector peak analysis apparatus may include an optical element optically connected to a laser source that emits a laser beam. The optical element may include a pre-set offset length between a plurality of adjacent branches. The fiber element offset length-based optical reflector peak analysis apparatus may further include an optical time-domain reflectometer (OTDR) to generate, based on optical reflection signals received from corresponding optical reflectors attached to devices under test (DUTs) that are attached to the plurality of adjacent branches, an OTDR trace that qualifies each of the DUTs.

An optical detection unit detects a return light and outputs a detection signal. An optical multiplexer/demultiplexer outputs the monitoring light to the optical transmission line, and outputs the return light to the optical detection unit. A processing unit detects a first timing at which the detection signal becomes less than a first threshold value, detects a second timing at which the detection signal becomes less than a second threshold value, and calculates a first change rate of the detection signal in a period between the first and second timings. The processing unit changes the first and second threshold values to calculate the first change rate for a plurality of periods, and, when a second change rate between the first change rates in two adjacent periods is greater than a threshold value, either of the first and second timings in one period is detected as the breakage position.

A photonics integrated circuit includes a first waveguide and a second waveguide. A portion of the first waveguide has a first cladding with a first refractive index. The second waveguide includes a second cladding with a second refractive index different from the first refractive index. Also disclosed is a test circuit for a photonics integrated circuit. The test circuit can be used to determine waveguide losses, and used to tune the waveguide losses.

There is provided a test method and system for characterizing an optical fiber link. At least one OTDR acquisition or at least one OLTS acquisition is performed on the optical fiber link. From the acquisition, a value of an excess insertion loss and/or an excess optical return loss associated with the optical fiber link under test is derived, i.e. in excess of a nominal value associated with a hypothetical optical fiber link having a length corresponding to the total length of the optical fiber link under test. A rating value (e.g., as a five-star rating) or a binary pass/fail value associated with the optical fiber link under test can then be derived and displayed.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

An object of the present invention is to provide an immersion detection system and an immersion detection method capable of eliminating module replacement in the occurrence of immersion and simplifying system management. An immersion detection system according to the present invention includes: an immersion detection sensor having two optical fibers connected in series such that end faces of the two optical fibers abut on each other with a predetermined gap; an optical measurer that causes test light with a plurality of wavelengths to enter an optical transmission line having a plurality of the immersion detection sensors connected in series with optical fibers and measures a return loss of the test light at the immersion detection sensor for each of the wavelengths and for each of the immersion detection sensors; and a determiner that averages, for each of the immersion detection sensors, the return losses for the wavelengths and performs threshold determination on the presence or absence of immersion.

A multi-core fiber includes multiple optical cores, and for each different core of a set of different cores of the multiple optical cores, a total change in optical length is detected. The total change in optical length represents an accumulation of all changes in optical length for multiple segments of that different core up to a point on the multi-core fiber. A difference is determined between the total changes in optical length for cores of the set of different cores. A twist parameter and/or a bend angle associated with the multi-core fiber at the point on the multi-core fiber is/are determined based on the difference.

A system is proposed for continuously monitoring the integrity of a transmission fiber coupled to a laser source and immediately shutting down the laser source upon recognition of any type of cut, break or disconnect along the transmission fiber. A pair of monitoring photodiodes is included with the laser source and used to look at the ratio of reflected light to transmitted light, shutting down the laser if the ratio exceeds a given threshold. If a break is present, the power of the reflected light will be higher than normal, where a defined threshold is used to determine of the calculated intensity is indicative of a break. By using measurements performed in terms of decibels, the monitoring system needs only to take the difference in intensities to generate the reflection/transmission ratio output.

An object is to automatically detect a failure of an optical transmission line. A light source outputs a monitoring light. An optical detection unit detects a return light from an optical transmission line and outputs a detection signal indicating an intensity of the return light. An optical multiplexer/demultiplexer outputs the monitoring light input from the light source to the optical transmission line, and outputs the return light input from the optical transmission line to the optical detection unit. A comparator compares the detection signal with a threshold voltage and outputs a comparison signal indicating the comparison result. A processing unit detects a first timing at which the comparison signal changes, and detects a failure of the optical transmission line when the first timing is earlier than a reference timing.