Sumitomo Electric Industries, Limited

Shinji Endo

Motoki Kakui

Shinji Ishikawa

Yoshiaki Nagao

Toshio Oshima

Toshiyuki Yamamoto

Masakazu Shigehara

Yuichi Ohga

Tadashi Enomoto

Masahiro Takagi

Toshimi Suzuki

An optical fiber inspecting system comprises a waveform measuring unit for measuring an OTDR waveform for an optical fiber and a waveform evaluating unit for evaluating an anomaly within the optical fiber through a use of the measured waveform. The waveform evaluating unit comprises a calculating part and a detecting part. The calculating part calculates the gradient and the amount of change in gradient of the waveform at each time point by means of a gradient calculating section and a gradient change amount calculating section. The detecting part determines whether or not the gradient and the amount of change in gradient are within a defined allowable range of gradient and a defined allowable range of amount of change, respectively, by way of a gradient determining section and a gradient change amount determining section.

Method for selection of optical fiber and system for inspection of optical fiber

An optical fiber inspecting systemA comprises a waveform measuring unitfor measuring an OTDR waveform for an optical fiber F to be inspected and a waveform evaluating unitfor evaluating an anomaly within the optical fiber. The waveform evaluating unitcomprises a calculating partand a detecting partThe calculating partcalculates the gradient and the amount of change in gradient of the waveform at each time point. The detecting partdetermines whether or not the gradient and the amount of change in gradient are within a defined allowable range of gradient and a defined allowable range of amount of change, respectively. This realizes an optical fiber inspecting system, an inspection method and a selecting method, all of which enable to detect reliably an anomaly within an optical fiber through an OTDR waveform.

An optical fiber for optical amplification used for 1.58 &mgr;m band signal light amplification, at least a core region thereof being doped with Er has a core region at least a part thereof made of silica glass co-doped with Ge and Al together with Er, and Er average atomic concentration in the core region is from 1000 wt-ppm to 3000 wt-ppm inclusive, and cutoff wavelength is from 1.3 &mgr;m to 1.5 &mgr;m inclusive.

Optical fiber for optical amplifier and fiber optic amplifier

Disclosed are an optical amplifier and an optical transmission system using the same in which not only can the dispersion of optical waveguide paths for optical amplification be easily and sufficiently compensated, but also the waveform degradation of signal light can be restrained. An optical amplifier according to one embodiment of the present invention comprises at least two erbium-doped fibers and , having erbium doped to optically amplify signal light with the pump light, and having dispersion different from each other in sign, and being connected together in series, and two pump light sources and for supplying pump light to them.

Optical amplifier and optical transmission system using same

Light-amplifying optical fiber and method of making the same

An optical fiber is for optical amplification used for 1.58 &mgr;m band signal light amplification, at least a core region thereof being doped with Er. At least a part of the core region is made of silica glass co-doped with Ge and Al together with Er. The Er average atomic concentration in the core region is from 1500 wt-ppm to 3000 wt-ppm inclusive, and cutoff wavelength is from 0.8 &mgr;m to 1.1 &mgr;m inclusive.

The present invention relates to an OFA having a high signal gain, easily manufactured, having a high mechanical strength, having a small splice loss with respect to other optical fibers, and rarely encountering the occurrence of noise at a signal wavelength. The OFA according to the present invention has a function of amplifying signals propagating therethroug by pumping light supplied thereto, and comprises, at least, a core region, an inner cladding region provided on the periphery of the core region, an outer cladding region provided on the periphery of the inner cladding region, and one or more node coupling gratings. An element for signal amplification is added to at least the core region. The core region has a structure ensuring a core mode with respect to the signals, while the inner cladding region has a structure ensuring a multi-mode with respect to the pumping light. Each of the mode coupling gratings passes core mode signals therethrough, and induces a mode coupling between the inner cladding mode and the core mode with respect to the pumping light.

Optical fiber for optical amplifier, optical fiber amplifier and optical fiber laser

The present invention relates to a fiber optic amplifier comprising a structure enabling favorable signal amplification characteristics to be maintained even in an environment exposed to radiation. The fiber optic amplifier according to the present invention comprises a bleaching system for restoring glass defects generated within an optical fiber for amplification upon exposure to ultraviolet rays. This bleaching system carries out at least one of optical bleaching and thermal bleaching for the optical fiber for amplification. The optical bleaching is effected when bleaching light having a shorter wavelength shorter and a higher power than pumping light is supplied into the optical fiber for amplification, whereas the fiber optic amplifier has a structure which can introduce and eliminate the bleaching light. On the other hand, the thermal bleaching is effected by heating the optical fiber for amplification, whereas the fiber optic amplifier comprises a structure for maintaining the surface temperature of the optical fiber for amplification within a predetermined range.

Fiber optic amplifier

An optical fiber for optical amplification used for 1.58 &mgr;m band signal light amplification, at least a core region thereof being doped with Er, wherein at least a part of the core region is made of silica glass co-doped with Ge and Al together with Er, and an average Er atomic concentration in the core region is from 950 wt-ppm to 3000 wt-ppm inclusive.

Growing community of inventors

Yokohama, Japan

Shinji Endo