Ando Electric Company

Nippon Telegraph and Telephone Corporation

Yokogawa Electric Corporation

Rikihiro Iida

Eiji Yoshida

Masataka Nakazawa

Akio Ichikawa

Kazuhiro Ohki

Yoshihiro Kumagai

Yuka Asahina

When set values of a wavelength and a output level are input, the input set values (of the wavelength and the output level) are collated with data (A), and then, an approximate temperature of a DFB laser is calculated. The calculated approximate temperature is collated with data (B), and then, a output regulation value of the DFB laser is calculated. The input set value (the output level) is added to the power regulation value, and then, an optical output controlling value is calculated. The optical output level of the DFB laser is controlled. The optical output controlling value and the input set value (of the wavelength) are collated with the data (A), and then, a temperature controlling value of the DFB laser is calculated. Consequently, the temperature of the DFB laser is controlled.

DFB laser driving device, DFB laser driving method and storage medium

A light source is connected to a first terminal of an optical branch coupler , and a first optical sensor is connected to a second terminal. A second optical sensor is connected to a fourth terminal, and a master optical connector is connected to a third terminal. While a measured optical fiber is connected to the master optical connector , the power of light received by the first optical sensor and the power of light received by the second optical sensor are detected. The insertion loss and return loss of the optical fiber are computed from the power values of received light detected by a measurement unit

Apparatus for inspecting fiber with optical connector

An apparatus for inspecting a multi-core optical fiber having a plurality of cores arranged in one plane includes a light source having a plurality of optical output terminals which are connected to the incident ends of the respective cores of the multi-core optical fiber and used for putting optical signals into the respective cores thereof; optical signal taking means ( and ) for taking out the optical signal emitted from the emission end of each core of the multi-core optical fiber in a time series mode according to the alignment order of emission-side cores of the multi-core optical fiber; optical signal detecting means ( and ) for detecting the optical signal thus taken out by the optical signal taking means; and signal processing means for verifying core numbers of the respective cores of the multi-core optical fiber on the basis of the signal patterns of detection outputs of the optical signal detecting means.

Multi-core optical fiber inspecting method and apparatus

An apparatus for verifying the wire gauges of a multi-core optical fiber including a multi-output light source unit having a plurality of output terminals, and an integrated light receiving device having a plurality of light receiving elements which are integrated into one body. In the apparatus, outputs of the multi-output light source unit are inputted into the respective cores of the multi-core optical fiber, rays of output light from the multi-core optical fiber are collectively received by the integrated light receiving device, and a plurality of outputs of the integrated light receiving device are inputted into an operational processor circuit, so that the wire gauges are verified from the light receiving position of the integrated light receiving device.

Apparatus for verifying wire gauges of multi-core optical fiber

The object of the present invention is to provide an optical pulse generator which very stably generates for a long period of time a high cycling frequency optical pulse chain. In order to obtain this object, in a ring type resonator R, the present invention provides an optical path length regulator 14 which performs high precision optical path length adjustment and an optical path length regulator 60 which performs wide range optical path length adjustment, and extracts a clock signal by converting an optical pulse emitted from the ring type resonator R to an electrical signal by a clock extractor 42, detects the frequency difference between a base frequency signal output form a synthesizer 52 by a frequency difference detector 50, and controls said optical path length regulator 14 and said optical path length regulator 60.

Optical pulse generator

According to the present invention, damage to a photo-detector disposed in clock signal extractor by means of an optical pulse having an optical power exceeding a rated value is prevented. A ring resonator generates a repetitive, high-frequency optical pulse. Optical branching circuit branches a portion of the optical pulse circulating through ring resonator, while optical branching circuit further branches a portion thereof to protective device. Pumping source generates an excitation light for exciting a rare-earth doped optical fiber. Optical multiplexer couples the optical pulse branched by optical branching circuit, and the excitation light. Upon excitation by means of the excitation light, rare-earth doped optical fiber amplifies and emits the incoming optical pulse. The optical power of the excitation light is adjusted such that the output of rare-earth doped optical fiber reaches a saturation power. Optical switch blocks the incoming optical pulse during the time period when pumping source is not emitting an excitation light, and during a fixed time period following the emission of the excitation light. In this manner, the entry of an excessively large optical pulse exceeding the saturation power into photo-detector at the time of starting up the power source is prevented. Optical attenuator attenuates the optical power of the optical pulse emitted from optical switch to an optical power which the photo-detector is capable of photo-detecting. Photo-detector converts the optical pulse emitted from protective device into an electronic signal; narrow band filter extracts a clock signal from the output of photo-detector; and electric amplifier amplifies the output of narrow band filter, and outputs a clock signal. Phase shifter adjusts the phase of this clock signal; electric amplifier amplifies the output of phase shifter, and outputs a clock signal to optical modulator. Optical modulator modulates the intensity of the light circulating through the ring resonator based on the clock signal, and generates an optical pulse.

Growing community of inventors

Kanagawa, Japan

Rikihiro Iida