Fujitsu Optical Components Limited

Takeyasu Tomioka

Shuichi Yasuda

Masayuki Kurisu

An optical transmitter includes an optical modulator, a tunable optical filter, a temperature sensor, and a processor. The tunable optical filter is provided on an output side of the optical modulator and transmits light of a frequency corresponding to a control voltage. The temperature sensor detects a temperature around the tunable optical filter. The processor detects an optical loss occurring in the tunable optical filter, calculates a width of a range of the control voltage in which the detected optical loss is smaller than a specified threshold, adjusts the control voltage based on the temperature detected by the temperature sensor, and shifts the control voltage by a specified amount that is larger than zero and smaller than or equal to a half of the calculated width of the range when the optical loss is larger than or equal to the threshold.

Optical transmitter and control method of tunable optical filter

An optical transmission device includes: a first drive unit that drives a VOA adjusting an attenuation amount for an optical signal from an optical amplifier; a second drive unit that drives an excitation light source of the optical amplifier; a first FF control unit that sets a first set value for the first drive unit and performs FF control; a second FF control unit that sets a second set value for the second drive unit and performs the FF control; a first control unit that controls the second drive unit in a manner that causes an optical output power from the optical amplifier to attain a first control target value; and a switch unit that switches to the first control unit when the optical output power corresponding to the second set value is attained as a result of FF control of the second FF control unit.

Optical transmission device and method for controlling optical transmission device

A coherent optical receiver includes: an attenuator that adjusts a power of an input optical signal; a mixer that mixes an optical signal output from the attenuator and local oscillator light; a photo detector that converts an optical signal output from the mixer into an electric signal; an amplifier that amplifies an output signal of the photo detector; a gain controller that controls a gain of the amplifier; a memory that stores dependence information that indicates a relation between an input optical power of an optical signal of a specified wavelength and a gain of the amplifier; and a controller that calculates an input optical power of the target wavelength based on a gain of the amplifier and the dependence information, and controls an attenuation amount of the attenuator based on the calculated input optical power, when a WDM optical signal is input into the coherent optical receiver.

Growing community of inventors

Sapporo, Japan

Takeyasu Tomioka