The Furukawa Electric Co., Ltd.

Kumiko Imai

Takehiko Nomura

Hideyuki Nasu

An optical module according to the present invention includes: a light-emitting device that outputs laser light; a temperature adjustment unit that adjusts a wavelength of the laser light outputted from the light-emitting device so as to be locked at a predetermined wavelength; a wavelength monitor unit that receives laser light outputted from the light-emitting device by allowing the laser light to pass through an optical filter provided above the temperature adjustment unit and monitors the wavelength thereof; a package for sealing the light-emitting device, the temperature adjustment unit, and the wavelength monitor unit into the inside thereof; and a package temperature detection unit for detecting a temperature of the package, in which the temperature adjustment unit adjusts an oscillation wavelength of the laser light outputted from the light-emitting device to the predetermined lock wavelength based on a signal outputted from the wavelength monitor unit, and a signal from the package temperature detection unit is used to correct the lock wavelength shift caused by temperature characteristics of the optical filter by estimating the optical filter temperature based on the detected package temperature.

Optical module, optical transmission apparatus, WDM optical transmission device, and method for stabilizing laser wavelength

A method of manufacturing a bismuth oxide superconductor, wherein a molded body of a bismuth oxide superconducting substance comprising bismuth, an alkaline earth metal, copper, and oxygen or a precursor thereof is subjected to a heat treatment for producing a superconducting phase and then subjected to one step selected from (1) a step of cooling the heated body from 700.degree. C. to 200.degree. C. in an atmosphere having an oxygen partial pressure of not less than 0.1 atm at a cooling rate of not less than 10.degree. C./min, (2) a step of cooling the heated body from 700.degree. C. in an atmosphere having an oxygen partial pressure of less than 0.1 atm at a cooling rate of less than 10.degree. C./min, and (3) a step of cooling the heated body, and then performing a heat treatment for the cooled heated body in an atmosphere having an oxygen partial pressure of not more than 0.1 atm at a temperature from 700.degree. C. to 200.degree. C.

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Tokyo, Japan

Kumiko Imai