The Furukawa Electric Co., Ltd.

Yuji Hiratani

Tatsuhiko Ueki

Mamoru Shimada

Hiroyuki Kobayashi

Tatsuya Kimoto

Takehiko Nomura

Hideyuki Nasu

Michinori Irikawa

Toshikazu Mukaihara

Kazuaki Nishikata

An optical module including a temperature measurement module and an optical part having a temperature dependency. The module includes a temperature control part mounted directly or indirectly on the optical part and the temperature measurement part for controlling a temperature of the optical part and the measurement part by thermal contact. An adjustment system is also provided for adjusting a difference of the temperature of the optical part and the measurement part by controlling the heat flow into/out of the optical part or the measurement part.

Optical transmission module with temperature control

A temperature adjustment device has a first thermoelectric cooling module, a second thermoelectric cooling module on which the first thermoelectric cooling module is provided, and a heat generating element which is provided on the first thermoelectric cooling module and a temperature thereof is adjusted, where assuming that a substrate area of the first thermoelectric cooling module on which the heat generating element is provided is S(mm) and that an amount of generated heat of the heat generating element is Qd(mW), the relationship of 20&#x2266;Qd/S&#x2266;200 is met.

Temperature adjustment device and laser module

An optical filter is provided on a first thermo-module whose temperature is controlled to be constant, via a base. Accordingly, a wavelength discrimination characteristic of the optical filter and an optical isolator can be stabilized, thereby realizing more accurate wavelength locking. Further, a second thermo-module is provided on the first thermo-module whose temperature is controlled to be constant. Accordingly, the temperature control range of the second thermo-module can be expanded, and hence the wavelength variable range of a semiconductor laser device provided on the second thermo-module via a base and a submount can be expanded.

Laser module

There is provide a method of manufacturing a compound semiconductor (MBE) that can make the substrate surface of the semiconductor highly clean and plane so that no impurity may be left between the substrate surface and the grown crystal layer. In the step of cleaning a substrate with MBE, the substrate surface is irradiated with V molecular beams that cannot be significantly deposited out of molecular beams to be used for the crystal growth step, said V molecular beams being irradiated under a condition of P.sub.1 .ltoreq.(P.sub.2 .times.1/2), where P.sub.1 is the pressure of V molecular beams and P.sub.2 is the pressure of molecular beams in the crystal growth step and the temperature of the substrate surface is raised by heating until stabilized group III surfaces appear on the substrate surface. A very cleanand smooth substrate surface can be obtained with such an arrangement. Harmful impurities can be completely eliminated from the interface of the substrate and the crystal. The formation of a buffer layer can be effectively prevented in the initial stages of crystal growth. In short, high-quality compound semiconductors can be produced on a reliable basis.

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Tokyo, Japan

Yuji Hiratani