Abstract: A semiconductor laser apparatus comprises a light-emitting portion including a light-emitting device for outputting a laser beam, a light-receiving element for receiving the laser beam outputted from said light-emitting device, a wavelength monitoring portion including an optical system disposed between said light-emitting device and said light-receiving element, a control portion for controlling the wavelength of the laser beam outputted from said light-emitting device by controlling the temperature of said light-emitting device based on the wavelength of the laser beam detected by said wavelength monitoring portion, an optical isolator disposed on the optical path between said light-emitting device and said wavelength monitoring portion for preventing the light from returning from said wavelength monitoring portion back to said light-emitting device, and a temperature regulating portion for independently controlling the temperatures of said light-emitting portion and wavelength monitoring portion.

Abstract: An optical module includes a light-emitting device that outputs light, a sub-mount made of a dielectric substance having thermal conductivity on which the light-emitting device is placed, a base made of a metal on which the sub-mount is placed, a cooling device on which the base is placed and which cools heat generated by the light-emitting device, and a power supply line that is provided on the sub-mount and supplies the light-emitting device with a high-frequency modulating signal for driving the light-emitting device, where capacitances Cs and Cp of the sub-mount and the cooling device are connected in series to an equivalent circuit formed between the light-emitting device and the ground.

Abstract: The present invention provides a system for controlling a wavelength of laser light comprising: a light-emitting device for outputting laser light; means for regulating a temperature of said light-emitting device; a wavelength monitor for receiving the laser light transmitted from said light-emitting device through an optical filter, said optical filter having a periodic wavelength-transmissivity intensity curve; a controlling unit for providing a control signal to control an current supplied to said temperature regulating means responsive to a output signal from said wavelength monitor; said control signal having a polarity; and means for switching the polarity of said control signal.

Abstract: A transmitting device includes a light-emitting device for outputting a laser beam, a temperature regulator for regulating the temperature in the light-emitting device, a wavelength monitor device for receiving the laser beam from the light-emitting device after it has passed through a optical filter thermally coupled with the light-emitting device, a control unit for controlling the temperature in the temperature regulator based on the signal outputted from the wavelength monitor device such that the lasing wavelength in the laser beam outputted from the light-emitting device will be locked at a predetermined locked wavelength, a temperature-sensing unit for sensing the temperature in the optical filter, and a correcting unit for outputting a correction signal toward the control unit based on the temperature sensed by the temperature-sensing unit, the correction signal being operative to command the correction of any deviation in the locked wavelength associated with the temperature characteristic in the opt

Abstract: A system for regulating an angular orientation of an optical filter, constructed in accordance with the present invention, comprises a coupling member securely attached to the optical filter at one of ends thereof, a support member securely attached to the other end of the optical filter and rotatably supported on a base member of a holder, an angle adjustment member operatively associated with said coupling member and/or support member for rotating the optical filter about an axis of rotation on the base member so as to vary an angular orientation thereof relative to a light source, a controller for controlling the angle of rotational of said angle adjustment member and thus the angular orientation of the optical filter in such a manner as to attain a desired incident angle of the light to the optical filter.

Abstract: An optical module has a hermetically sealed package, a semiconductor laser element located within the package for outputting a laser beam, an optical fiber for receiving and externally delivering the laser beam outputted from the front end face of the semiconductor laser element, a prism for receiving a monitoring laser beam outputted from the back end face of the semiconductor laser element and for dividing the received laser beam into two laser beam components which are inclined relative to the optical axis with predetermined angles less than 90 degrees, a first photodiode for receiving one of the laser beam components divided by the prism, a second photodiode for receiving the other laser beam component from the prism, an optical filter disposed between the first photodiode and the prism and adapted to permit only a laser beam having a predetermined wavelength range to pass therethrough, and a PD carrier in which the first and second photodiodes are mounted on the same mount surface.

Abstract: A laser module in which a fiber grating fixed in a ferrule is used as a distributed reflector to stabilize the oscillation characteristic of a laser by maintaining the original reflection characteristics of the fiber grating. Only one or more portions of a fiber grating that do not include a grating, namely, a non-grating forming portion(s), are fixed to a ferrule by solder. The portion of the fiber that includes the grating, i.e., the grating forming portion, is not subject to metal deposition. Thus the deformation and/or degradation of a grating due to heat from the solder is decreased or completely avoided.

Abstract: A semiconductor laser apparatus comprises a light-emitting portion including a light-emitting device for outputting a laser beam, a light-receiving element for receiving the laser beam outputted from said light-emitting device, a wavelength monitoring portion including an optical system disposed between said light-emitting device and said light-receiving element, a control portion for controlling the wavelength of the laser beam outputted from said light-emitting device by controlling the temperature of said light-emitting device based on the wavelength of the laser beam detected by said wavelength monitoring portion, an optical isolator disposed on the optical path between said light-emitting device and said wavelength monitoring portion for preventing the light from returning from said wavelength monitoring portion back to said light-emitting device, and a temperature regulating portion for independently controlling the temperatures of said light-emitting portion and wavelength monitoring portion.

Abstract: The optical output of an optical device branched by means of an optical coupler is partially fetched by means of a wavelength stabilizer that includes an FBG section, whereby the passing wavelength characteristic of a fiber grating, which is believed originally to depend little on temperature, can be prevented from further changing. The wavelength of the optical device is tuned by means of a light wavelength tuning device that includes the wavelength stabilizer. Thus, the tuned wavelength is less liable to suffer an error that is attributable to the change of environmental temperature, so that the temperature dependence of the wavelength tuning operation is lowered.