Abstract: An optical fiber transmits signal light and the excitation light for driving an actuator each having a different wavelength to a probe. In the probe, the signal light and excitation light are separated from each other by an optical filter and the excitation light is irradiated to a photo diode. The signal light is supplied to a MEMS mirror unit. Then, the MEMS mirror unit is driven by an electromotive force obtained by the photo diode. In this manner, by modulating intensity of the excitation light, the signal light can be deflected.

Abstract: In an optical element, a first mirror stack layer is formed on a substrate, and a spacer layer made of a paraelectric material having a secondary electrooptic effect is formed thereon through a first conductive thin film. Further, a second mirror stack layer is formed thereon through a second conductive thin film, and a coupling layer is formed thereon; thus, a basic structure of the optical element is formed. By changing a voltage to be applied between the first and second conductive thin films, it becomes possible to switch wavelengths of light to be transmitted through the optical element at a high speed.

Abstract: An optical element has a structure in that a first mirror stack layer is formed on a substrate. A first transparent conductive film, a conductive buffer layer, a spacer layer having a primary or secondary electrooptic effect, a conductive buffer layer and a second transparent conductive film are stacked thereon in succession; and a second mirror stack layer is further formed thereon. A voltage is applied between the first and second transparent conductive films. The applied voltage change the refractive index of the spacer, changes a wavelength to be transmitted through or reflected from the layer.

Abstract: Two set of filter chips on the upper and lower surfaces, each of which has a wavelength characteristic corresponding to each wavelength component of wavelength-multiplexed light, are mounted on a transparent substrate to make an optical filter element. When the wavelength-multiplexed light is inputted to the optical filter element via an optical fiber and when the same light components as those having the wavelengths demultiplexed by an optical fiber is also inputted, the demultiplexed light and the replaced wavelength-multiplexed light will be obtained at another optical fibers, respectively.

Abstract: A gain medium 12 and a tunable filter are provided in an optical path of laser oscillation. The tunable filter has an optical beam deflector for periodically changing an optical beam at a constant angular speed, a prism 26 on which deflected light is made incident, and a diffraction grating 27. Appropriate selection of the apex angle ? of the prism 26 and an angle ? formed by the prism 26 and the diffraction grating 27 can provide a tunable laser light source for changing the oscillation frequency at high speed and a constant variation rate.

Abstract: Filter chips, each of which has a wavelength characteristic corresponding to each wavelength component of wavelength-multiplexed light, are mounted on a transparent substrate to make an optical filter element. When wavelength-multiplexed light is input to the optical filter element via an optical fiber, the transmission and reflection characteristics vary depending upon which filter chip the light enters. The input position of the light to the optical filter element is changed by moving it in a direction that the filter chips are arranged, so that different selection characteristics can be obtained.

Abstract: In order to realize an optical attenuator which has an attenuation factor independent of the wavelength of incident light, a glass substrate is used in an attenuator plate, and the glass substrate is formed in a tapered section so that its incident and exit planes may not be parallel to each other. On one side thereof, a metal film corresponding to the attenuation factor is formed. Also one side of the glass substrate is covered with an antireflection coating for canceling the wavelength dependence of the metal film. Thereby ripple of attenuation factor due to wavelength can be eliminated, and the wavelength dependence may be minimized.

Abstract: In order to realize an optical attenuator which has an attenuation factor independent of the wavelength of incident light, a glass substrate is used in an attenuator plate, and the glass substrate is formed in a tapered section so that its incident and exit planes may not be parallel to each other. On one side thereof, a metal film corresponding to the attenuation factor is formed. Also one side of the glass substrate is covered with an antireflection coating for canceling the wavelength dependence of the metal film. Thereby ripple of attenuation factor due to wavelength can be eliminated, and the wavelength dependence may be minimized.

Abstract: In order to realize an optical attenuator which has an attenuation factor independent of the wavelength of incident light, a glass substrate is used in an attenuator plate, and the glass substrate is formed in a tapered section so that its incident and exit planes may not be parallel to each other. On one side thereof, a metal film corresponding to the attenuation factor is formed. Also one side of the glass substrate is covered with an antireflection coating for canceling the wavelength dependence of the metal film. Thereby ripple of attenuation factor due to wavelength can be eliminated, and the wavelength dependence may be minimized.

Abstract: The light emitted by a laser diode 1 is entered into a beam splitter 5, and its reflected light is given to an optical band pass filter 8. The light passing through the optical band pass filter 8 is received by a photo diode PD1.The light once reflected by the optical band filter 8 and passing through the beam splitter 5 is received by a photo diode PD2. The reception ratio of the photo diodes PD1, PD2 is calculated in output ratio calculator 9. By controlling the emission wavelength of the laser diode 1 so that its ratio may be constant, laser light of high precision and stable wavelength is emitted.

Abstract: A wavelength locker 4 is provided at one light beam exit end of a laser diode 1. The wavelength locker 4 incorporates an interference optical filter 3, and photo diodes PD1, PD2 for detecting its transmitted light and reflected light. A thermistor 15 and a temperature detector 14 for detecting the temperature of the interference optical filter 3 are provided. Calculating the output ratio of the photo diodes PD1, PD2, the wavelength is controlled so that the correction value by the temperature of the output ratio may be a specified value. The laser diode 1 and wavelength locker 4 are sealed in an optical module 11, and mounted on a substrate together with other blocks. Thus is obtained a laser light source apparatus composed in a simple and small constitution within a emission possible wavelength range of laser light source and capable of emitting stably.

Abstract: The light emitted by the laser diode 1 is put into an interference optical filter 5. The light passing through the interference optical filter 5 and the reflected light are respectively received in photo diodes PD1, PD2. Their output ratio is calculated by an adder 13, a subtracter 14, and a divider 15, and a wavelength signal is obtained. The difference of the output ratio and reference value is detected as error signal by an error detector 16, and the emission wavelength of the laser diode 1 is controlled so that the error signal may be zero.