Abstract: A laser light source includes: a resonance unit with a light emitter; and an optical negative feedback unit. The resonance unit includes: a first waveguide; a first reflector to input the reflected light to the first waveguide; a second waveguide; a second reflector connected to the second waveguide; and a ring resonator between the first waveguide and the second waveguide. The light from the first reflector is blocked from the ring resonator and partially transmitted to a first end of the first waveguide opposite to a second end connected to the light emitter and the first reflector. The optical negative feedback unit includes: a third waveguide to which the light transmitted to the first end of the first waveguide is inputted; and a third reflector connected to the third waveguide. The light from the third reflector is inputted to the first waveguide via the third waveguide.

Abstract: A laser apparatus includes: a light source configured to generate laser light; and an optical negative feedback unit configured to narrow a spectral line of the laser light using optical negative feedback. A modulation signal is input to the light source to modulate a frequency of the laser light. A modulation amount in the frequency of the laser light is detected. A modulation sensitivity is calculated from (i) the modulation amount and (ii) an intensity of the modulation signal.

Abstract: A laser apparatus includes: a light source configured to generate laser light; and an optical negative feedback unit configured to narrow a spectral line of the laser light using optical negative feedback. A modulation signal is input to the light source to modulate a frequency of the laser light. A modulation amount in the frequency of the laser light is detected. A modulation sensitivity is calculated from (i) the modulation amount and (ii) an intensity of the modulation signal.

Abstract: A laser light source includes: a resonance unit with a light emitter; and an optical negative feedback unit. The resonance unit includes: a first waveguide; a first reflector to input the reflected light to the first waveguide; a second waveguide; a second reflector connected to the second waveguide; and a ring resonator between the first waveguide and the second waveguide. The light from the first reflector is blocked from the ring resonator and partially transmitted to a first end of the first waveguide opposite to a second end connected to the light emitter and the first reflector. The optical negative feedback unit includes: a third waveguide to which the light transmitted to the first end of the first waveguide is inputted; and a third reflector connected to the third waveguide. The light from the third reflector is inputted to the first waveguide via the third waveguide.

Abstract: The present invention is to provide a wavelength tunable DBR laser having the wider wavelength tuning characteristic, able to attain a 6 nm or more continuous wavelength shift and also higher in output power than a conventional wavelength tunable DBR laser. The DBR laser is constituted such that optical waveguides formed on a substrate, comprising an active region optical waveguide 22 having a light emitting function and passive region optical waveguides 23a and 23b provided on both ends of the active region 22, these passive region optical waveguides 23a and 23b have anterior and posterior DBR regions 24 and 29 with a wavelength tuning function, a posterior DBR region 29 is provided with a diffraction grating whose length is 95% or more in a saturated effective length value, and an anterior DBR region 24 whose length is shorter than the above length to take out the emitting light.

Abstract: A wide band distributed Bragg reflector having a reflectivity extremely greater than that of a narrow band distributed Bragg reflector mirror portion on the output side of a bistable type wavelength conversion device is arranged on the incident side. The input light in TM polarization mode is used as an input signal light and the wavelength conversion is performed by tuning the narrow band distributed Bragg reflection mirror portion on the output side from which an output light in TE polarization mode outgoes perpendicularly to the input light. The input signal light and the output signal light are polarized in such a manner that they are perpendicular to one another and, therefore, the device can be realized as a one-directional device. The use of any isolator is not required.

Abstract: A method of stabilizing the frequency of a semiconductor laser comprises stabilizing a time-dependent frequency fluctuation by utilizing an optical energy absorption medium including an isotope acetylene gas molecule. An apparatus for stabilizing the frequency of a semiconductor laser, comprises a semiconductor laser, an optical energy absorption medium, a photodetector and a control circuit as essential elements. The optical energy absorption medium includes an isotope acetylene molecule.