Abstract: A method to tune an emission wavelength of a wavelength tunable laser apparatus is disclosed. The laser apparatus implements, in addition to a wavelength tunable laser diode (t-LD) integrating with a semiconductor optical amplifier (SOA), a wavelength monitor including an etalon filter. The current emission wavelength is determined by a ratio of the magnitude of a filtered beam passing the etalon filter to a raw beam not passing the etalon filter. The method first sets the SOA in an absorbing mode to sense stray component disturbing the wavelength monitor, then correct the ratio of the beams by subtracting the contribution from the stray component.

Abstract: A method to tune an emission wavelength of a wavelength tunable laser apparatus is disclosed. The laser apparatus implements, in addition to a wavelength tunable laser diode (t-LD) integrating with a semiconductor optical amplifier (SOA), a wavelength monitor including an etalon filter. The current emission wavelength is determined by a ratio of the magnitude of a filtered beam passing the etalon filter to a raw beam not passing the etalon filter. The method first sets the SOA in an absorbing mode to sense stray component disturbing the wavelength monitor, then correct the ratio of the beams by subtracting the contribution from the stray component.

Abstract: A method to tune an emission wavelength of a wavelength tunable laser apparatus is disclosed. The laser apparatus implements, in addition to a wavelength tunable laser diode (t-LD) integrating with a semiconductor optical amplifier (SOA), a wavelength monitor including an etalon filter. The current emission wavelength is determined by a ratio of the magnitude of a filtered beam passing the etalon filter to a raw beam not passing the etalon filter. The method first sets the SOA in an absorbing mode to sense stray component disturbing the wavelength monitor, then correct the ratio of the beams by subtracting the contribution from the stray component.

Abstract: A method to tune an emission wavelength of a wavelength tunable laser apparatus is disclosed. The laser apparatus implements, in addition to a wavelength tunable laser diode (t-LD) integrating with a semiconductor optical amplifier (SOA), a wavelength monitor including an etalon filter. The current emission wavelength is determined by a ratio of the magnitude of a filtered beam passing the etalon filter to a raw beam not passing the etalon fitter. The method first sets the SOA in an absorbing mode to sense stray component disturbing the wavelength monitor, then correct the ratio of the beams by subtracting the contribution from the stray component.

Abstract: A semiconductor light source system includes a laser diode that is operated in a variable temperature environment and a driver circuit, wherein the driver circuit sets a magnitude of a signal current supplied to the laser diode below an upper limit level that corresponds to a maximum operational temperature of the laser diode. The driver circuit simultaneously sets a relative magnitude of the signal current with respect to a bias current such that a sufficient extinction ratio is achieved in an output optical beam and further sets a relative magnitude of the signal current with respect to the bias current such that a sufficiently small oscillation delay is achieved in the laser diode.

Abstract: A semiconductor optical source includes a first laser diode supplied with a signal current pulse and a first bias current for producing an output optical signal pulse in response to the signal current pulse, a first biasing circuit for supplying the first bias current to the first laser diode, a second laser diode supplied with a second bias current for producing an output optical beam in response thereto, a second biasing circuit for supplying the second bias current to the first laser diode; a heat sink for maintaining the first laser diode and the second laser diode at a substantially identical temperature; and a threshold detection circuit for detecting a threshold of laser oscillation of the second laser diode, wherein the threshold detection circuit controls the first biasing circuit such that the first bias current is maintained at a level that is related to the threshold of the second laser diode.

Abstract: An optical bistable laser diode includes an elongated intrinsic active semiconductor element having upper and lower surfaces and a pair of spaced ends. A semiconductor clad layer is disposed on one of the surfaces of the semiconductor element and another semiconductor clad layer of a different conduction type is disposed on the other surface of the semiconductor element. One of the semiconductor layers is coextensive in length with the semiconductor element. The diode includes a mirror at each end of the semiconductor element presenting a resonator. The diode also includes first and second electrodes on the coextensive semiconductor layer. One electrode extends along the semiconductor layer from one end thereof for a distance L.sub.1. The other electrode extends along the semiconductor layer from the other end thereof for a distance L.sub.2. The electrodes are disposed in longitudinal alignment and the same are spaced apart a distance L.sub.

Abstract: A bistable semiconductor laser device has reset light irradiation means for irradiating a reset light for stopping the delivery of a lasing light from the laser. The laser comprises an active layer comprising a gain region in which stimulated emission occurs to attain a optical gain and a saturable absorption region in which no optical gain is attained at the lasing wavelength, resetting of the laser being carried out by irradiating onto the gain region of the laser a light having a wavelength in accordance with which the irradiated light is amplified by stimulated emission thereby to reduce carriers in the gain region of the laser.