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The surface of epilayers grown by chemical vapor deposition (CVD) cannot be characterized insitu by RHEED, LEED, or Auger spectroscopy methods used for molecular beam epitaxy. But, unlike the epilayers grown by molecular beam epitaxy, those grown by CVD method have their crystallographic and electric properties controlled by the characteristics of a 4–20-μm-thick motionless gas layer called boundary layer. Samples of the boundary layer can be probed as a function of the distance above the growth surface and analyzed by gas phase chromatography in the case of silicon epitaxy in order to measure concentration and concentration gradient of pertinent chemical species close to the growth surface. This analysis allows us to explain the behavior of the growth rate, the kinetics of the incorporation of impurities and the crystallographic quality of eqilayers as a function of the growth parameters. General results can be used to explain most cold wall reactor behavior. GaAs and InP materials grown by the organometallic method are treated as examples.

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Low levels of intensity noise in semiconductor lasers is a key feature for numerous applications such as high resolution spectroscopy, fiber-optic sensors, signal distribution in broadband analog communications as CATV, and more generally for microwave photonics systems. In particular, a DFB laser with very low relative intensity noise (RIN) levels from 0.1 to 20 GHz is a key component as it correspond to the whole frequency bandwidth of interest for radars. Several approaches have been reported but most suffer from the compromise between RIN level and power out level and stability, with RIN level in the range -150 dB.Hz -1 to -155 dB.Hz -1 in this frequency range [1,2]. We report here results from a new AlGaInAs DFB laser developed at 3S PHOTONICS. Excellent device performance is observed across an operating range from the laser threshold up to the thermal roll-over. Pure longitudinal single mode at 1545 nm is obtained over the whole current operating range with side mode suppression ratio higher than 50dB. The maximum output power reaches up to 130 mW. In these conditions, RIN levels below -160 dB.Hz -1 is obtained in up to 20 GHz. These are the best results to our knowledge combining such high single mode output power with such low RIN level in the frequency range 0.4-20 GHz.

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