SOME CHARACTERISTICS OF AN EXTREMELY-SHORT-EXTERNAL-CAVITY LASER-DIODE REALIZED BY BUTT COUPLING A FABRY-PEROT LASER-DIODE TO A SINGLE-MODEOPTICAL-FIBER

When butt coupling a Fabry-Perot laser diode to an extremely closely s paced waveguide (separation less than or equal to a few times the Rayl eigh range of the laser beam), there is a trade-off between the optima l power coupling and the variation of the coupled laser diode's operat ional characteristics. Changes in the butt-coupling configuration para meters influence the coupling efficiency, as well as the strength of t he feedback into the laser diode. Using a previously reported phenomen ological model that treats the butt-coupled laser diode as an extremel y short external-cavity (ESEC) device, we quantitatively describe how the butt-coupling parameters can be used to control the output power, threshold current, wavelength, and relative intensity noise of the ESE C laser diode. Our analyses are supported by experimental results. The importance of choosing the correct coordinate plane for evaluation of the overlap integrals that are used in the model is also discussed. ( C) 1998 Optical Society of America.