Distributed feedback coupling coefficient in diode lasers with metallized gratings

First-order distributed-feedback (DFB) evanescent coupling effects are investigated in heterojunction diode laser structures with integrated, metallized diffraction gratings. A closed-form expression for the DFB coupling coefficient kappa is derived using a ray optics technique. The expression can be evaluated easily since it depends only on the laser wavelength, the grating depth, and the parameters of the metallized planar waveguide. The validity of the expression is established by using a truncated Floquet-Bloch approach to compute kappa .<
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