Phase-locked laser array far-field normalization

The normalization of the far-field distribution from phase-locked linear arrays of evanescently coupled semiconductor diode lasers is evaluated. As the element number N to infinity , the peak irradiance of the fundamental array mode tends to 81% of the peak irradiance of an array of in-phase equal-intensity diodes. It is also found that for N>or=10, the peak irradiance is proportional to 0.81 (1+1/N)N/sup 2/, and the diffraction-limited beamwidth is approximately 1.19 lambda (N+1)S where lambda is the vacuum wavelength and S is the array period. The far-field array factor is the same for an N-element array and an (N+1) S-wide cosine source as long as N>or=10.<
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