Near-field and far-field patterns of phase-locked semiconductor laser arrays

Abstract

A gain-guided phase-locked semiconductor laser array has been observed to emit a single narrow lobed far-field radiation pattern up to 70 mW, at which power level it exhibits a distinct change. We show that this effect results from a new phase-locked mode attaining threshold; the original mode remains phase locked above this power level.

Spectrally Resolved Near-Field Intensity Measurements from Gain-Guided Twin-Stripe Laser Diode Arrays

“…The far-field pattern appears to be dominated by the centered self- The simultaneous operation of two spectrally separated near-field intensity distributions has also been reported in a phase-locked filament laser 2 4 and in a gain-guided ten-stripe array. 25 The spectrally resolved near-field measurements on the gain-guided tenstripe array reported 2 5 the onset, at higher pump levels, of a near-field intensity distribution positioned between the stripes in conjunction with the distribution positioned under the stripes. The spectral separation of these modes was reported to be 4 A.…”

Modal analysis of semiconductor lasers with nonplanar mirrors

“…This assumption is tantamount to assuming that all of the longitudinal modes of the resonator are degenerate. The second and third terms are common to all elements of BL and may be pulled out as a scalar times the identity f. The result is that the propagation matrix can be written as -With this substitution, (5) can be written as…”

“…One has been to fabricate phase-locked arrays of lasers which are individually too narrow for filamentation to appear [ 2 ] . Such lasers have produced the highest CW power reported to date [3]; however, their design remains plagued by problems of incomplete phase-locking [4] and the appearance of an antisymmetric far field [5].…”

“…The eigenmodes of the resonator are found by requiring that the lasing field reproduce itself after one roundtrip, i.e., that (5) This is, in general, a nonlinear eigenvalue problem. The free parameters…”