DBR laser with nondynamic plasma grating formed by focused ion beam implanted dopants

A static plasma grating has been demonstrated experimentally (see M.C. Wu et al., Appl. Phys. Lett., vol.53, no.4, p.265-7, 1988) in a large-optical-cavity focused-ion-beam-distributed-Bragg-reflector (FIB-DBR) GaAlAs/GaAs laser diode. The grating is formed by implanting stripes of dopants with a focused ion beam. The dopants ionize to form periodic fluctuations in the carrier concentration which, through the Kramers-Kronig relations, form an index grating. A model of the grating strength for optimization of the laser design is developed and presented. The computed results show that the coupling coefficient k can be increased by more than an order of magnitude over the 15 cm/sup 1/ experimentally. Therefore, FIB-DBR (or FIB-distributed-feedback (DFB)) lasers with performance comparable to that of conventional DBR (or DFB) lasers can be expected.<
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