<p>This study systematically investigates the spontaneous emission spectra of GaAs_1-xBi_x/GaAs double quantum wells (DQWs) through an eight-band <b>k</b>•<b>p</b> model, elucidating the dependence of the emission characteristics across varying well widths, barrier thicknesses, Bi compositions, doping densities, and temperatures. The emission peak intensity decreases and redshifts with increasing well-width due to weakened quantum confinement, with DQWs showing a more gradual intensity decay than SQWs. The GaAs barrier thickness of the DQWs is found to affect minimally the spontaneous emission spectra, but a GaAs_0.95Bi_0.05/GaAs DQW, where the interwell barrier is a GaAs_0.99Bi_0.01 barrier layer, demonstrates the tunability of the emission intensity with varying barrier thickness. Varying the Bi composition in the GaAs_1-xBi_x wells of the DQWs shows invariant peak intensity across low compositions (0.01–0.05) and a pronounced redshift over 30&#xa0;meV. On the other hand, simultaneous variation of Bi compositions in both wells enables a monotonic redshift. This shows a method to realize a broadband frequency tunability. A thicker interwell GaAs_1-xBi_x barrier layer, for a specified Bi composition, can result in a relatively larger redshift. Increased carrier density boosts peak intensity. As the temperature increases, the peak intensity decreases, and the peak position undergoes a redshift. Notably, DQWs exhibit slower decay rates at high energies compared to SQWs. Furthermore, under equivalent confinement conditions, DQWs demonstrate superior emission rates relative to SQWs.</p>