Fig. 1. Double-asymmetric waveguide (black line) and simulated intensity distribution (blue line)

Fig. 2. Calculation results of far-field

Fig. 3. Relationship between (a) operation current or (b) WPE and cavity length and AR-reflectivity

Fig. 4. Power-current curves and efficiency-current curves obtained by CW. (a) 20 ℃; (b) 40 ℃

Fig. 5. Variation of slow-axis divergence angle (95% power) with CW current

Fig. 6. Power-time curves of nine devices in aging-test under the conditions of 40 ℃ and continuous current of 15 A

Fig. 7. (a) Power-QCW current curves of COS before and after 4740 hour aging-test at 30 ℃; (b) optical spectral curves of COS before and after 4740 hour aging-test at 20 A QCW current)