High-power (500 mW) narrow-linewidth (21 kHz) low-RIN (-168 dB/Hz) distributed feedback laser

A high-power, narrow-linewidth, low-relative-intensity-noise (RIN) distributed feedback (DFB) laser is demonstrated. The laser employs four strained AlGaInAs quantum wells and three diluted waveguides to reduce internal loss, and enhance heat dissipation performance to reach a high power and low noise operation. At a test temperature of 15 °C, the DFB laser with a cavity length of 1.5 mm exhibited single mode output power of 517 mW in pulsed mode and 424 mW in continuous-wave (CW) mode. with far-field full width at half maximum (FWHM) divergence angles of 10°×20°. In addition, the DFB laser achieved an intrinsic linewidth of 21 kHz, and an ultra-low RIN of less than -168 dB/Hz.