The linewidth of a room-temperature free-running 940-nm cw single-frequency 1-mm-long quantum-well InGaAs/AlGaAs diode laser in a 10-cm-long external cavity has been measured as a function of the output power by the heterodyne technique. The power-dependent component of the observed Lorentzian linewidth displays a linewidth–power product of 28 ± 4 kHz mW, which is 2 orders of magnitude larger than that predicted from the spontaneous emission model. The shot-noise model of Welford and Mooradian [Appl. Phys. Lett. 40, 560 (1982)] for the power-independent linewidth has been extended to account for the observed power-dependent linewidth.
© 1995 Optical Society of America
Original Manuscript: May 5, 1995
Published: September 1, 1995
L. Hsu, A. Mooradian, and R. L. Aggarwal, "Spectral linewidth of a free-running continuous-wave single-frequency external-cavity quantum-well InGaAs/AlGaAs diode laser," Opt. Lett. 20, 1788-1790 (1995)