Intensity dynamics in a waveguide array laser

• Published in: Optics communications Vol. 284; no. 4; pp. 971 - 978
• Main Authors: Feng, Mingming, Williams, Matthew O., Kutz, J. Nathan, Silverman, Kevin L., Mirin, Richard P., Cundiff, Steven T.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2011
• Subjects: 2010 MSC; 78A60; Arrays; Dynamics; Injection current; Mathematical models; Nonuniform; Oscillations; Phase shift; Tuning; Waveguides; 2010 MSC; 78A60
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2010.10.041

We consider experimentally and theoretically the optical field dynamics of a five-emitter laser array subject to a ramped injection current. We have achieved experimentally an array that produces a robust oscillatory power output with a nearly constant π phase shift between the oscillations from each waveguide. The output power also decreases linearly as a function of waveguide number. Those behaviors persisted for pump currents varying between 380 and 500 mA with only a slight change in phase. Of note is the fact that the fundamental frequency of oscillation increases with injection current, and higher harmonics are produced above a threshold current of approximately 380 mA. Experimental observations and theoretical predictions are in agreement. A low dimensional model was also developed and the impact of the nonuniform injection current studied. A nonuniform injection current is capable of shifting the bifurcations of the waveguide array providing a valuable method of array tuning without additional gain or structural alterations to the array. ►Five-emitter array fabricated with a sloped injection current. ►Array produces oscillatory power output between 380 and 500 mA. ►Frequency of power oscillation is directly related to injection current. ►Good agreement between experiment and the theoretical model. ►Injection current slope alters the gain at where the array loses stability.