Nonlinear optical input-output characteristics of 1.55 μm injection-locked vertical-cavity surface-emitting lasers

The optical input-output characteristics of a 1.55 mum vertical-cavity surface-emitting laser (VCSEL) with external light injection to its fundamental mode were investigated. Appropriate wavelength detuning of external light enables abrupt modal switching in an injection-locked VCSEL. We found that the obtained nonlinear transfer function is strongly dependent on the distance between a VCSEL and an input lensed fiber. As the distance was changed, different optical input-output characteristics were observed, demonstrating that such a VCSEL can be employed in various optical signal-processing schemes, for example as an optical regenerator or an optical inverter. (C) 2004 American Institute of Physics.