Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Department of Engineering Physics

First Advisor

Won B. Roh, PhD


Four-wave mixing (FWM), a nonlinear optical process, was investigated in resonant cavity light emitting diodes (RCLEDs) and vertical cavity surface emitting lasers (VCSELs) below lasing threshold. These semiconductor photonic devices consisted of an optical gain region of quantum wells sandwiched between two distributed Bragg reflector (DBR) mirrors. Pump and probe lasers were injected into the devices to generate FWM. The dependence of FWM on bias current, pump laser power, and spectral and spatial separation between pump and probe lasers was investigated experimentally. A computer model of FWM based on the wave and carrier density equations was developed and agreed well with experimental results. Conjugate reflectivities of I were obtained in the VCSEL when bias current was below threshold but above transparency. Reasonable conjugate reflectivities were obtained for pump-probe detunings up to 2 GHz in both devices. Noncollinear FWM was performed for the first time in VCSELs or RCLEDs at angles up to 10°. Both experiment and model showed the possibility of generating a strong reflected conjugate signal while minimizing the reflected pump signal. The noncollinear FWM demonstrated the possibility of phase front conjugation for correcting aberrated signals in vertical cavity devices.

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