Microwave Direct Frequency Modulation of Cleaved-Coupled-Cavity InGaAsP Channeled Substrate Lasers

Abstract

It is well known that directly modulated semiconductor lasers exhibit changes in oscillation frequency due to variations in the refractive index and cavity temperature [1]. Frequency modulation (FM) and frequency shift keying (FSK) are potentially useful in coherent lightwave communications but pulse spreading resulting from fiber dispersion associated with undesired FM can seriously degrade the performance of high-speed long-haul intensity modulation systems.