Optical channel dropping using dielectric microspheres

Abstract

Dielectric microspheres, with their morphology dependent resonances, are used to resonantly couple light from half optical fiber couplers. The dropped channels are observed in the elastic scattering and the transmission spectra. The excitation of the microsphere with the nearly Gaussian beam in the half optical fiber coupler provides spatially and spectrally selective, and enhanced light coupling. The filter drops approximately 10% (0.5 dB) of the power at the resonance wavelength. A tunable single mode distributed feedback diode laser is used as the infrared excitation source. The generalized Lorenz-Mie theory, describing the illumination of the microsphere with a Gaussian beam, is used to interpret the experimental results.