Microsphere-based channel dropping filter with an integrated photodetector

Morphology-dependent resonances of dielectric microspheres are used for polarization-insensitive optical channel dropping from an optical fiber half coupler to a silicon photodetector in the M-band. The dropped channels are observed both in the elastic scattering and the transmission spectra. The highest quality factor morphology-dependent resonances have repetitive channel separations of 0.14 nm and linewidths of 0.06 nm. The filter drops approximately 10% (0.5 dB) of the power at the resonance wavelength. The power detected by the photodiode is estimated to be 3.5% of the power in the fiber.