Wavelength-Selective Optical Amplifier Based on Microfiber Coil Resonators

In this paper, we present a new and compact structure for optical amplifiers based on erbium-doped microfiber coil resonators (MCR). The performance of the device is modeled by solving numerically the MCR coupled-mode equations and the rate equations in the steady-state regime. Characteristics of amplifier are analyzed for two-, three-, and four-turn MCRs. The signal gain spectrum is studied in terms of amplifier length, signal wavelength, and signal, and pump power. Simulation results demonstrate that such a device selectively amplifies specific wavelengths due to its resonance nature. It is possible to obtain optical gain as high as 30 dB using a 10 mW pump power and a 0.1 μW signal power. The amplified peaks show very narrow full-width at half-maximum that are very promising for microlasers.