Microrod resonator laser with versatile pumping configurations

A new Yb3+-doped silica WGM microrod resonator laser is demonstrated using different pump-delivery and signal-collection configurations, which include evanescently-coupled microtapers or direct side-pumping

Optical microstub resonator lasers

We describe the fabrication and optical performance of a new passive and active optical microstub resonator (MSR). The technique is extremely simple and enables the fabrication of high quality resonators. They are primarily cylindrical cavities (“stubs”) 10's of microns long spliced to two fiber stems of smaller diameter on either side. The splicing makes the edges of the “stub” rounded and smooth, improving the optical performance. The fabricated MSRs had typical stem/cavity diameters of 125µm/200µm, respectively, and 50-200µm lengths. Strong resonances with coupling efficiencies and Q factors > 15dB and 106, respectively, were demonstrated.Using a special Ytterbium doped fiber with doped core diameter of 220µm and cladding diameter of 240µm, we formed active MSRs with 50-500µm lengths and 125µm stem diameters. The active MSRs were side pumped by 980nm single-mode diodes through their stems. Residual pump and generated signal were monitored at the opposite fiber stem end. Strong lasing peaks in the 1060nm wavelength range were observed. No transversely scattered signal/pump light was detected. This indicates that the whispering-gallery modes were formed at the inner doped core/cladding interface. In stark contrast with previous microlaser demonstrations, this laser does not need additional microtapers/waveguides for launching or collecting light. This is the first demonstration of a robust, fully integrated, stand-alone microresonator laser where pump launching and signal collection is achieved by the fiber stems, used to form the microcavity. This is a major advancement and will impact significantly the development of future advanced sensor applications