Controlled Modification and Direct Characterization of Multimode-Fiber Refractive-Index Profiles

We present a new infrared (IR) detection scheme based on the infrared quantum counter (IRQC) detector and utilizing the photon avalanche process. At the time of its discovery, the phenomenon of photon avalanche was considered a limitation rather than an advantage for the development of IRQC. Both the experimental results and the numerical modeling presented demonstrate that the process responsible for photon avalanche can be used to enhance the detection of an IR signal. A new room-temperature IR detection scheme is proposed on the basis of the results of this research. The novel detection scheme presented demonstrates an increase in detectivity and a decrease in the noise-equivalent power when compared with the IRQC schemes previously discussed in the literature. [Optical Society of America ]