Amplified Spontaneous Emission from Optical Fibers Containing Anisotropic Morphology CdSe/CdS Quantum Dots Under Continuous Wave Excitation

Abstract

Fiber laser field is typically dominated by rare earth ions as gain material in the core of a silica optical waveguide. Due to their specific emission wavelengths, rare‐earth‐doped fiber lasers are available only at few predefined wavelengths. However, quantum dots (QDs) are materials which show tunable emission with change in size and composition. Due to such tunability, QDs seem to be promising candidates for obtaining fiber lasers at a spectrum of wavelengths which is not possible using rare earth ions. To replace rare earth ions with QDs, it is of paramount importance that QDs show signatures of optical gain. Herein, the synthesis of asymmetric pod‐shaped CdSe/CdS QDs is reported, which demonstrate efficient gain on pumping. The intrinsic gain properties of the QDs are evaluated through transient absorption (TA) spectroscopy. Later, the exquisite QDs are used to fabricate specialty fibers from which amplified spontaneous emission (ASE) is obtained using continuous wave laser pump at room temperature. Finally, emission signal stability is checked by studying photobleaching and controlling the concentration of the QDs.

Keywords

• amplified stimulated emission
• fiber lasers
• optical gain
• quantum dots