Abstract:We propose and demonstrate a passively mode-locked Erbium-doped fiber laser based on symmetrical nonlinear optical loop mirror. The nonlinear optical loop mirror with intensitydepended transmission can act as an equivalent saturable absorber, which results in passively mode-locking of fiber laser. Pulse trains with fundamental cavity frequency and its various harmonic frequencies have been obtained.

With the simple ABC model, we demonstrated that the internal quantum efficiency (IQE) of InGaN light-emitting diodes (LEDs) at lower temperature must be higher than that at higher temperature without carrier leakage; this is contradicted by the experimental results of blue InGaN/GaN single-quantum-well (SQW) LEDs. Combined with the variations of IQE and dominant wavelength of SQW LEDs with forward current density, we believe that the electrons will overflow from the well easily after filling up in a higher state, and electron leakage is the main factor for efficiency droop.

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The development of blue thermally activated delayed fluorescence (TADF) emitters that can simultaneously achieve narrowband emission, high efficiency, and low efficiency roll-off in organic light-emitting diodes (OLEDs) remains a significant...