Luminescence thermometry can perform noninvasive thermal sensing with high spatial resolution and fast response, emerging as an exciting field of research due to its promising applications in biomedicine. Nevertheless, because of the interaction between light and complex tissues, the reliability and the accuracy of this technique suffer serious interference, which significantly restricts its practical utilization. Here, a strategy to implement effective luminescence nanothermometry is preliminarily proposed by employing the different thermal responses between Yb3+→Nd3+ and Nd3+→Yb3+ energy transfer processes. Different from the traditional ratiometric sensing method, where two luminescence intensities are used as the thermal response parameters, we use two intensity ratios between Yb3+ and Nd3+ near-IR emissions that are obtained under dual excitation as the detecting and reference signals to perform temperature measurement. This multiparameter-based, self-reference thermometry technique, as we define it, exhibits excellent immunity to the influences arising from the fluctuation and loss of pumping sources as well as the luminescence attenuation in media. High thermal sensitivity (∼2.2%K-1) and good resolution (∼0.35°C) are successfully achieved here, accompanied by a measurement error of ∼1.1°C in a biological environment test, while large errors are observed based on the traditional ratiometric approach (∼8.9°C,∼23.2°C). We believe the viewpoint in this work could boost luminescence thermometry and provide an ingenious route toward high-performance thermal sensing for biological systems.

We experimentally demonstrate a channel-reuse bidirectional 10 Gb/s/λ long-reach dense wavelength-division multiplexing passive optical network (DWDM-PON) and an optical beat-noise-based automatic wavelength control method for a tunable laser used in a colorless optical network unit (where λ=wavelength). A 55 km, bidirectional, 400 Gb/s (40×10 Gb/s) capacity channel-reuse transmission with 100 GHz channel spacing is achieved. The transmission performance is also measured with different optical signal to Rayleigh backscattering noise ratios and different central wavelength shifts between upstream and downstream in the channel-reuse system.