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• A broadband dual-parameter sensor is proposed and demonstrated. • The sensor cascaded gold film and silver film, which made the range of parameters to be measured larger. • The two detection channels are independent of each other and do not affect each other. • The sensor is simple in structure and easy to prepare. Dual-parameter sensor has relatively small detection range because of restriction on resonance wavelength range. To overcome this problem, we propose a cascaded gold and silver SPR dual-parameter sensor. As the resonance wavelength ranges of gold and silver are different, cascading the two metals to make one sensor broadens the resonance wavelength range, thus increasing the sensor's detection range. The sensor uses no-core fiber as the probe and multimode fiber (MMF) as the input (output) coupler, which constitutes an MMF-NCF-MMF sensing structure. By using Magnetron sputtering, gold and silver are deposited on the outer surface of NCF. The effects of coating time and NCF length on the sensing performance were experimentally investigated to determine the optimal coating time and NCF length. The experimental results shows that the two channels of the sensor are independent of each other without crosstalk and have an extensive range of parameters to be measured. The maximum sensitivity is 3231 nm/RIU in the RI range of 1.333–1.385. It has a maximum temperature sensitivity of 6.68 nm/°C from 0 to 80 °C. In addition, the sensor has good stability and repeatability. The proposed sensor has a simple and integrated structure and is suitable for applications requiring large detection range sensing. [ABSTRACT FROM AUTHOR]

• A compact dual-channel sensor is proposed and demonstrated. • The sensor can detect temperature and refractive index simultaneously. • The two detection channels are independent and do not interfere with each other. • The sensor structure is simple and easy to prepare. To improve the integration of sensors and meet the trend of miniaturization of devices, we propose and demonstrate a compact dual-channel surface plasmon resonance (SPR) fiber sensor for detecting refractive index (RI) and temperature. In this sensor, we chose the simplest structure of optical fiber: no-core fiber (NCF), as the sensing probe. Then the silver film was deposited on the NCF surface using magnetron sputtering to excite the SPR effect. Two sensing channels were constructed on the NCF, one channel deposited with silver film for RI detection, and another channel deposited with PDMS and silver film for temperature detection. Such a construction makes the sensor compact and small. The performance of the proposed sensor is studied theoretically and experimentally. The experiment shows that the maximum sensitivity of the sensor is 3039 nm/RIU and 3.53 nm/°C when the RI ranges from 1.333 to 1.375 and the temperature ranges from 0 °C to 70 °C, respectively. The significant advantage of our proposed sensor is its simple, compact, and easy-to-prepare structure, which opens up a new direction for device miniaturization. [ABSTRACT FROM AUTHOR]

• This work utilizes TiO 2 film to tune the sensing bandwidth and the resonance wavelength range to the near-infrared band. • A dual-channel sensor with wide bandwidth is proposed. • The experimental results show that the RI range of the sensor is 1.333–1.385, and the temperature range is 10–80 ℃. • The sensor has simple structure and good repeatability. Facing the diversity and complexity of the types of parameters to be measured, multi-channel surface plasmon resonance (SPR) fiber sensors provide an excellent solution. However, the sensing bandwidth is a key factor affecting the sensor performance. In this paper, we explore a method to modulate the sensing bandwidth using the TiO 2 film. A dual-channel SPR sensor with a wide sensing bandwidth is proposed. In this sensor, no-core fiber (NCF) is used as the sensing probe, and multimode fibers are used for the transmission of optical signals. The sensor has a cascaded composite film structure, the region coated with Ag film as the refractive index sensing region and the region coated with Ag/TiO 2 /PDMS as the temperature sensing region. The experimental results show that the sensing bandwidth of the sensor varies for different TiO 2 coating times. It indicates that the TiO 2 film can regulate the sensing bandwidth flexibly. Therefore, to achieve the optimal sensing effect, the TiO 2 coating time can be flexibly adjusted according to the RI characteristics of the environment. The maximum sensitivity of this dual-channel sensor is 4.5 nm/°C and 3151 nm/RU when the temperature range is between 10 and 80 °C and the RI range is between 1.333 and 1.385, respectively. In addition, we discuss the repeatability and stability of this dual-channel sensor. [ABSTRACT FROM AUTHOR]