Rui Wu

Tunable and Selectable Multipassband Microwave Photonic Filter Utilizing Reflective and Cascaded Fiber Mach–Zehnder Interferometers

In this paper, we have proposed and experimentally demonstrated a new approach to implement microwave photonic filter with tunable and selectable multiple passbands by using reflective and cascaded fiber Mach–Zehnder interferometers and dispersive medium. By employing the proposed structure, microwave photonic filter (MPF) with more aperiodic passbands compared with previous methods have been achieved. The proposed MPF exhibits advantages such as simple structure, easy implementation, good tunability, and passband selection performances.

Fiber-Optic Sensing Interrogation System for Simultaneous Measurement of Temperature and Transversal Loading Based on a Single-Passband RF Filter

In this paper, a fiber-optic sensing interrogation system for simultaneous measurement of temperature and transversal loading based on a single-passband RF filter has been proposed and experimentally demonstrated. This sensing interrogation system consists of a fiber Mach–Zehnder interferometer (FMZI) as the sensing device and a dispersive medium. The FMZI also acts as the spectrum slicer to induce continuous sampling, which results in the single-passband frequency response together with the dispersive medium. Two arms of the FMZI are used to measure the temperature and transversal loading respectively. The temperature change on one arm introduces the variation of fiber refractive index, which will change the central frequency of the RF filter’s passband, while the transversal loading induces the change of polarization state of the light, and thus, the amplitude of the RF filter’s passband will be changed accordingly. By tracking the central frequency and amplitude changes of the passband, temperature, and transversal loading can be monitored simultaneously. With the proposed fiber-optic sensing interrogation system, the temperature and transversal loading variation-induced optical spectra changes can be converted to the variation of frequency and amplitude of the RF filter’s passband in electronic domain, which greatly facilitates the measurement.

Sagnac interferometer with polarization maintaining fiber for vector transversal loading measurement

In this paper, a Sagnac interferometer with polarization maintaining fiber (PMF) for vector transversal loading measurement has been proposed and experimentally demonstrated. The light propagated in different axes of the PMF has different velocity because of fiber birefringence, which results in phase difference, and thus interferometer pattern is produced. When the birefringence parameters are affected by transversal loading, the phase difference of the light propagating in different axes will change, and as a result of the interferometer pattern of the Sagnac loop shifts. When transversal loading with the opposite direction is applied on the sensing fiber, the interferometer pattern also shifts, but oppositely to longer or shorter wavelength, by monitoring which vector transversal loading measurement can be achieved. The sensing characteristics when transversal loading is applied in different angles have also been studied. The proposed measurement method has a simple structure, and is easy to implement, which shows a good application prospects in the sensing field.

Fiber-optic sensing system for simultaneous measurement of temperature and transversal loading based on reflective fiber Mach-Zenhder interferometer

In this paper a fiber-optic sensing system for simultaneous measurement of temperature and transversal loading based on a dual-passband microwave photonic filter has been proposed and experimentally demonstrated. The proposed sensing system is simple in construction, and compares with single-passband RF filter system, our work enjoys higher sensitivity of the measurement.

Fiber-optic sensing interrogation based on a dual-passband microwave filter for simultaneous measurement of temperature and transversal loading

In this paper, a fiber-optic interferometer based simultaneous measurement of temperature and transversal loading by using dual-passband microwave photonic filter (MPF) has been proposed and experimentally demonstrated. The modified fiber Mach-Zehnder interferometer (FMZI) based sensor is used as the spectrum slicer, and along with the dispersive medium, dual-passband MPF can be realized. The changes on the FMZI will affect the transmission spectrum, and then the frequency response of the dual-passband MPF. In the experiment, the proposed method has been adopted for simultaneous measurement of temperature and transversal loading. One arm of the modified FMZI can be used for the temperature sensing, and the fiber between two outputs of the FMZI can be utilized to measure the transversal loading. By tracking the central frequency and the peak power of the passbands of the MPF, temperature and transversal loading changes can be demodulated.

A switchable and tunable dual-passband microwave photonic filter

In this article, we propose and demonstrate a new approach to implement microwave photonic filter with tunable and switchable dual-passband based on a reflective fiber Mach-Zehnder interferometer and dispersive medium. The proposed MPF has simple structure and is easy to implement, also the experimental results show good tunability and switch performances.

A tunable multi-passband microwave photonic filter

In this article, we have proposed and demonstrated two new approaches to implement microwave photonic filter with tunable multi-passband based on reflective fiber Mach-Zehnder interferometer and cascaded fiber Mach-Zehnder interferometers and dispersive medium. The proposed MPF has simple structure and is easy to implement, also the experimental results show good tunability and switch performances.