In this paper, a bending sensor based on distributed Bragg reflector (DBR) fiber laser with single longitudinal mode
operation is presented and experimentally demonstrated. The single longitudinal mode has two split orthogonal
polarization modes, introducing the intracavity birefringence and hence causing the emergence of frequency beat. Based
on the bending induced birefringence, this laser can be used for curvature sensing by measurement of the beat frequency
shift of polarization mode. The sensing characteristics of the laser were shown in detail through theoretical analysis and
In this paper, a pressure sensor based on distributed Bragg reflector (DBR) fiber laser
was reported. The laser was operated in single longitudinal mode. For the longitudinal-mode has
two orthogonal polarizations, external press on the cavity would induce birefringence. It can be
used to sense external pressure by measuring the beat frequency shift of polarization mode. After
theoretical derivation and experimental verification, the sensing characteristics of the laser were
shown in detail.
In this letter, a novel optical sensor based on high birefringence fiber loop mirror with a
single Fiber Bragg Grating, available for temperature insensitive measurement for strain, was
proposed and demonstrated. Considering that the HBFLM (high birefringence fiber loop mirror)
and the conditional Fiber Bragg Grating have different response to strain and temperature,
respectively, we can detect both the peak wavelength shift of these two devices. So we can build a
lineal matrix equation between the perturbation of the surrounding and the shift of the
transmission spectrum. Compared with conditional sensors for simultaneous measurement, this
kind of sensor has several advantages, including simple configuration, low cost and easy to be
A fiber loop consists of two couplers and a single mode fiber and the measured pressure is converted into ringdown time of light traveling in the fiber loop by the sensor element of FBG. When pressure is changed, the pressure will be directly proportional to the ringdown time which is identical to that of theory. This kind of system of measuring press based on the theory has advantages of simple composition and convenient measure and it provides a novel method of fiber gratting demodulation technology and has practical value. Apart from measuring press, it can measure temperature and other parameters.
In this paper, a novel 3D strain FBG sensor based on cylinder structure is reported. In our
experiment, we used 3 FBGs as sensing element and fixed them on the side of the cylinder according to
120° angle intervals. Based on the physical and mathematics principle, theoretical derivations and
experiment setup were also showed. In application, this sensor would have a good prospect.
Long-period grating(LPG) which has a grating period of more than 100μm is a new kind of fiber gratting and its principle is that optical power is coupled from the forward transmission fundamental core mode to the forward transmission cladding modes and is attenuated after some distance. Transmission spectrum of LPG has a range close to linearity in both side of the peak. This range can be use as double edge filter on this property. Cascaded LPGs have special spectrum which is used as filters in multiple technology.
Experiments using high birefringence fiber Sagnac loop mirror as the temperature sensor are reported. We study
the characteristics of this sensor based on intensity detection. The result is linear in the measurable range. The sensing
sensitivities of temperature is 0.92nm/°C, which is nearly 89 times larger than the typical temperature sensitivities of fiber
In this paper, a temperature insensitive fiber Bragg grating (FBG) sensor based on wheel-type structure
pressure box is presented. Using two fiber Bragg gratings, within the pressure range of 0~30KN, its
linearity and sensitivity reach 99.98% and 13.89N, respectively.
We bring forward a novel FBG sensor multiplexing technique based on Petri Net theory and the wavelength/spatial-division multiplexing technique. With this technique, the FBG sensing system not only avoid frequently switching and improve the average response speed, but also is able to enact data acquisition rule according to the priority (PRI), the delay time and the wavelength shift of FBG sensors. Therefore, the smart FBG sensors multiplexing system is more rational and smarter than the conventional WDM/SDM multiplexing technique. To validate the feasibility and advantage of the multiplexing technology, a FBG strain sensing system and theory simulation were proposed. The resolution power of the sensing system is 1με. The average delay time of the technique is lower one magnitude order than the conventional ones.