Fast four-channel fibre-optic displacement sensor for measuring impact waves at low cost

Abstract

We have developed a fast four-channel fibre-optic sensor for measuring dynamic surface displacements caused by shock waves. Light from an LED emitter is sent through a plastic fibre and reflected from the surface back into the fibre. The intensity of the reflected light gives the distance to the surface unambigously. Based on simple principles and utilizing inexpensive components, micrometre and microsecond resolution is achieved at lower cost and with easier usage than for interferometric methods and with better reliability than an accelerometer. The sensor is comparatively easy to set up. It is battery operated for reduced sensitivity to electromagnetic interference. The design of the fibre probe facilitates access in narrow and hostile environments.

High-G effects on optical fiber based displacement sensing for re-entry bodies

“…The design of the displacement sensor is similar to previous extrinsic fiber optic interferometric sensors based on the gap formed between the cleaved endfaces of two optical fibers [1,[4][5][6][7]. As shown in Figure 1, the sensor is fabricated by aligning the collimated output of a graded-index (GRIN) lens mounted on the end of an optical fiber at 90º to a reflective target surface [1].…”

“…The second is the standard deviation. The third moment is the skewness (S) calculated using the mean, y , and standard deviation, y σ seen in equation 3: (6) Similarly to the standard deviation of skewness, the deviation for kurtosis from equation 6 is an estimate for a Gaussian distribution. The value of 'K' should be believed if it is significantly different from ) (K σ .…”

Low‐cost educational resource using optical fibers to send 4‐bit images in grayscale

“…In the meantime, research on this topic has covered several amounts of areas that involve optical fibers, such as the improvement of the fiber materials and its capabilities, the lasers used to send information, the receivers, the algorithms of communication, and the creation of multiple sensors that take advantage of the fiber responses. For instance, a Light Emitting Diode has been used to reduce the cost in the emitter with an efficient result for sensors ; the information has also travelled through laser pulses [6,17], and it has been coded by polarization or by twisting the light . Also, multiple types of receivers have been used, including a simple photoresistor .…”

Development of an optical accelerometer for low-frequency vibration using the voice coil on a DVD pickup head

“…In their design, the device used an inertial mass that stressed or compressed an FBG, which caused its Bragg wavelength to increase or decrease in proportion to the acceleration. Nilsson et al [15] presented fast four-channel fiber-optic displacement. In their design, light from an LED emitter is sent through a plastic fiber and reflected from the surface back into the fiber.…”