Optical router for optical fiber sensor networks based on a liquid crystal cell

Abstract

Abstract-Optical fiber sensor networks are evolving rapidly. They are used because of the inert nature of optical fibers allowing no electromagnetic interference and safe applications in inflammable atmospheres; other relevant characteristics are their low weights and wide bandwidths as a transmission medium. In any case, it is very interesting to have specific components such as optical routers for selecting a certain path in a network with no optical to electrical and electrical to optical conversions. In this paper, we propose an all-optical router based on liquid crystals, polarizers, and a spatial split polarization beam splitter. The implemented device is designed to operate with visible light and it has been tested with plastic optical fibers. It has a crosstalk of 14 dB between selected ON channels and nonoperative OFF channels and 11-dB insertion losses. An average switch time of 100 ms is measured. The device checks the optical power level in each channel and, in case of failure, automatically switches to an operative channel while an alarm is activated.Index Terms-Liquid crystal cell, optical router, sensor network.

Broadband 1×2 liquid crystal router with low thermal dependence for polymer optical fiber networks

“…The proposed PR design allows a significant improvement of the spectral response of LC optical routers, as in those previously reported [10,11,19,20], in a broadband range, and may even improve the response of LC devices reported recently [23]. The experimental results show that the proposed router has quite similar values of IL in both outputs (OFF and ON states) in the range from 400-nm, as well as CT values lower than À18.68 dB.…”

“…Usually, and especially in applications where channel equalization is needed, LC-ORs use twisted nematic (TN) LC cells, acting as polarization rotators (PRs) with a continuous operation mode (intermediate transmission levels) [19,20]. However, their performance is optimum only for specific wavelengths (Mauguin Minima) [21].…”

1 × 2 Optical Router With Control of Output Power Level Using Twisted Nematic Liquid Crystal Cells

“…EO switches include those based on liquid crystal (LC) devices [7][8][9]. LC routers use different physical mechanisms to steer the light such as polarization management, reflection, wave-guiding and beam-steering (2D or 3D).…”

Optical Computing Devices Based on Photonic Liquid Crystal Layers

“…The crosstalk performance of the optical router device is calculated as follows [32]: Here, P on is the power received by the active port in any of the three different modes of operation and P off is the leaky power received by either of the two other ports. In this study, the device crosstalk reports a value around 19 dB in any case.…”