FBG-based optical interface to support a multisector antenna in a spectrally efficient fiber radio system

We propose and demonstrate a fiber Bragg grating (FBG)-based optical interface for use in a spectrally efficient fiber-radio network with multisector antennas. The system has the novel feature of being specifically developed for use in existing wavelength-division-multiplexed network infrastructures. The proposed scheme supports transport of a remote local oscillator (LO) and three subcarrier multiplexed data channels, destined for different antenna sectors, using a single wavelength. The composite signal was contained within a 25-GHz band, selected via a 25-GHz dispersion-flattened FBG. Recovery of the LO and data channels is performed via optical filtering, using either a novel single grating incorporating multiple phase shifts or multiple narrow bandwidth gratings. Our measurements show that all channels within the 25-GHz band are successfully recovered with less than 2-dB optical power penalty between channels. The use of the 25-GHz grating exhibits an improvement in sensitivity of 3 dB for all data channels

Ultra Dense WDM Passive Optical Network based on RSOAs Facilitated through a Simple and Stable Seeding Source

European Conference on Optical Communication (ECOC)

Predicting the mean first passage time (MFPT) to reach any state for a passive dynamic walker with steady state variability

Idealized passive dynamic walkers (PDW) exhibit limit cycle stability at steady state. Yet in reality, uncertainty in ground interaction forces result in variability in limit cycles even for a simple walker known as the Rimless Wheel (RW) on seemingly even slopes. This class of walkers is called metastable walkers in that they usually walk in a stable limit cycle, though guaranteed to eventually fail. Thus, control action is only needed if a failure state (i.e. RW stopping down the ramp) is imminent. Therefore, efficiency of estimating the time to reach a failure state is key to develop a minimal intervention controller to inject just enough energy to overcome a failure state when required. Current methods use what is known as a Mean First Passage Time (MFPT) from current state (rotary speed of RW at the most recent leg collision) to an arbitrary state deemed to be a failure in the future. The frequently used Markov chain based MFPT prediction requires an absorbing state, which in this case is a collision where the RW comes to a stop without an escape. Here, we propose a novel method to estimate an MFPT from current state to an arbitrary state which is not necessarily an absorbing state. This provides freedom to a controller to adaptively take action when deemed necessary. We demonstrate the proposed MFPT predictions in a minimal intervention controller for a RW. Our results show that the proposed method is useful in controllers for walkers showing up to 44.1% increase of time-to-fail compared to a PID based closed-loop controller

Journal of stored products research

92

Bit rate identification using asynchronous delay-tap sampling

European Conference on Optical Communication (ECOC)

Cascaded nonlinear interactions for photonic time and wavelength switch constructed using a Fiber loop interferometer incorporated with a PPLN waveguide

Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies (CLEO/QELS and PhAST)

Time-slot coding scheme for multiple access in indoor optical wireless communications

This letter proposes what we believe is a novel time-slot coding (TSC) scheme to provide optical wireless communications to multiple users simultaneously with limited multiuser interference. We studied the proposed TSC experimentally and our results show that the code alignment tolerance, due to imperfect timing during the code generation process in practice, is 90.2%, 91.8%, and 93.1% with 4-QAM modulation at the received optical power of -22 dBm, -20 dBm, and -18 dBm, respectively. Furthermore, we also demonstrated a proof-of-concept experiment for simultaneous wireless connectivity for up to five users at multiple gross data rates (0.5 Gbps, 1 Gb/s, 1.6 Gb/s, 2 Gb/s, and 2.5 Gb/s)

Experimental demonstration of space-time-coded robust high-speed indoor optical wireless communication system

A space-time-coded 10 Gb/s indoor optical wireless communication system with robustness to physical shadowing is proposed and investigated. Experimental results show that the bit-error-rate performance can be improved by about 40%