Abstract:The success of any perimeter intrusion detection system depends on three important performance parameters: the probability of detection (POD), the nuisance alarm rate (NAR), and the false alarm rate (FAR). The most fundamental parameter, POD, is normally related to a number of factors such as the event of interest, the sensitivity of the sensor, the installation quality of the system, and the reliability of the sensing equipment. The suppression of nuisance alarms without degrading sensitivity in fiber optic intrusion detection systems is key to maintaining acceptable performance. Signal processing algorithms that maintain the POD and eliminate nuisance alarms are crucial for achieving this. In this paper, a robust event classification system using supervised neural networks together with a level crossings (LCs) based feature extraction algorithm is presented for the detection and recognition of intrusion and non-intrusion events in a fence-based fiber-optic intrusion detection system. A level crossings algorithm is also used with a dynamic threshold to suppress torrential rain-induced nuisance alarms in a fence system. Results show that rain-induced nuisance alarms can be suppressed for rainfall rates in excess of 100 mm/hr with the simultaneous detection of intrusion events. The use of a level crossing based detection and novel classification algorithm is also presented for a buried pipeline fiber optic intrusion detection system for the suppression of nuisance events and discrimination of intrusion events. The sensor employed for both types of systems is a distributed bidirectional fiber-optic Mach-Zehnder (MZ) interferometer.
A novel resonantly enhanced Mach-Zehnder modulator with 10 dE3 enhancement in link performance is demonstrated. Enhancement is achieved through placement of the electrode structure within a Fabry-Perot type cavity. Theoretical prediction and experimental verification are presented.
A systematic design approach using the developed numerical model for the investigation of any arbitrary electrooptic modulator configuration is described, and its application to the simulation and synthesis of resonantly enhanced Mach-Zehnder modulators (RE-MZMs) is demonstrated. The tool is implemented using equivalent circuit model using transmission lines, lumped elements, and N-port S-parameters. The numerical tool is used to simulate the modulation enhancement factor and radio frequency (RF) return loss of a number of theoretically and experimentally demonstrated examples. Finally, the design tool is used to synthesize a new optimized RE-MZM. This RE-MZM is fabricated and measured, and predicted results are compared.
An RF-photonic link using an optimized resonantly-enhanced optical intensity modulator (RE-MZM) is demonstrated. The enhanced modulator provides a 9dB link gain improvement when compared to a commercial, broadband modulator with a 3dB bandwidth of 11%. The noise figure of the link is experimentally measured as a function of optical power. Comparison to an un-enhanced modulator demonstrates that when the link noise is laser RIN limited, the enhanced modulator provides a significant improvement to noise figure. The intermodulation distortion of RE-MZM link is also analyzed and it is shown that the resonant enhancement does not impact modulation dynamic range.
Optical modulators using "Lithium Niobate" (LiNb03) have become the industry standard for high-speed data transmission and RF photonic links. Packaging is a determining factor in maintaining low cost and highperformance. This paper investigates the application of flip chip technology to optical modulator packaging. Experimental results show that rugged flip chip bonds can be realized with minimal impact on the modulator electrical performance.
The suppression of nuisance alarms without degrading sensitivity in fibre-optic intrusion detection systems is important for maintaining acceptable performance. Signal processing algorithms that maintain the POD and minimize nuisance alarms are crucial for achieving this. A level crossings algorithm is presented for suppressing torrential rain-induced nuisance alarms in a fibre-optic fence-based perimeter intrusion detection system. Results show that rain-induced nuisance alarms can be suppressed for rainfall rates in excess of 100 mm/hr, and intrusion events can be detected simultaneously during rain periods. The use of a level crossing based detection and novel classification algorithm is also presented demonstrating the suppression of nuisance events and discrimination of nuisance and intrusion events in a buried pipeline fibre-optic intrusion detection system. The sensor employed for both types of systems is a distributed bidirectional fibre-optic Mach Zehnder interferometer.
Abstract-A resonantly enhanced modulator structure with cascaded multiple resonant cavities is proposed and analyzed. The microwave effective index of the electrode can be much higher than the optical index. Therefore, the electrode structure can be optimized for high modulation efficiency and high resonant enhancement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.