Optical communications : past, present and future trends

In this talk we will review some of the key enabling technologies of optical communications and potential future bottlenecks. Single mode fibre (SMF) has long been the preferred waveguide for long distance communication. This is largely due to low loss, low cost and relative linearity over a wide bandwidth. As capacity demands have grown SMF has largely been able to keep pace with demand. Several groups have been identifying the possibility of exhausting the bandwidth provided by SMF [1,2,3]. This so called “capacity-crunch” has potentially vast economic and social consequences and will be discussed in detail. As demand grows optical power launched into the fibre has the potential to cause nonlinearities that can be detrimental to transmission. There has been considerable work done on identifying this nonlinear limit [4, 5] with a strong re- search interest currently on the topic of nonlinear compensation [6, 7]. Embracing and compensating for nonlinear transmission is one potential solution that may extend the lifetime of the current waveguide technology. However, at sufficiently high powers the waveguide will fail due to heat-induced mechanical failure. Moving forward it be- comes necessary to address the waveguide itself with several promising contenders discussed, including few-mode fibre and multi-core fibre.

Uneasy lies the head that bears the trust:the effects of feeling trusted on emotional exhaustion

The construct of feeling trusted reflects the perception that another party is willing to accept vulnerability to one's actions. Although this construct has received far less attention than trusting, the consensus is that believing their supervisors trust them has benefits for employees' job performance. Our study challenges that consensus by arguing that feeling trusted can be exhausting for employees. Drawing on Stevan Hobfoll's conservation of resources theory, we develop a model in which feeling trusted fills an employee with pride a benefit for exhaustion and performance while also increasing perceived workload and concerns about reputation maintenance burdens for exhaustion and performance. We test our model in a field study using a sample of public transit bus drivers in London, England. Our results suggest that feeling trusted is a double-edged sword for job performance, bringing with it both benefits and burdens. Given that recommendations for managers generally encourage placing trust in employees, these results have important practical implications.