Multi-fiber WDM networks are becoming the major telecommunication platforms for transmitting exponentially increasing data traffic. While today’s networks are mainly providing circuit-switched connections, optical packet-switching technologies have been investigated for years, aiming at achieving more efficient utilizations of network resources. In this paper, we have evaluated, for the first t...

this paper presents a novel control method to improve the efficiency of low-voltage dc-dc converters at light loads. pulse width modulation (pwm) converters have poor efficiencies at light loads, while pulse frequency modulation (pfm) control is more efficient for the same cases. switching losses constitute a major portion of the total power loss at light loads. to decrease the switching losses...

The Internet’s simple design resulted in huge success in basic telecommunication services. However, in terms of providing end-to-end QoS services, the Internet’s architecture needs major shifts since it neither allows (i) users to indicate their value choices at sufficient granularity nor (ii) providers to manage risks involved in investment for new innovative QoS technologies and business rela...

Multistage Interconnection Networks (MIN) are popular in switching and communication applications. It has been used in telecommunication and parallel computing systems for many years. The new challenge facing optical MIN is crosstalk, which is caused by coupling two signals within a switching element. Crosstalk is not too big an issue in the Electrical Domain, but due to the stringent Bit Error...

We propose a time-dependent network of innnite-server queues to help a service provider manage a family of private-line telecommunication services. The queueing network is used to model switching from one service to another. The relevant time scale is quite long: service lifetimes are measured in years, while service life cycles are measured in decades. To capture changing technology and custom...

Recently malfunctions of telecommunication installations caused by switching noises of electric equipment or devices have been increasing. The switching noises usually have low frequency components less than 50Hz and also more than 9kHz or 150 kHz. It is useful to detect power spectrum of noises in order to solve EMC problems. The LPC (Linear Prediction Code) method is known as a powerful frequ...

Telecommunication networks are experiencing a dramatic increase in demand for capacity, much of it related to the exponential takeup of the Internet and associated services. To support this demand economically, transport networks are evolving to provide a reconfigurable optical layer which, with optical cross-connects, will realize a high-bandwidth flexible core. As well as providing large capa...

After light became a part of the telecommunication system, the manipulation of light, especially the control of the speed of light, became a focus of research. By using the different approaches of the interaction between light and matter, there have been many successful attempts to slow down the speed of light, even to several meters per second. In the first part of my thesis, I studied pulse p...

Black phosphorus (BP) has recently been rediscovered as a new and interesting two-dimensional material due to its unique electronic and optical properties. Here, we study the linear and nonlinear optical properties of BP flakes. We observe that both the linear and nonlinear optical properties are anisotropic and can be tuned by the film thickness in BP, completely different from other typical t...