"The burgeoning capacity demand for both optical transport links over metro / long-haul distances (> 100km) and short reach optical interconnects (100m-20km) for inter- and intra-datacenter networking is driving the notion of a digital signal processing (DSP) based optical transceiver. In optical transport, flexible optical transceivers employ coherent detection and DSP to enable mitigating various fiber transmission impairments such as chromatic dispersion (CD), polarization mode dispersion (PMD), Kerr nonlinearity, laser phase noise and frequency offset. In addition, these flexible transceivers need to be agile enough to adapt to the increasingly dynamic network traffic needs (e.g. varying capacity and reach requirements, dynamic wavelength assignments). On the short reach side, cheap and power efficient optics is a necessity for datacenter applications and hence intensity modulation / direct-detection (IM/DD) prevails over coherent detection. For such IM/DD transceivers, photonic integration is envisioned to play a significant role in reducing the cost along with DSP that potentially allows increasing the delivered bit rates with cheap electronics and reduced number of optical components (and consequently footprint).In the first part of the thesis, we propose and verify, both analytically and experimentally, a myriad of DSP algorithms suitable for implementation in flexible optical coherent transceivers for transport networks. The proposed DSP algorithms tackle impairments such as laser phase noise, frequency offset, polarization rotation, fiber Kerr nonlinearity and sampling frequency offset. For each of the proposed algorithms, we provide a performance comparison with the standard counterparts in the literature highlighting the advantages of our approaches together with the underlying tradeoffs. Next, we develop and experimentally verify a rigorously derived analytical model for performance evaluation of a flexible coherent optical front-end that can operate colorlessly in a wavelength division multiplexing (WDM) scenario, i.e. without the need for a WDM demultiplexing filter prior to the receiver. The accuracy of the developed model was proved by finding a close match between model predictions and experimental results. We finally show that the model can be used as a useful system design tool to predict the system performance at various operating scenarios.In the last part of the thesis, we propose a DSP algorithm to enable polarization division multiplexing (PDM) in IM/DD transceivers for short reach optical interconnects. This doubles the achievable bit rate with the same speed of the electronic components and with the same number of light sources by exploiting the two orthogonal polarization states per source. The proposed DSP algorithm is based on a multiple-input and multiple-output (MIMO) finite impulse response (FIR) filter that operates on the Stokes parameters of the received field, which can be obtained via a direct-detection receiver front-end, to invert the random rotations that occurred along the fiber. The proposed DSP was verified experimentally using an IM/DD transceiver that employs a single 1310 nm laser whose both polarizations were modulated by a packaged silicon photonic (SiP) intensity modulator. A record bit rate of 224 Gb/s was transmitted over 10 km with a BER below the forward-error-correcting (FEC) threshold." --

"As data center traffic increases, challenges rise for existing optical transceivers. For data center interconnects (DCIs) transmission distance matters and drives specifications of optical transceivers. For metro and long reach DCIs (>100 km), high bit rate and small form factor is imperative for next-generation transceiver. The advent of high speed digital-to-analog (DAC) and analog-to-digital converters (ADC), and recent progress in complementary metal-oxide-semiconductor (CMOS) as well as in integrated photonic technology has facilitated the development of optical transceivers relying on coherent detection employing digital signal processing (DSP). On extended reach DCIs (

"Next generation coherent optical transports for core networks are anticipated to further approach the Shannon limit for a higher fiber capacity by delivering 400 Gb/s or 1 Tb/s data rates per channel, and providing flexibility and agility to maximize the network resource utilization. This thesis looks into novel system architectures and digital signal processing (DSP) algorithms to fulfill those design targets. The single carrier and orthogonal frequency-division multiplexing (OFDM) modulation schemes are both potential candidates for the underlying transceiver architecture. We provide the analysis and investigation of the optical channel impairments for both systems in the context of >100 Gb/s transmissions with higher symbol rates and higher order quadrature amplitude modulation (QAM). With an increased accumulated chromatic dispersion (CD) for a single channel, the impacts of laser phase noise and fiber nonlinearities manifest new characteristics which are not evident in current 100G systems. We propose novel and energy-efficient DSP algorithms and system designs to increase laser linewidth tolerance and reduce nonlinear noise. The performances of the proposed designs are experimentally evaluated using a leading-edge optical long-haul transmission testbed, which was custom built for this thesis. The single carrier and OFDM systems are separately explored and compared, and it is shown that OFDM has certain multi-carrier advantages when a large accumulated CD exists. This result implies that the OFDM scheme may be a better option for next generation transceivers than the currently employed 100G single carrier transceiver scheme. In the last part, we concentrate on the design of flexible optical transceivers for future software-defined optical networks. The following novel techniques are proposed to achieve a full flexibility without increasing the cost: format-transparent DSP platform, agile bandwidth allocation, and continuous modulation format." --

As we reach the data transmission limits of copper wire and communications experts seek to bring the speed of long-haul fiber optics networks closer to access points, optical interconnects promise to provide efficient, high-speed data transmission for the next generation of networks and systems. They offer higher bit-rates, virtually no crosstalk, lower demands on power requirements and thermal management, and the possibility of two-dimensional channel arrays for chip-to-chip communication. The Handbook of Optical Interconnects introduces the systems and devices that will bring the speed and quality of optical transmission closer to the circuit board. Contributed by active experts, most from leading technology companies in the US and Japan, this outstanding handbook details various low-cost and small-size configurations, illustrates the discussion with more than 300 figures, and offers a look at the applications and future of this exciting and rapidly growing field. The book includes a detailed introduction to vertical cavity surface-emitting lasers (VCSELs); the use of optical interconnects in metropolitan, local-area, and access networks through FTTP (FTTH); and Jisso technologies, which are critical for developing low-cost, small-size modules. Driving down the size and cost of optical interconnects is vital for integrating these technologies into the network and onto microprocessors, and the Handbook of Optical Interconnects provides the knowledge and tools necessary to accomplish these goals.

This book explores the unique advantages and large inherent transmission capacity of optical fiber communication systems. The long-term and high-risk research challenges of optical transceivers are analyzed with a view to sustaining the seemingly insatiable demand for bandwidth. A broad coverage of topics relating to the design of high-speed optical devices and integrated circuits, oriented to low power, low cost, and small area, is discussed.Written by specialists with many years of research and engineering experience in the field of optical fiber communication, this book is essential for an audience dedicated to the development of integrated electronic systems for optical communication applications. It can also be used as a supplementary text for graduate courses on optical transceiver IC design.

Compiling the most influential papers from the IEICE Transactions in Communications, High-Performance Backbone Network Technology examines critical breakthroughs in the design and provision of effective public service networks in areas including traffic control, telephone service, real-time video transfer, voice and image transmission for a content delivery network (CDN), and Internet access. The contributors explore system structures, experimental prototypes, and field trials that herald the development of new IP networks that offer quality-of-service (QoS), as well as enhanced security, reliability, and function. Offers many hints and guidelines for future research in IP and photonic backbone network technologies