Significant improvements in optical power budgets of real-time optical OFDM PON systems.

Based on a comprehensive theoretical optical orthogonal frequency division multiplexing (OOFDM) system model rigorously verified by comparing numerical results with end-to-end real-time experimental measurements at 11.25Gb/s, detailed explorations are undertaken, for the first time, of the impacts of various physical factors on the OOFDM system performance over directly modulated DFB laser (DML)-based, intensity modulation and direct detection (IMDD), single-mode fibre (SMF) systems without in-line optical amplification and chromatic dispersion compensation. It is shown that the low extinction ratio (ER) of the DML modulated OOFDM signal is the predominant factor limiting the maximum achievable optical power budget, and the subcarrier intermixing effect associated with square-law photon detection in the receiver reduces the optical power budget by at least 1dB. Results also indicate that, immediately after the DML in the transmitter, the insertion of a 0.02nm bandwidth optical Gaussian bandpass filter with a 0.01nm wavelength offset with respect to the optical carrier wavelength can enhance the OOFDM signal ER by approximately 1.24dB, thus resulting in a 7dB optical power budget improvement at a total channel BER of 1 × 10(-3).

Inserting innovations in-service

Military platforms have exceptionally long lifecycles and given the state of defense budgets there is a significant trend in sustaining the operational capability of legacy platforms for much greater periods than originally designed. In the context of through-life management, one of the key questions is how to manage the flow of technology for platform modernization during the in-service phase of the lifecycle? Inserting technological innovations in-service is achieved through technology insertion processes. Technology insertion is the pre-eminent activity for both maintaining and enhancing the functional capability of a platform especially given the likely changes in future military operations, the pace of change in technology and with the increasing focus on lifecycle cost reduction. This chapter provides an introduction to technology insertion together with an overview of the key issues that practitioners are faced with. As an aid to planning technology insertion projects, a decision-support framework is presented. © 2010 Springer-Verlag Berlin Heidelberg.

7dB optical power budget improvements of optical OFDM PON systems using narrow optical filters

The use of 0.02nm bandwidth optical bandpass filters with 0.01nm wavelength offsets from optical carrier wavelengths in the optical OFDM (OOFDM) transmitter improves optical power budgets by 7dB at a total channel BER of 1×10 -3 in directly modulated laser-based IMDD PON systems. ©2010 Optical Society of America.