This effort focuses on the comparison of On Off Keying (OOK) to incoherent 4-ary Amplitude Shift Keying (ASK). We show that a 0.4 bits/s/Hz improvement in spectral efficiency is obtained by utilising 4-ary ASK. We determined the filter steepness required to achieve this maximum obtainable spectral efficiency. The comparison of OOK and 4-ary ASK in terms of dispersion tolerance for Non-Return-to...

We propose a scheme to achieve regenerative format conversion from a distorted non-return-to-zero-on-off-keying (NRZ-OOK) signal to a return-to-zero-binary-phase-shift-keying (RZ-BPSK) signal of high quality in an integrated device. This proposal is achieved by employing an interferometer on a silicon chip with a coupled ring resonator optical waveguide embedded in one arm. In this scheme the a...

We propose the multicarrier on–off keying (MC-OOK) as a bandwidth-efficient modulation method for frequency-hopped multiple-access (FHMA) communications. The motivation for using MC-OOK is that a more bandwidth-efficient modulation scheme allows a larger number of frequency slots, and thus provides a higher immunity against multiple-access interference in FHMA systems. We analyze the average bi...

This paper investigates the performance of digital pulse interval modulation (DPIM) in the presence of multipath propagation and additive white Gaussian noise. The results for optical power requirements normalised to the average optical power required by the on-and-off keying (OOK) verses the channel normalised delay spread for DPIM without guard band and with guard bands are presented, and are...

Polarization-insensitive conversion of return-to-zero (RZ) ON-OFF keying (RZ-OOK) to RZ binary phase-shift keying (RZ-BPSK) has been achieved by cross-phase modulation (XPM) in a nonlinear birefringent fiber. This work presents a theoretical analysis of the dependence of format conversion on pump-probe detuning, and the pump state-of-polarization (SOP) that can fluctuate unpredictably in a real...

The exponentially-growing mobile data traffic imposes significant demands on the capacity of the mobile network. Fiber optic and microwave links are two main solutions for the mobile backhaul network, which provides connectivity between radio base station (RBS) sites and the switch sites. As compared to fiber, a microwave solution is much easier to deploy, however, its capacity is lower. This t...

The authors model and characterise the performance of 10 Gbit/s 4-ary amplitude shift keying (ASK) systems in dispersive environments at 1550 nm. Both non-return-to-zero (NRZ) and return-to-zero (RZ) formats are examined, with comparisons to on-off keying (OOK) in each case. Both single amplified links and cascaded fibre-amplifier links are modelled. While 4-ary ASK systems suffer a back-to-bac...

Power and cost efficient short-range optical links are one of the technologies enabling large scale high-performance computers and data centers. Such links typically use directly modulated vertical cavity surface emitting lasers, multi-mode fiber, direct detection and on-off keying (OOK) modulation. In this work replacement of OOK with multilevel modulation formats is studied, with possible app...

In this paper we numerically investigate nonlinear impairments in a WDM system with mixed PM (D)QPSK and OOK channels. First we analyze the dependence of XPM and XPolM on SOP and baud rate in absence of PMD. In this case we find that the nonlinear impairments are highly dependent on relative SOP between the PM (D)QPSK and neighbouring OOK channels. The dependence on relative SOP is more pronoun...