We perform experimental and numerical investigations of the transmission reach of polarization-switched QPSK (PS-QPSK) and polarization-multiplexed QPSK (PM-QPSK) for three different fiber span lengths: 83, 111 and 136 km. In the experimental comparison we investigate the performance of PS-QPSK at 20 Gbaud and PM-QPSK at the same bit rate (60 Gbit/s) and at the same symbol rate, both the single...

A new modulation technique, "SP-QPSK" (sinusoidal shaped d4-QPSK) suitable for land-mobile and satellite digital broadcasting systems applications is introduced. In digital data and/or sound broadcasting systems, which may have a relatively low bit rate transmission requirement, the residual phase noise introduced by the Doppler shift of moving vehicles presents a high bit error floor in cohere...

We propose and experimentally verify a novel approach to achieve phase-coherence orthogonally polarized optical single sideband (OSSB) modulation with a tunable optically carrier-to-sideband ratio (OCSR). In our scheme, the orthogonally polarized OSSB signal is achieved using a dual-polarization quadrature phase shift keying (DP-QPSK) modulator without an optical band-pass filter (OBPF). Theref...

We compare by simulation the performance of 100 Gbit/s PDM-iRZ-QPSK and PS-QPSK transmission both in homogeneous and hybrid QPSK/OOK DM links. We detail the reasons of the overall performance investigating each nonlinear effect (SPM, XPM and XPolM) individually. Moreover, we compare the accuracy of the noise loading method with the more realistic use of noisy in-line amplifiers. Results shows t...

We present the first experimental results for polarization-switched QPSK (PS-QPSK) and make a comparison with polarization-multiplexed QPSK. Our measurements confirm the predicted sensitivity advantage of PS-QPSK. We have also studied the single channel performance after transmission over 300 km and support the results with numerical simulations. It is shown that the two modulation formats have...

Coherent-detection (CoD) permits to fully exploit the four-dimensional (4D) signal space consisting of the in-phase and quadrature components of the two fiber polarizations. A well-known and successful format exploiting such 4D space is Polarization-multiplexed QPSK (PM-QPSK). Recently, new signal constellations specifically designed and optimized in 4D space have been proposed, among which pol...

This paper proposes a Quadrature Phase Shift Keying (QPSK) using two different methods. QPSK is one of the forms of Phase Shift Keying (PSK) modulation scheme. Generally a conventional QPSK modulator with Direct Digital Synthesizer (DDS) and arithmetic multiplier separates base band signal into I and Q phase which consumes low throughput with complexity in hardware implementation. Hence to gene...

By using a generalized cost function, a modified constant modulus algorithm (CMA) that allows polarization demultiplexing and equalization of polarization-switched QPSK is found. An implementation that allows easy switching between the conventional and the modified CMA is described. Using numerical simulations, the suggested algorithm is shown to have similar performance for polarization-switch...

In this paper we present Walsh-quadrature phase-shift keying (Walsh-QPSK) pseudonoise (PN) modulation schemes for both coherent and noncoherent direct-sequence code-division multiple-access (DS-CDMA) systems, wherein the PN spreading sequences for in-phase and quadrature data in a conventional QPSK PN modulation scheme are coded by Walsh sequences indexed by a special rule to reduce the envelop...

Quadrature Phase Shift Keying (QPSK) is a modulation scheme commonly used in wireless communication system and it’s because of its ability to transmit twice the data rate for a given bandwidth. In most cases, the QPSK modulator consumes less power and bandwidth in a modern devices but for a system like satellite and mobile devices where their operations are power limited, this is a problem that...