Performance Comparison between 120 Gbit/s RZ-DQP-ASK and RZ-D8PSK over a 480 km Link

This paper experimentally presents the first direct comparison between two 120-Gbit/s 8-ary formats and show that both can be superior over different distances. The performances of two formats are also evaluated over three different dispersion-maps

Performance Comparison of Differential 8-Ary Modulation Formats in High-Speed Optical Transmission Systems

This paper presents back-to-back and transmission performance comparisons between single-polarization 120 Gbit/s RZ-DQP-ASK and RZ-D8PSK formats in a single-wavelength system. In the back-to-back configuration, we determine the OSNR requirements of the two formats and compare the results with those obtained analytically and numerically. In the transmission experiments, we examine signal constellations to quantify the significance of intra-channel fiber nonlinearities and investigate the BER performance of the two formats over different reaches (up to 480 km). The results show that the performance of DQP-ASK is superior to D8PSK in back-to-back configuration but is inferior over long distances

Locally finitely presented categories and functor rings

In this paper, 40 Gbaud transmission of single polarization (SP) and Polarization-Multiplexed (PM), RZ-DQPSK and RZ-D8PSK signals is analyzed numerically. The impact of nonlinear crosstalk arising from the presence of neighbouring intensity-modulated channels is analyzed in terms of required OSNR for the BER of 10-3versus launch power.QC 20120607</p

Influence of Fiber-Bragg Grating-Induced Group-Delay Ripple in High-Speed Transmission Systems

The implementation of a chirped fiber-Bragg grating (FBG) for dispersion compensation in high-speed (up to 120 Gbit/s) transmission systems with differential and coherent detection is, for the first time, experimentally investigated. For systems with differential detection, we examine the influence of group-delay ripple (GDR) in 40 GBd 2-, 4-, and 8-ary differential phase shift keying (DPSK) systems. Furthermore, we conduct a nonlinear-tolerance comparison between the systems implementing dispersion-compensating fibers and FBG modules, using a 5 x 80 Gbit/s 100-GHz-spaced wavelength division multiplexing 4-ary DPSK signal. The results show that the FBG-based system provides a 2 dB higher optimal launch power, which leads to more than 3 dB optical signal-to-noise ratio (OSNR) improvement at the receiver. For systems with coherent detection, we evaluate the influence of GDR in a 112 Gbit/s dual-polarization quadrature phase shift keying system with respect to signal wavelength. In addition, we demonstrate that, at the optimal launch power, the 112 Gbit/s systems implementing FBG modules and that using electronic dispersion compensation provide similar performance after 840 km transmission despite the fact that the FBG-based system delivers lower OSNR at the receiver. Lastly, we quantify the GDR mitigation capability of a digital linear equalizer in the 112 Gbit/s coherent systems with respect to the equalizer tap number (N-tap). The results indicate that at least N-tap = 9 is required to confine Q-factor variation within 1 dB

Optical injection-locking-based pump recovery for phase-sensitively amplified links

An injection-locking-based pump recovery system for phase-sensitively amplified links is proposed and studied experimentally. Measurements with 10 Gbaud DQPSK signals show penalty-free recovery of 0.8 GHz FWHM bandwidth pump with 63 dB overall amplification

Injection locking-based pump recovery for phase-sensitive amplified links

An injection locking-based pump recovery system for phase-sensitive amplified links, capable of handling 40 dB effective span loss, is demonstrated. Measurements with 10 GBd DQPSK signals show penalty-free recovery of a pump wave, phase modulated with two sinusoidal RF-tones at 0.1 GHz and 0.3 GHz, with 64 dB amplification. The operating power limit for the pump recovery system is experimentally investigated and is governed by the noise transfer and phase modulation transfer characteristics of the injection-locked laser. The corresponding link penalties are explained and quantified. This system enables, for the first time, WDM compatible phase-sensitive amplified links over significant lengths

Multi-level modulation formats for high-speed optical transmission systems

Over the past several years, the use of multi-level modulation formats has enabledsignificant improvements in the field of optical fiber communication, particularlyin terms of per-channel bit-rate (i.e., line-rate) and spectral efficiency (SE), byencoding multiple bits per symbol. This has resulted in a wide range of demonstrationsof optical systems with line-rates beyond 100 Gbit/s, which are of greatinterest for next-generation optical communication. However, as each modulationformat exhibits unique characteristics even among those having an equal numberof modulation levels (e.g., receiver sensitivity, susceptibility to impairments,and implementation complexity/cost), it is very challenging to specify an optimummodulation scheme for particular applications without appropriate knowledge ofmodulation formats. As a consequence, the characterization of multi-level modulationformats is regarded as an area of key importance in this research field.This thesis is devoted to demonstrations of high-speed optical transmission systemsthrough the use of various multi-level modulation formats as well as signalcharacterization, in-depth assessment of several transmission impairments, and performancecomparisons among different formats. The work included in this thesiscan be divided into two parts, based upon the detection technique used in the receiver.The first part concerns optical systems with differential detection, includingthe demonstrations of (up to) 0.96 Tbit/s transmission over a single wavelength, impairmentassessments of M-ary phase shift keying (M = 2, 4, 8) at the symbol-rateof 40 Gbaud, and a performance comparison of two 8-ary formats at the line-rateof 120 Gbit/s. The second part deals with optical systems with coherent detection,covering the demonstration of 16-ary quadrature amplitude modulation with anSE of 7.2 bit/s/Hz and the performance comparison of two modulation formatsfor wavelength-division multiplexed systems with an SE of 4.1 bit/s/Hz. In addition,the work included in the thesis addresses the implementation of chirped fiberBragg gratings for dispersion compensation and their impact in high-speed opticalsystems with both differential and coherent detection

Multi-level modulation formats for high-speed optical transmission systems

Over the past several years, the use of multi-level modulation formats has enabledsignificant improvements in the field of optical fiber communication, particularlyin terms of per-channel bit-rate (i.e., line-rate) and spectral efficiency (SE), byencoding multiple bits per symbol. This has resulted in a wide range of demonstrationsof optical systems with line-rates beyond 100 Gbit/s, which are of greatinterest for next-generation optical communication. However, as each modulationformat exhibits unique characteristics even among those having an equal numberof modulation levels (e.g., receiver sensitivity, susceptibility to impairments,and implementation complexity/cost), it is very challenging to specify an optimummodulation scheme for particular applications without appropriate knowledge ofmodulation formats. As a consequence, the characterization of multi-level modulationformats is regarded as an area of key importance in this research field.This thesis is devoted to demonstrations of high-speed optical transmission systemsthrough the use of various multi-level modulation formats as well as signalcharacterization, in-depth assessment of several transmission impairments, and performancecomparisons among different formats. The work included in this thesiscan be divided into two parts, based upon the detection technique used in the receiver.The first part concerns optical systems with differential detection, includingthe demonstrations of (up to) 0.96 Tbit/s transmission over a single wavelength, impairmentassessments of M-ary phase shift keying (M = 2, 4, 8) at the symbol-rateof 40 Gbaud, and a performance comparison of two 8-ary formats at the line-rateof 120 Gbit/s. The second part deals with optical systems with coherent detection,covering the demonstration of 16-ary quadrature amplitude modulation with anSE of 7.2 bit/s/Hz and the performance comparison of two modulation formatsfor wavelength-division multiplexed systems with an SE of 4.1 bit/s/Hz. In addition,the work included in the thesis addresses the implementation of chirped fiberBragg gratings for dispersion compensation and their impact in high-speed opticalsystems with both differential and coherent detection