Performance of Dual-Polarization QPSK for Optical Transport Systems

Abstract

Abstract-The emergence of capable semiconductor processes has allowed digital signal processing to extend the application range of high-capacity optical systems. We report the performance of polarization multiplexed (or dual-polarization) quadrature phase-shift keying at 40 and 100 Gb/s. Index Terms-Electronic signal processing, optical coherent transceiver, polarization multiplexing, quadrature phase-shift keying (QPSK).

Passive filterless core networks based on advanced modulation and electrical compensation technologies

“…Our proposal, which takes advantage of coherent transmission and electronic dispersion compensation technologies [4,5], is based on the premise that the need for agility can be provided by wavelength tuning at the transmitter and wavelength discrimination at the receiver, in much the same way as agility is achieved in radio networks. The concept of a filterless optical line system is illustrated in Fig.…”

“…1, filterless links are composed of optically amplified fiber spans and passive power splitters/combiners only. It is further assumed that the λ-tunable transceivers at the terminals are equipped with digital signal processing (DSP) modules that can compensate >50,000 ps/nm of chromatic compensation (CD) and more than 100 ps of peak differential group delay due to polarization mode dispersion (PMD) [5]. The filterless network architecture relies on the wavelength selection capability of the coherent receiver to realize the filter function at the drop ports of the nodes.…”

“…The resulting network architecture does not require optically reconfigurable components and colored components, which is why it is called "filterless". Our proposal, which takes advantage of advanced modulation, electronic dispersion compensation, and tunable transceiver technologies, is based on the premise that the need for agility can be provided by wavelength tuning at the transmitter and wavelength discrimination at the receiver, in much the same way as agility is achieved in radio networks [4,5]. Filterless networks essentially offer a passive broadcast medium in which passive optical splitters and combiners are used at some nodes for interconnecting the fiber links.…”

112 Gb/s PM-QPSK transmission systems with reach lengths enabled by optical fibers with ultra-low loss and very large effective area

“…Table 1 summarizes the relative required OSNR for various bit rates and modulation formats, spanning direct detection and coherent detection systems. The relative OSNR values in Table 1 are adapted from Roberts et al 1 and represent theoretical results. The results are referenced to 10 Gb/s ON-OFF keying (OOK) with direct detection.…”

“…Of course span loss is directly related to the fiber attenuation coefficient α dB (dB/km), so reducing α dB reduces span loss and leads to increased OSNR. There is also a connection between nonlinear tolerance and fiber attenuation that is defined by the effective length 2 (L eff ), where L eff is defined as (1) and α is the attenuation in linear units (km -1 ) and L is the span length. This definition of effective length recognizes that for lower attenuation fiber, the signal power does not drop as quickly with distance and so there is a slight reduction in nonlinear tolerance compared to a fiber with similar A eff and n 2 but higher attenuation.…”