SSBI Mitigation and the Kramers–Kronig Scheme in Single-Sideband Direct-Detection Transmission With Receiver-Based Electronic Dispersion Compensation

Abstract

The performance of direct-detection transceivers employing electronic dispersion compensation combined with DSP-based receiver linearization techniques is assessed through experiments on a 4 × 112 Gb/s wavelength-division multiplexing direct-detection single-sideband 16 quadratic-amplitude modulation Nyquist-subcarrier-modulation system operating at a net optical information spectral density of 2.8 b/s/Hz in transmission over standard single mode fiber links of up to 240 km. The experimental results indicate that systems with receiver-based dispersion compensation can achieve similar performance to those utilizing transmitter-based dispersion compensation, provided it is implemented together with an effective digital receiver linearization technique. The use of receiver-based compensation would simplify the operation of a fiber link since knowledge of the link dispersion is not required at the transmitter. The recently proposed Kramers-Kronig receiver scheme was found to be the best performing among the receiver linearization techniques assessed. To the best of our knowledge, this is the first experimental demonstration of the Kramers-Kronig scheme.

Information Capacity of Direct Detection Optical Transmission Systems

“…values of Eqs. (11) and (12) with respect to the transmitted distribution p x (x). In order to derive Eq.…”

“…R ECENTLY, the field of optical communications is witnessing a revival of interest in direct detection receivers, which are often viewed as a promising low-cost alternative to their expensive coherent counterparts [1]- [12]. This process stimulates an interesting fundamental question to whose answer the present paper is dedicated: What is the difference between the information capacity of a direct detection system and that of a system using coherent detection?…”

DSP for Single-sideband Direct-detection Systems

“…Conventional homodyne and heterodyne coherent designs were modeled to provide benchmark performance, whilst single-photodiode receiver with sufficiently wide guard-band to avoid SSBI [2] and digital SSBI mitigation schemes, including single-stage [3] and two-stage [4] linearization filters and KramersKronig (KK) scheme [5][6][7] were assessed for DD systems. Penalties due to the practical limitations were neglected, allowing to purely focus on performance differences between the SSBI mitigation schemes.…”

Carrier-assisted differential detection

“…After square-law detection using a single-ended photodiode (PD), signals can be extracted from the signal-carrier beating term, and the optical field is reconstructed without using a local oscillator. In the recent decade, various schemes of field recovery with direct detection have been investigated [12][13][14][15][16][17][18][19][20][21][22][23] . Since direct detection generally provides only intensity information, until now, signals have been mainly restricted to the single sideband (SSB) modulation format in various proposed intensity-only detection schemes 14 .…”

“…To mitigate SSBI, a frequency gap, which is commonly as wide as the signal bandwidth, can be placed between the carrier and signals 15 . To overcome the poor SE of the above approach, a self-coherent scheme without a frequency gap has been proposed in which SSBI can be estimated and then subtracted in an iterative manner [16][17][18] . In recent years, the Kramers−Kronig (KK) receiver has been proposed to effectively mitigate SSBI without using iterations 19 .…”