A Novel CAP-WDM-PON Employing Multi-Band DFT-Spread DMT Signals Based on Optical Hilbert-Transformed SSB Modulation

Abstract

We propose and experimentally demonstrate a novel carrier-less amplitude/phase modulation wavelength-division-multiplexing passive optical network (CAP-WDM-PON) with its bandwidth efficiency enhanced by using a multi-band discrete Fourier transform spread (DFT-spread) discrete multi-tone (DMT) signal based on Hilbert-transformed single-sideband (HB-SSB) modulation. The DFT-spread technique is utilized to extend orthogonal subcarriers, which effectively restrain the high-peak signal formation probability, and thereby, it can significantly reduce the high peak-to-average power ratio of the DMT signal. The proposed optical line terminal (OLT) in CAP-WDM-PON suggests five downlink optical subcarriers. For each optical subcarrier, there are as many as 6 × 20 Gb/s SSB digital DMT channels CAP modulated on them, which can be efficiently generated by using only one set of optical transmitter hardware. The experimental results show that the proposed system is capable of accommodating 5 × 6 channels (20 Gb/s per channel) within an optical distribution network (ODN) loss budget of 19.4 dB, and there is a 2.4-dB ODN loss budget improvement by utilizing the DFT-spread scheme. More importantly, the proposed spectraland bandwidth-efficient CAP-WDM-PON system requires six times less downlink optical transmitters at the OLT, which can be translated into savings in cost, power consumption, and footprint. In addition, key techniques, such as pre-equalization for high-frequency components and digital HB-SSB modulation format for generation of multi-band DMT signals, are also studied.

Multi Wings Chaotic Encryption Scheme for PAM-DMT-Based Optical Access Network

“…M-ary quadrature amplitude modulation (M-QAM) orthogonal frequency division multiplexing (OFDM) has attracted great interest in optical wireless access networks because of its high spectrum efficiency and flexible bandwidth allocation [1][2]. As a modification of quadrature amplitude modulation OFDM (QAM-OFDM), pulse-amplitude-modulated discrete multitone (PAM-DMT) was introduced in various intensity modulated/direct detection (IM/DD) access systems such as single-mode fiber, multimode fiber, and optical wireless system to achieve real signal [3][4][5][6][7][8]. Compared with direct current (DC) biased optical OFDM (DCO-OFDM) that adds a DC bias to the original bipolar OFDM signal [9], asymmetrically clipped optical OFDM (ACO-OFDM) that only modulates the odd subcarriers [10], PAM-DMT loads information onto the imaginary (or quadrature) parts of all subcarriers.…”

50 Gb/s Transmission using OSSB-MultiCAP Modulation and a Polarization Independent Coherent Receiver For Next-Generation Passive Optical Access Networks

“…This distance is even shorter for higher bandwidths as the ones needed for 50 Gb/s PAM4 based architectures. This problem can be avoided using full coherent reception or Optical Single Sideband (OSSB) modulation as proposed in [10,11], although they usually present low sensitivities. There has also been interest in the use of Krammers-Kronig receivers [12] as a mean to obtain a native Single Sideband (SSB) modulation and reception, but many of them use multicarrier modulation schemes and require a high Carrier to Signal Power Ratio (CSPR) [13].…”

Zero Guard Band Multi-Twin-SSB System in Single Fiber Bidirectional PON Transmission

“…The multi-CAP technique can reach high data rate by using different modulation formats and components with limited bandwidth and less complexity. Hence, the CAP modulation with multiband has been considered as a promising low cost solution for the multiple-user PON systems and has attracted extensive investigations [18]- [21]. In 2013, Miguel Iglesias et al experimentally demonstrated 102 Gbps transmission over 15 km fiber with 6 sub-bands multi-CAP [18].…”

“…In the same year, Junwen Zhang et al verified a wavelength division multiplexing (WDM) CAP-PON architecture based on multi-CAP 16-QAM with 5 sub-bands [19]. In 2019, Youxu Zen et al successfully demonstrated a 6 sub-bands CAP-WDM-PON scheme with 5 wavelengths over 20 km fiber transmission based on the discrete multi-tone (DMT) and Hilbert transformed single sideband (SSB) modulation [21]. In brief, the multi-CAP technique can provide large capacity with the flexibility and elasticity of the modulation formats.…”