Carrierless amplitude phase modulation of VCSEL with 4 bit/s/Hz spectral efficiency for use in WDM-PON

Abstract

We experimentally demonstrate successful performance of VCSEL-based WDM link supporting advanced 16-level carrierless amplitude/phase modulation up to 1.25 Gbps, over 26 km SSMF with spectral efficiency of 4 bit/s/Hz for application in high capacity PONs.

A Multi-CAP Visible-Light Communications System With 4.85-b/s/Hz Spectral Efficiency

“…The m-CAP signals optimized with the appropriate number of bits-per-symbol-per-subcarrier are subsequently loaded into the TTI TGA12104 and the same routine occurs. There have been reports of equalization in the literature before de-mapping from the M m -QAM constellation, including the use of analogue [10] and digital [22] frequency domain equalizers, the constant multi-modulus [17], [23], least mean squares [24] and k-means [15] algorithms and decision feedback equalization [25], [26], 26]. In this work we do not consider an equalizer because we would like to demonstrate the raw improvement in spectral efficiency with increasing order of m. Further, in an m-CAP system with a high m, an individual equalizer would be required for every subcarrier, drastically increasing the computational complexity and surrendering some of the advantages of CAP over OFDM and single-carrier QAM systems.…”

Experimental demonstration of optical data links using a hybrid CAP/QAM modulation scheme

“…Power efficient communication systems are, therefore, critical for future internet networks. In response to this issue, several promising modulation techniques, including pulse amplitude modulation (PAM) [1][2][3], carrierless amplitude/phase (CAP) modulation [2][3][4][5][6], and optical orthogonal frequency division multiplexing (OFDM) [2,5] have been investigated and compared to identify cost efficient and power efficient solutions for scenarios, such as data center optical interconnects [5] and single-laser 100 gigabit ethernet links [1][2][3]7].…”

Multi-band carrier-less amplitude and phase modulation for bandlimited visible light communications systems

“…It should be noted that m = 20 corresponds to 40 FIR filters in the transmitter alone, and a further 40 in the receiver, amongst other resources. Therefore, the length of the filters is crucial; and hence studies have been performed that investigate the effect on varying lengths [13] and demonstrate improved BER performance with longer filter lengths. Depending on system requirements such as the target bit rate, BER or application, amongst others, forty FIR filters could be considered excessive, depending on the available resources.…”