Abstract
We propose and experimentally demonstrate a distance-adaptive bandwidth allocation scheme to realize high-capacity long-reach orthogonal frequency division multiple access passive optical network (OFDMA PON) with cost-effective electro-absorption modulator (EAM). In our scheme, the subcarriers in downstream OFDM signal are properly allocated to the optical network units (ONUs) with different fiber transmission lengths. By this means, the detrimental influence of power fading induced by dispersion and chirp can be avoided, thus all OFDM subcarriers can be modulated with high-order quadrature amplitude modulation (QAM) format, leading to a high transmission capacity. A proof-of-concept experiment is performed, in which three ONUs with transmission distances of 25, 50, and 100 km are assigned with different subcarriers, respectively. By using distance-adaptive bandwidth allocation technique, an OFDM signal of 34.5 Gb/s is successfully delivered to the ONUs with a bit error ratio (BER) lower than 2 × 10(-3).
Highlights
Driven by the exponentially increasing customer demands for broadband services, passive optical network (PON) has emerged as a promising candidate to economically provide high bandwidth to end-users [1,2]
Multiple schemes, such as time division multiplexing (TDM) [5], wavelength division multiplexing (WDM) [7], and orthogonal frequency division multiplexing (OFDM) [8,9,10,11,12], have been used in the long-reach PON to support a large number of customers with a broad coverage
At the optical line terminal (OLT), a continuous wave (CW) light from a tunable laser at 1550 nm is fed into a 10-GHz electro-absorption modulator (EAM), which is driven by an electrical OFDM signal
Summary
Driven by the exponentially increasing customer demands for broadband services, passive optical network (PON) has emerged as a promising candidate to economically provide high bandwidth to end-users [1,2]. The hierarchies of optical network can be greatly simplified by the long-reach PON, reducing network latency and benefiting real-time broadband services Multiple schemes, such as time division multiplexing (TDM) [5], wavelength division multiplexing (WDM) [7], and orthogonal frequency division multiplexing (OFDM) [8,9,10,11,12], have been used in the long-reach PON to support a large number of customers with a broad coverage. Suppressing one sideband of the DSB signal with a dual EML scheme is a way to minimize the influence of power fading [17,18] These schemes are relatively expensive and complex to be implemented in practical access networks. Compared to the previous works, our proposal exhibits the advantages of low cost, easy implementation, and low complexity
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