This paper addresses OFDM transmission over optical links with high spectral efficiency, i.e. by using high-order QAM-modulation schemes as a mapping method prior to the OFDM multicarrier representation. Low and moderate cost optics which is mandatory in access and in metro applications is assumed. Here we address especially direct detection receivers using… (More)
For chip-design of a frequency-domain equalizer, a simple procedure to minimize the number of multiplications is shown. Considerations include recent improvements of FFT-algorithms.
We demonstrate the first OFDMA uplink transmission with four individually modulated ONUs with central distribution of the optical carrier and coherent reception at the OLT, showing that OFDMA-PON is viable.
We experimentally determine the required OSNR and dispersion tolerance of RZ-8DPSK at 32.1Gb/s. We show a 1dB dispersion tolerance of 600ps/nm and an OSNR penalty of 6.7dB compared to RZ-DQPSK at the same symbol rate. Introduction: It is well known that the advanced return to zero (RZ) optical differential quadrature phase shift keying (DQPSK) modulation is… (More)
—Orthogonal Frequency Division Multiplexing (OFDM) is an established technique for equalization of the dispersion-dominated fiber-optical channel. The dispersive nature of the optical channel results in a frequency selective equivalent channel if double sideband (DSB) intensity modulation (IM) and direct detection (DD) is employed. In order to maintain the… (More)
In high bitrate optical transmission systems the dynamic changes of the transmission channel easily exceed the system tolerances for an error free operation. To meet the tolerances an adaptive equalizer is necessary. We demonstrate the capabilities of planar lightwave circuit integrated optical FIR-filters for an adaptive compensation of optical fiber… (More)
We investigate the performance of a combined Tomlinson-Harashima precoding (THP) and a Volterra nonlinear equalization (VNLE) in a nonlinear fiber-optic communication system aiming at a data rate of 100 Gbits/sec. THP-VNLE is compared with a feed-forward VNLE and a combined VNLE decision-feedback equalizer (DFE) by means of performance and computational… (More)
Transmitter and receiver nonlinearity are compensated for by means of an iterative decision feedback algorithm. The sensitivity for 100 Gb/s direct detected OFDM without frequency gap is improved by approximately 6 dB.