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)
An 8-bit 100-GS/s digital-to-analog converter (DAC) using a distributed output topology in 28-nm low-power CMOS for optical communications is presented. The DAC can convert 1-k symbols stored in the 1-kbyte design-for-test on-chip memory cyclically. By interleaving four 25-GS/s return-to-zero DACs, the highest signal frequency of the 100-GS/s DAC is about… (More)
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.
The orthogonal frequency division multiple access (OFDMA)-based passive optical network (PON) is a potential candidate to meet the flexibility requirements for next-generation optical access networks. We propose an OFDMA-based PON with a transmission employing intensity modulation/direct detection in the downstream and a remodulation of a remotely seeded… (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.
Using optical phase conjugation with a polarization independent periodically-poled lithium-niobate subsystem, we demonstrate dense WDM 2x10Gbit/s RZ-DQPSK transmission over 10,200km of SSMF with a record accumulated dispersion, exceeding 80,000ps/nm.
We report a patient who had episodes of recurrent peripheral nerve pressure palsies. Electrodiagnostically, we found a clear decrease of nerve conduction velocity in affected and unaffected nerves. All the patient's relatives showed entirely normal clinical and electrodiagnostic findings. Histopathologically, there were extensive irregularities of the… (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)