Morten Nissov

Pump interactions in a 100-nm bandwidth Raman amplifier

A design for a 100-nm bandwidth Raman amplifier is presented. The amplifier is pumped with eight, 130-mW lasers with wavelengths ranging from 1416 to 1502 nm. The peak-to-peak gain ripple is 1.1 dB. A new model was developed for this design that includes pump-to-pump and signal-to-signal interactions in addition to double Rayleigh scattering and amplified spontaneous emission. An understanding of the interactions among these various effects was essential to this design. These modeling results are based on measurements of the physical characteristics of the transmission fiber.

Detailed analysis of Raman amplifiers for long haul transmission

Summary form only given. A comprehensive and accurate model of a Raman amplifier has been proposed. The model is based on measured spectra of the Raman gain coefficient and the fiber attenuation. The model includes a complete spectral ASE power distribution, temperature dependence, and Rayleigh scattering. A comparison between measured and calculated gain and noise performance shows agreement better than 0.1 dB. This model has been used to design the Raman amplifiers used in an error-free trans-Atlantic distance 10/spl times/10 Gbit/s wavelength-division multiplexed loop experiment.

Performance improvement in high capacity, ultra-long distance, WDM systems using forward error correction codes

We present a performance study of a forward error correction (FEC) code using theoretical models, Monte-Carlo computer simulations, and a long-haul WDM transmission experiment. With a 14% redundancy code, the Q-factor was increased by 6.2 dB for both linear and non-linear impairments.

Penalty-free transmission at 10 Gbit/s through 40 cascaded 1-nm arrayed waveguide multiplexers

Cascaded optical add-drop multiplexers (OADM) and optical cross connects (OXC) are key components in optical wavelength-division multiplex networks. OADMs with filtering of the passing signals and OXCs can be constructed by the use of wavelength-division multiplexers. Cascadability of multiplexers is therefore vital for the network performance. The actual transfer function of multiplexers is important, because the available end-to-end bandwidth between connected nodes in optical networks with cascades of OXCs and OADMs is given by the product of the transfer functions. In this paper, we demonstrate the cascadability of arrayed waveguide (AWG) multiplexers in a recirculating loop experiment at 10 Gbit/s and show that up to 40 multiplexers each with a 3-dB bandwidth of 1 nm and sharp roll-off characteristics can be passed penalty free.

Accurate measurements of erbium-doped fiber amplifier gain spectra

We show that a wide-band noise source can be used to accurately measure the large-signal gain spectrum of an EDFA. Even in a range where spectral hole burning has a significant impact. Data is presented for a comparison of our technique, with the more conventional method.

Fiber-distributed feedback lasers for high-speed wavelength-division multiplexed networks

Summary form only given. In conclusion, we have demonstrated that fiber DFB lasers constitute an excellent alternative to commercially available semiconductor DFB lasers. We have also shown that two fiber DFB lasers can be spliced together without any BER power penalty. Therefore, we suggest the possibility of using a single pump source for pumping a WDM laser array consisting of a number of fiber lasers spliced in series.