A. Buxens

Comparison of all-optical co- and counter-propagating high-speed signal processing in SOA-based Mach–Zehnder interferometers

The all-optical signal processing performance of a Mach–Zehnder interferometer (MZI) is investigated. Calculated switching windows are used to investigate and understand the physical mechanisms limiting the high speed performance. Especially, the co- and counter-propagating operation of the MZI is discussed and important differences in the performance for the two schemes are addressed. The non-regenerative all-optical clear and drop functionality is investigated for a 2, 4 and 8 × 40 Gbit/s signal, showing good performance in the co-propagating case. Regenerative simultaneous clear and drop functionality in a single MZI is demonstrated experimentally and compared to the large signal model predictions.

Bidirectional four-wave mixing in semiconductor optical amplifiers: theory and experiment

Bidirectional four wave mixing (FWM) is investigated in a bulk semiconductor optical amplifier (SOA) for dispersion compensation and for the clear/drop functionality in optical time division multiplexed (OTDM) systems. Good performance for bidirectional midspan spectral inversion (MSSI) is theoretically predicted for bit rates of 10, 20, and 40 Gb/s and is shown to be in agreement with measurements performed at 10 and 20 Gb/s. Measurements of the clear/drop functionality using the bidirectional technique show excellent performance for a 4/spl times/10 Gb/s signal and is again in good agreement with simulations. The clear/drop functionality is also simulated for 4/spl times/20 Gb/s and 4/spl times/40 Gb/s signals.

Investigation of cascadability of add-drop multiplexers in OTDM systems

The influence of coherent cross-talk on the cascadability of add-drop multiplexers in optical time division multiplexing (OTDM) systems is analysed theoretically using moment generating functions. Calculations are validated by experiments.

Simultaneous realization wavelength conversion and signal regeneration using a nonlinear optical loop mirror

Wavelength conversion and signal regeneration are realized simultaneously by employing a nonlinear optical loop mirror (NOLM). The experiments demonstrate that the NOLM has strong regenerative capability when it is used as wavelength conversion media. Proper choice of the initial state of the polarization controller in the NOLM can enhance the extinction ratio of the converted signal.

Ultrafast all-optical demultiplexer based on monolithic Mach–Zehnder interferometer with integrated semiconductor optical amplifiers

A monolithically integrated and fully packaged Mach–Zehnder interferometer with semiconductor optical amplifiers (MZI-SOA) is demonstrated as polarisation-independent high-speed demultiplexer for up to 160 Gbit/s optical time division multiplexed (OTDM) data streams.

All-optical regenerative OTDM add/drop multiplexing at 40 Gbit/s using monolithic InP Mach-Zehnder interferometer

Summary form only given. Add-drop time multiplexing is a necessary function required in an optical time-division multiplexed (OTDM) network node. Perfect clearing of the time slot which corresponds to the drop channel should be performed in order to avoid interferometric crosstalk. Simultaneous add-drop multiplexing using a semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer (MZI) has been previously performed. However the performance was limited by pattern effects after clearing and the compromise between either perfect clearing or dropping. We present a novel method which allows for simultaneous perfect dropping and clearing for 40 Gb/s OTDM signals using a monolithically integrated SOA-MZI. Further the proposed technique introduces regenerative capabilities at each add-drop node avoiding the cascadability limitation of OTDM add-drop nodes.

40 to 10 Gbit/s demultiplexing using a self-pulsating DFB laser for clock recovery

A self-pulsating DFB laser has been used as the clock recovery unit in an OTDM demultiplexing system experiment. Error free demultiplexing from 40 Gb/s to 10 Gb/s is achieved.

Efficient and robust regenerative all-optical wavelength converter for Cand L-band (80 nm span) and for data rates up to 40 Gbit/s

Summary form only given.Wavelength division multiplexed (WDM) networks will need optical wavelength converters in optical cross connects to avoid wavelength blocking when routing the signals. Interferometric devices have regenerative capabilities and are therefore of special interest to guarantee cascadibility. We present a monolithically integrated Mach-Zehnder interferometer with semiconductor optical amplifiers (MZI-SOA) that demonstrates efficient all-optical 2R regenerative 10 Gbit/s wavelength conversion over the full C- and L-band with a negative penalty of about -1 dB. The converted output signals have an optical signal-to-noise ratio (OSNR) better than 45 dB. All-optical 2R and 3R regenerative wavelength conversion at 40 Gbit/s within the entire C-band has been already reported using the same kind of device. We show that the device has the capability for regenerative wavelength conversion at 40 Gbit/s even in and beyond the L-band.

Wavelength conversion from C- to L-band at 10 Gbit/s including transmission over 80 km of SSMF

Summary form only given.As the need for capacity increases, means to accommodate the growth is getting increasingly important. Hence, higher bit rates and an ever increasing number of WDM channels is being employed. This has led to the introduction of the L-band (ranging from 1570 to 1610 nm) as the new transmission window, opening up for-in conjunction with the C-band-an astonishing 80 nm of available bandwidth. However, as the number of wavelength channels increases, the need for wavelength conversion is becoming ever more pronounced. To perform the wavelength conversion, interferometric structures such as the monolithically integrated Mach-Zehnder interferometers (SOA-MZI) using semiconductor optical amplifiers as phase-shifting elements have proven excellent candidates. Here we present the conversion and transmission properties of a fully packaged device capable of wavelength conversion from C- to L-band having more than 80 nm of wavelength conversion range.