T. van Dongen

Transmission of 8 DWDM channels at 20 Gb/s over 160 km of standard fiber using a cascade of semiconductor optical amplifiers

Eight DWDM channels in the wavelength region 1558-1570 nm, spaced at 200 GHz, are modulated at 20 Gb/s and transmitted over 160 km of SSMF (four 40-km spans) using four in-line SOAs. Transmitter booster-amplifiers and receiver preamplifiers are also SOAs, Q-factors better than 17 dB, corresponding to a BER of less than 3/spl middot/10/sup -13/, have been measured for all channels.

8 x 10 Gb/s DWDM transmission over 240 km of standard fiber using a cascade of semiconductor optical amplifiers

Eight 10-Gb/s DWDM channels spaced 200 GHz around 1565 nm are transmitted over six 40-km spans of standard SMF using five inline semiconductor optical amplifiers (SOAs). SOAs are also used as booster and pre-amplifier in the transmitter and receiver, so that only SOAs are used in the experiment. For all channels, bit-error-rate penalties of 0.5-1.5 dB relative to baseline have been measured, with no evidence of error-rate floors.

Monolithically integrated 80-gb/s AWG-based all-optical wavelength converter

We present a monolithically integrated all-optical wavelength converter. The converter consists of four semiconductor optical amplifiers for four separate inputs and an arrayed-waveguide grating. Error-free wavelength conversion with reasonable penalties for a 27 -1 pseudorandom binary sequence was shown for a single input 80-Gb/s signal. The device exploits cross-gain/phase modulation in a single amplifier and selects with a filter the blue-chirped spectrum of the new wavelength signal in order to speed up the device response. This device has a dimension of 1.7times3.5 mm2 and it can be operated to convert simultaneously four 80-Gb/s wavelength channels

High-gain 1310 nm semiconductor optical amplifier modules with a built-in amplified signal monitor for optical gain control

A compact high-gain 1310-nm semiconductor optical amplifier (SOA) module incorporating two photodiodes to detect radiation emitted from the two opposite facets of the amplifier chip is reported. By subtracting their signals, a measure of the amplified signal is obtained without the need for optical filtering, Using this, amplified signals can be stabilized within 0.5 dB over a 25-dB range of input signals.

An integrated coupled-cavity 16-wavelength digitally tunable laser

We present a digitally tunable laser that was realized by coupling two wavelength periodical four-channel lasers. The lasers were coupled with a multimode interference coupler, in such a way that the device has a common intracavity output waveguide containing the full multiplexed signal. In the two laser cavities, 1 /spl times/ 4 PHASARs were used with a channel spacing of 100 and 400 GHz, respectively. By coupling each PHASAR to four semiconductor optical amplifiers, 4 /spl times/ 4 channels were generated. The measured SMSR for each of the 16 wavelengths is better than 40 dB.

Loss reduction for phased-array demultiplexers using a double etch technique

Wavelength Division Multiplexing (WDM) is an effective technique to exploit the huge bandwidth of optical fibres. Key components in such WDM-systems are demultiplexers which spatially separate the different wavelength channels. Phased-array demultiplexers combine ease of fabrication and low insertion losses. Silica-based phased-array demultiplexers are realised with low losses from 2-3 dB [1,2]. InP-based demultiplexers show slightly higher on-chip losses of 4-6 dB [3,4]. In addition they have considerably higher fibre coupling losses (several dB’s), but the advantage of InP-based demultiplexers is that they can be integrated with active components. Earlier we reported a low-loss demultiplexer with reduced fibre coupling loss by applying deeply etched InGaAsP waveguides with a relatively large core and a low index contrast, which had an almost circular mode profile [5]. The component had 4-5 dB on-chip loss and fibre coupling loss of about 1 dB to a tapered fibre. In this article we report a method to further reduce the on-chip losses.

High-gain 1310-nm reflective semiconductor optical amplifiers with low-gain uncertainty

A 1310-nm reflective semiconductor optical amplifier with a gain uncertainty of only 0.8 dB at an average gain level of over 30 dB has been demonstrated using a microoptic polarization reversing retroreflector. For this amplifier 3-dB saturation output powers of up to 10 dBm and a noise figure of 7.5 dB have been obtained. A low gain uncertainty for undefined input signal polarization states and input signal wavelengths (which may vary over several nanometers) is of primary importance in switching applications.

Large Bandwidth Polarisation Independent and Compact 8 Channel PHASAR Demultiplexer/Filter

The first broadband polarisation independent Phasar based demultiplexer/filter is demonstrated employing non-birefringent InGaAsP(λg = 0.97 μm)-on-InP raised strip waveguides. The device exhibits a channel spacing of 2 nm, on-chip loss of 4-5 dB, a cross talk better than -25 dB and a 3 dB channel bandwidth of 0.9 nm. The Phasar size is 2.6×2.3 mm2. The fibre-chip-coupling loss is less than 1 dB.

Universality of the chirp-parameter of bulk active electro absorption modulators

The universal behavior of chirp-parameter, modulation efficiency, output power and photocurrent of bulk active electro absorption modulators is experimentally and theoretically demonstrated the voltage over the EAM is scaled with an EAM threshold field.

An all-optical wavelength converter in a layer-stack suitable for compact photonic integration

An apparatus for determining the direction of ambient airflow and a method for the use thereof. The apparatus includes man-made or natural fibers that float when released into the air by a user. The direction of ambient airflow is determined by observing the direction of movement of the fibers from the point of release from the users hand.