A novel integrated optical planar waveguide platform for
absorption-based biosensing is demonstrated. The platform integrates surface ion-exchanged channel waveguides with one-step UV patterned sol-gel structures to define the probing regions. Cytochrome c protein was utilized to characterize the device performance. Spectroscopically specific attenuation of approximately 2 dB in the guided signal occurred at 532nm for 1.4 cm long probing region. The estimated level of detection is about 1 pmol/cm<sup>2</sup> of surface adsorbed cytochrome c. The proposed structure enables environmentally stable, compact, and inexpensive sensing devices that can be applied to a wide range of biological and chemical species.
Current WDM Systems in optical networks are commonly operated at 2.5 and 10 Gbit/s per wavelength. First transmission systems, offering the possibility of using 40 Gbit/s/λ transponders, are now commercially available. Transaction of various field trials over the last years indicates remarkable interest for this systems among the network operators. Potential further stages of systems at higher channel data rates e.g. 80, 100 or 160 Gbit/s/λ thus attracted more and more attention in the R&D community. Existing concepts like broadband dispersion compensation, distributed Raman amplification, bandwidth efficient and impairment tolerant modulation formats have been applied, but also new circumstances and physical impairments have to be considered, which are negligible at lower data rates. For data rates above 40 Gbit/s chromatic dispersion causes pulses to broaden extremely rapidly, so that transmission behaviour can be regarded as "quasi-linear". We will present a comprehensive overview to what extend system reach limits can be stressed for 160 Gbit/s/λ data rates when different parameters such as fiber type (standard single-mode fiber SMF and non-zero dispersion fiber NZDSF), modulation format (return to zero RZ, carrier suppressed return to zero CS-RZ, intensity modulated differential phase shift keying IM DPSK), different dispersion compensation schemes and signal power levels are optimized. Further, the benefit from using balanced instead of single ended receiver is investigated for IM DPSK.
With increasing line rates system tolerances due to both, chromatic dispersion and dispersion slope, become more restrictive. By means of numerical simulations we investigate the influence of temperature fluctuations in cascaded multi-section dispersion-compensated standard single-mode fiber SMF based transmission systems. Eye opening penalty (EOP) for different modulation formats - non-return-to-zero NRZ as well as return-to-zero RZ with duty cycles varying from 0.2 to 0.6 and for different signal power levels varying from -9 to +3 dBm at a line rate of 160 Gbit/s are calculated. Performance degradation due to temperature-induced dispersion variations is investigated for three different scenarios: a) the temperature of the installed terrestrial fiber-optic cable changes, b) the temperature of the temperature-controlled indoor dispersion compensating module DCM changes, c) combined effects.