Optical Filter-Based Mitigation of Group Delay Ripple- and PMD-Related Penalties for High-Capacity Metro Networks

Modified downhill simplex method for fast adaption of optical filters in optical communication systems

“…The random symbol sequence and the noise differ in each evaluation of e CM . The simulated equaliser was realised by combining optical FIR filters in a butterfly structure [3] with 3, 5 and 7 taps per filter corresponding to 12, 20 and 28 DOF per polarisation channel. The free spectral range of the filters was 64 GHz.…”

“…There are several studies in which adaptive optical filters are investigated in the context of channel equalisation [3,4]. The focus of most of these studies is on showing that optical filters can effectively compensate linear channel impairments.…”

“…Hence, more general optimisation strategies have to be considered. Methods like particle swarm optimisation [4] or the Levenberg-Marquardt [3] algorithm have been proposed for the initialisation and the control. Though global optimisation methods are problematic for the control and local methods have the drawback that they need evaluations of the optimisation criterion at different states of the filter to approximate a Jacobian matrix or a gradient in each iteration.…”

Fiber Bragg Grating Technology for New Generation Optical Access Systems

“…DGD and PMD value increases at the edges of the optical filter amplitude transfer function which could be a degradation factor for optical signal transmitted through device [25]. Therefore the relative bandwidth available to each broadband access systems channel is reduced, meaning that the channel experiences the effect of the edge of the pass-band of the filter transfer function, where the dispersion effects is expected to be most significant [17].…”

Efficient bandwidth of 50 GHz fiber Bragg grating for new-generation optical access

“…DGD and PMD value increases at the edges of the optical filter amplitude transfer function which could be a degradation factor for optical signal transmitted through device [15]. Therefore the relative bandwidth available to each broadband access systems channel is reduced, meaning that the channel experiences the effect of the edge of the pass-band of the filter transfer function, where the dispersion effects is expected to be most significant [7].…”