公开(公告)号：EP2185968A1

公开(公告)日：2010-05-19

申请号：EP08776081.5

申请日：2008-07-28

申请人： Xtera Communications Limited

发明人： WEBB, Stephen Michael ,  DESBRUSLAIS, Stephen ,  OBERLAND, Richard ,  ELLISON, John

IPC分类号： G02F1/01 ,  H04B10/155

CPC分类号： G02F1/0136 ,  G02F1/0102 ,  G02F1/0147 ,  G02F2201/205 ,  G02F2203/585

摘要： An apparatus and method are provided for filtering an optical signal by wavelength. An initially polarised signal is passed through a DGD element effective to alter the polarisation state of the components of the signal according to wavelength. A polarisation filter (polariser) is then provided to attenuate light having given polarisation states from the signal, thereby attenuating the wavelengths associated with said polarisation states. The invention finds particularly utility in the domain of vestigial sideband filtering, allowing the bandwidth of signals within a wavelength division multiplexed system to be reduced without introducing the deleterious effects associated with conventional wavelength filters.

公开(公告)号：EP2002574A1

公开(公告)日：2008-12-17

申请号：EP07712909.6

申请日：2007-03-15

申请人： Xtera Communications Limited

发明人： DESBRULAIS, Stephen ,  OBERLAND, Richard ,  BARNES, Stuart ,  WEBB, Stephen, Michael

IPC分类号： H04B10/135 ,  H04B10/155 ,  H04J14/02

CPC分类号： G02B6/278 ,  G02B6/274 ,  G02B6/2786 ,  H04B10/2572 ,  H04B10/506

摘要： A device and method for depolarising the total field of a wavelength division multiplexed (WDM) signal is provided. A polarisation maintaining multiplexor combines a plurality of optical signals to form a polarised multiplexed signal. The multiplexed signal is then passed through a differential group delay (DGD) element adapted to modify the polarisation state of one or more optical source signals within the multiplexed signal and thereby to at least partially depolarise the multiplexed signal.