I am so grateful for your quick answers.
Actually we are carrying out a research on optical network technology called Optical Burst Switched (OBS), one of its features is the data link is not continuous but swiched all the time. for example, there are 3 nodes in an network, called A, B, C. node B and C is connected to node A through a optical switch. the optical switch will continuous change the optical path between A-B and A-C according the setup message, so it is inevitable to relock the data frequence when optical path changed.
therefore the recovery time is essential for our design, I don't know if it is fixed or can be estimated by some method, it will be very helpful if you can share us some material about this parameter.
Many Thanks,
Liming