Optical fiber stretching technique for the precision time delay in ultrahigh speed OTDM system

A new technique for permanent and accurate optical fiber length adjustment is described. This technique is based on pulling an optical fiber in a computer controlled fusion splicer. To demonstrate its subpicosecond accuracy and loss less than 0.1 dB per stretching a feed-forward time delay unit generating 64 pulses that are separated 10 ps apart was constructed and fine tuned the tetrahertz optical asymmetric demultiplexer switching window by 2.5 ps. This technique was also successfully applied to low stress PM fiber. Fiber stretching of 200 μm only 0.2 dB of loss and less than -20 dB of polarization crosstalk.