Measuring in-band optical signal-to-noise ratio (OSNR)

摘要

One measurement system comprises a polarimeter with a polarimeter detector bandwidth that partially overlaps with a signal bandwidth or completely overlaps with a signal bandwidth. The polarimeter measures a state of polarization (SOP) or a degree of polarization (DOP) of the signal in the presence of noise. The system further comprises a sampler that receives polarimeter signals from the polarimeter and samples those received signals at a specified sampling rate. The sampler outputs sampled data to a processor that calculates a mean DOP for the samples. Subsequently, the OSNR is determined from the calculated mean DOP.

主权项

1. A system for measuring in-band optical signal-to-noise ratio (OSNR) of signals having a signal electrical bandwidth (BS), the signals being carried in at least two polarization tributaries, the system comprising:
a dual-polarization optical channel (DPOC) to carry the signals; a polarimeter comprising an input and an output, the polarimeter having a polarimeter bandwidth (BP), the BP partially overlapping with the BS, the polarimeter to measure a degree of polarization (DOP) of the signals; a sampler operatively coupled to the output of the polarimeter, the sampler to sample the DOP of the signals at a sampling rate and produce N digitized samples of the measured DOP, the sampling rate being at least 2BP; and a processor operatively coupled to the sampler, the processor comprising:
a DOP sorter to sort the N digitized samples;a mean DOP calculator to calculate mean DOP from M digitized samples, M being less than N; andan OSNR calculator to calculate in-band OSNR as a function of the calculated mean DOP.