System and method for monitoring optical performance in a spatial division multiplexing system

A spatial division multiplexing (SDM) based optical communication system comprising:

• a plurality of communication lanes, each communication lane comprising:
• a plurality of transmitters configured to modulate a plurality of optical signals with distinguishable pilot tone (PT) signals;
• a multiplexer configured to multiplex the plurality of modulated optical signals;
• an optical fiber configured to carry the multiplexed modulated optical signals;
• an optical coupler coupled to the optical fiber of each communication lane and configured to:
• extract at least a portion of the multiplexed modulated optical signals propagating in each communication lane;
• combine the extracted portion of the multiplexed modulated optical signals, and generate a combined optical signal;
• and
• a pilot tone detector (PTD) configured to extract PT signals from the combined optical signal, determine optical signal specific information included in the PT signals, and compute optical power of each optical signal based on the optical signal specific information.

A method for monitoring optical performance in a spatial division multiplexing (SDM)-based optical communication system, comprising:

• extracting, by an optical coupler, at least a portion of a plurality optical signals propagating in different communication lanes of the SDM-based optical communication system, wherein each optical signal of the plurality of optical signals is modulated with a distinguishable pilot tone (PT) signal;
• combining, by the optical coupler, the extracted portion of the plurality of optical signals, and generate a combined optical signal;
• extracting, by a pilot tone detector (PTD), PT signals from the combined optical signal;
• determining, by the PTD, optical signal specific information included in the PT signals;
• and
• computing, by the PTD, optical power of each optical signal based on the optical signal specific information.