Abstract: A mode-mixer is used to introduce mode-mixing to an input in an optical coupler. As a result, modal noise effects are minimized in an output of the optical coupler. An example of a mode-mixer implemented includes a step index optical fiber which may or may not be coupled to a graded index optical fiber via a splice within an optical coupler. The splice may be a mechanical splice using connectors or a fused splice in some embodiments. The optical coupler may be included in a system for monitoring and/or analyzing a network.