Abstract

As data rates move from 10 to 40 Gb/s, semiconductor-based all-optical signal processing techniques are reaching their fundamental speed limit. Due to their versatility and ultrafast (fs) response, fibre Nonlinear Optical Loop Mirrors (NOLMs) [1] have the potential to achieve major functions in future high bit rate links. An improved version of the device, more stable and flexible than the conventional designs, based on Nonlinear Polarisation Rotation (NPR), was proposed in [2]. It includes a power-symmetric coupler, a quarter-wave plate (QWP) and a span of highly twisted standard fibre. With this setup, key parameters like the dynamic range of the transmission characteristic or the switching power are readily adjusted through the QWP angle and the input polarisation orientation. In this paper we discuss the enhanced possibilities offered by this device when a single polarisation component is selected at its output (Fig. 1(a)). Applications include all-optical signal processing, regeneration, and self-starting passive mode locking of fibre lasers.

© 2007 IEEE