Contents Introduction
A 160-Gbit/s optical time-division multiplexing (OTDM) system is an attractive solution for future high-bit-rate fiber transmission systems [1]. In this scheme, demultiplexing requires the recovery of an optical clock at the reduced data rate. To effectively recover a fast optical clock, we have developed an optical clock recovery device that uses a regeneratively mode-locked laser diode (MLLD-OCR), and demonstrated successful recovery of a 40-GHz optical clock from a 160-Gbit/s data stream [2]. In this device, the operating frequency of the MLLD (~40 GHz) was locked with the injection of the optical pulses at the harmonic frequency (160 GHz). However, locking mechanism is not well understood at present. In this work, we experimentally investigated the locking mechanism with the aim of improving its efficiency.
