Abstract

High-speed clock recovery or clock synchronization is an important function in realizing future 100 Gb/s time division multiplexed (TDM) communication systems. Optical clock recovery techniques are attractive because they can accommodate bit rates in excess of those allowed by electronics. To date, a number of optical clock recovery and synchronization schemes have been demonstrated including injection-locking diode [1] and fiber [2] lasers. Also, optical phase lock loops have been demonstrated using nonlinear crosscorrelation of two pulse streams as a bit phase sensor. Such schemes have included four wave mixing [3] and gain modulation [4] in diode amplifiers and second harmonic generation in a LiIO₃ crystal [5]. In this paper, we demonstrate all-optical bit phase comparison using a nonlinear optical loop mirror. In addition, we show that a harmonically modelocked external cavity laser can be synchronized to a 40 GHz pulse train generated using soliton compression of a Mach-Zehnder modulator output[6].

© 1995 Optical Society of America