Low jittered optical pulse generation from a gain-switched single-mode VCSEL with an external laser beam injection

We report experimental results on timing-jitter suppressed optical short pulse generation from a gain-switched single-mode vertical-cavity surface-emitting laser (VCSEL) at 1.55 μm wavelength with an external laser beam injection. The low timing-jittered optical short pulses are very useful for high-speed optical time-division-multiplexed (TDM) communications and signal processing. The obtained timing jitter and pulse duration from the VCSEL were less than 1 ps and 65 ps, respectively, at a pulse repetition rate of 1.6 GHz.

1 Introduction

The low timing-jittered optical short pulse source at variable repetition rate is an essential element in high-speed optical TDM communication systems and high-speed optical signal processing schemes [1]. The gain-switching operation of laser diodes is a very useful method for generation of short optical pulses with a relatively high peak power [2]. Since the VCSELs have superior characteristics of low power consumption, a low loss fiber coupling, and low cost packaging capability compared to the edge-emitting lasers, low-timing jittered optical pulses generated from the VCSELs can be effectively used in high-speed OTDM long-distance optical communication systems. However, the gain-switching scheme inherently contains a significant timing jitter in the optical pulse generation, which results in a major limiting factor for such system applications. In this paper, we report timing-jitter suppressed optical short pulse generation from a gain-switched VCSEL at wavelength with an external optical beam injection. The timing jitter of the gain-switched pulses was reduced up to 89% under the beam injection compared to that of a free running VCSEL without any optical output power penalty.