Abstract

The knowledge and control of the pulse timing jitter (TJ) of passively mode-locked (PML) semiconductor lasers (SCLs) is critical for applications such as clock distribution networks and ultrafast optical sampling as well as frequency comb generation. Previous investigations of hybridly mode-locked external-cavity diode lasers (ECDLs), requiring an external modulation, demonstrate the benefit of harmonic mode-locking (ML) on TJ [1]. In order to understand the undisturbed TJ characteristics a PML laser has to be examined. Here, we experimentally investigate the impact of the harmonic mode-locking order (HMLO) and optical feedback (OFB) on the TJ of a PML ECDL and compare these results with the free-running case. We find a high reduction of the long-term timing jitter (TJ_LT) via transitions of the HMLO and by applying long-delay OFB. The findings are confirmed by numerical simulations.

© 2015 IEEE