GCSR laser frequency drift compensation using optimized current waveform on one single electrode

In this paper we present a new method to compensate the whole frequency deviation due to thermal drift during wavelength switching for a semiconductor laser based on launching a distorted current pulse just on one of the tuning electrodes of the laser. We experimentally confirm its efficiency compared with the time constant technique.

1. Introduction

Grating assisted Codirectional Coupler with rear Sampled grating Reflector (GCSR) laser is a multi-electrode fast tunable semiconductor laser source with wide and fine tunability. For this laser to be used in Optical Packet Switching (OPS) environments the control of the wavelength switching characteristics is required. The low driving currents it needs to be tuned make feasible to control successfully its frequency derive, governed by thermal and carrier effects due to the current injection at switching, switching from short ns to . For example, state-of-art lasers suffer from fast mode hopping and undesirable counteracting slower thermal drifts of optical frequency toward a steady state value. Wavelength-agile OPS systems require short tuning and setting time, low interference over neighbouring channels and low wavelength drift.