Stabilisation and control of widely tunable MG-Y lasers with integrated photodetectors

Abstract

The control and stabilisation of a widely tunable modulated grating Y-branch (MG-Y) laser are discussed. A characterisation algorithm will be introduced, which produces for each standardised frequency a good operating point with a very small deviation from the wanted output frequency (±2 GHz) and power (±0.2 dB). In addition, a new stabilisation feedback scheme will be presented, which makes use of an external etalon for frequency stabilisation (a wavelength locker) and integrated photodetectors for mode stabilisation. This scheme guarantees that the laser continues operating at the wanted frequency even when the tuning sections degrade or when environmental conditions change. Thanks to those stabilisation algorithms, the lifetime of the device is greatly extended, in case of degrading tuning sections.