Chen Bai

Single Mode Er-Doped π-Phase-Shifted Distributed Feedback Fibre Grating Laser

A novel method incorporating the shielded method and the post-processing method has been proposed to fabricate the pi-phase-shilted fibre grating. Then an Er-doped pi-phase-shifted distributed feedback fibre grating laser has been fabricated using the grating. The laser threshold is 20 mW. When pumped with 90 mW light at 980 nm, the laser gives an output of 1.1 mW. Its signal-to-noise ratio is better than 60 dB. It is demonstrated that the laser is single mode operation by means of a Fabry-Perot scanning interferometer.

Yb3+-doped non-π-phase-shifted distributed feedback fibre lasers

Distributed feedback (DFB) fibre lasers usually have two longitudinal modes symmetrically located at each side of the Bragg wavelength because they have the same lowest gain threshold. In order to obtain single longitudinal output, π-phase-shifted DFB fibre lasers are often adopted. However, we found that, even with no π-phase-shift, the single frequency output can be acquired from Yb3+-doped fibre DFB lasers. The polarization beat frequency was measured to be 366 MHz.

Theoretical modelling of the effect of photon lifetime on the output dynamics of Er-doped distributed feedback fibre lasers

By employing a simple model of describing three-level lasers, we have theoretically investigated the effect of photon lifetime on the output dynamics of Er-doped distributed feedback fibre lasers. And based on the theoretical analysis we have proposed a promising method to suppress self-pulsing behaviour in the fibre lasers.