Enhancing Coherent Combining Efficiency via Choosing Appropriate Lasing Wavelength in a Michelson Compound Cavity Based on Two 3dB Fibre Loop Mirrors and One Fibre Bragg Grating

Enhancing coherent combining efficiency via choosing appropriate lasing wavelength in a Michelson compound cavity based on two 3dB fibre loop mirrors and one fibre Bragg grating (FBG) has been experimentally demonstrated. The FBG with 4.5% reflectivity is replaced at the cleaved facet with 4% Fresnel reflection. A high coherent combining efficiency of 93.5% is obtained when the FBG with central wavelength at 1559.845nm is introduced into the cavity, while it is only 90.1% combining efficiency with the FBG at central wavelength 1557.830nm. In comparison with other reports, the proposed compound-cavity laser has the advantage of needless tuning FBG to obtain the coherent condition, and it is facile to ascertain the seemly
wavelength lasing for a Michelson compound cavity.