High performance pump laser modules for erbium-doped fiber amplifiers

A 14-pin butterfly pump laser module for erbium-doped fiber amplifiers is described. A high coupling microlens has been realized by etching. A coupling efficiency of 74% has been measured for 1.48-/spl mu/m pump lasers with a variety of far-field angles. The etched microlens is fabricated by batch process and is highly manufacturable. This microlens also provides less reflection and thus interferes less with the operation of lasers. A /spl Delta/T of 60/spl deg/C was measured for an anticipated end-of-life laser chip power dissipation of 1.2 W. The observed performance degradation after a variety of thermal and mechanical shocks is found to be negligible. A maximum change of 5% in coupling efficiency was measured after 2000 hr of 85/spl deg/C bake. The TEC (thermoelectric cooler) resistance measurement showed negligible change, Less than 0.2 dB of temperature tracking error was observed from the routine fabrication data.<>