A PROPOSAL OF BROAD-BANDWIDTH VERTICAL-CAVITY LASER-AMPLIFIER

We propose a generic vertical-cavity amplifier (VCA) using a coupled-c avity design to broaden the bandwidth. Calculations are made for cavit ies with GaAs-AlAs and GaAs-AlxO2 distributed Bragg reflectors (DBR). We found that at reasonable pumping levels the VCA increased the bandw idth by 85% (GaAs-AlAs) to 500% (GaAs-Al2O2) as compared to a simple t wo-mirror structure similar to vertical-cavity surface-emitting lasers . In particular, the GaAs-AlAs VCA shows a bandwidth of 2 mn at 6-dB s ignal gain, while the GaAs-AlxO2 VCA demonstrates a 5-nm bandwidth at 6-dB signal gain with no ripple at required single-pass power gain of similar to 2-2.5%. Furthermore, as large as 30-nm bandwidth in a lossl ess bandpass filter can be obtained.