Long-wavelength vertical-cavity semiconductor optical amplifiers

Vertical-cavity semiconductor optical amplifiers (VCSOAs) are interesting devices because of their small form factor, potential low manufacturing cost, high coupling efficiency to optical fiber, and polarization independent gain. In this paper, an overview of the properties and possible applications of long-wavelength VCSOAs is given. We present general design rules and analyze how the mirror reflectivity affects the properties of the VCSOA. Experimental results of reflection-mode VCSOAs operating at 1.3-μm wavelength are presented. The devices were fabricated using InP-GaAs wafer bonding and were optically pumped by a 980-nm laser diode. These VCSOAs have demonstrated the highest fiber-to-fiber gain (17 dB), as well as the highest saturation output power (-3.5 dBm) of any long-wavelength VCSOA to date. We have also used these VCSOAs for optical preamplification at 10 Gb/s. Using an 11-dB gain VCSOA, the sensitivity of a regular PIN detector was increased by 7 dB resulting in a receiver sensitivity of -26.2 dBm.