64 and 128 coherent QAM optical transmission over 150 km using frequency-stabilized laser and heterodyne PLL detection

Abstract

We describe 1 Gsymbol/s, 64 and 128 coherent quadrature amplitude modulation (QAM) transmissions over 150 km, in which we employ a frequency-stabilized C(2)H(2) fiber laser, an optical phase-looked loop (OPLL), and a heterodyne detection circuit.