Flexible high-order QAM transmitters for elastic optical networks

In order to adapt to the dynamics in the future optical networks, we propose and experimentally two flexible high-order quadrature amplitude modulation (QAM) transmitter schemes: i) a flexible transmitter using a tandem in-phase/quadrature (IQ) modulators for generating 16-/32-/64-QAM signals; and ii) a scheme based on monolithically-integrated quad Mach-Zehnder in-phase/quadrature (QMZ-IQ) with binary driving electronics for synthesizing minimum phase-shift keying (MSK), quadrature phase-shift keying (QPSK), 8-ary phase shift keying (8PSK), and 16QAM. The flexibility and re-configurability of the proposed schemes are experimentally verified.