We demonstrate an indoor 5 m free-space optical wireless coherent communication in mid L-band(1606.7 nm)by employing a tunable self-seeded InAs/InGaAlAs/InP quantum-dash(Qdash) laser as a subcarrier generator for 128 Gb/s dual-polarization quadrature phase shift keying(DP-QPSK) modulation signal. The bare Qdash laser diode displays ~6 nm self-locked Fabry–Perot mode tunability with ~30 dB side mode suppression ratio(SMSR) and ~10 dBm mode power across the tuning range, thus encompassing ~10 modes with an achievable capacity of 1.28 Tb/s(10 × 128 Gb∕s) and potentially qualifying the source requirements for future access networks. We demonstrate an indoor 5 m free-space optical wireless coherent communication in mid L-band (1606.7 nm) by employing a tunable self-seeded InAs / InGaAlAs / InP quantum-dash (Qdash) laser as a subcarrier generator for 128 Gb / s Dual-polarization quadrature phase shift keying (DP-QPSK) modulation signal. The bare Qdash laser diode displays ~ 6 nm self-locked Fabry-Perot mode tunability with ~ 30 dB side mode suppression ratio (SMSR) the tuning range, thus encompassing ~ 10 modes with an achievable capacity of 1.28 Tb / s (10 × 128 Gb / s) and potentially qualifying the source requirements for future access networks.