title: Flexible terabit/s Nyquist-WDM super-channels using a gain-switched comb source.
abstract: Terabit/s super-channels are likely to become the standard for next-generation optical networks and optical interconnects. A particularly promising approach exploits optical frequency combs for super-channel generation. We show that injection locking of a gain-switched laser diode can be used to generate frequency combs that are particularly well suited for terabit/s super-channel transmission. This approach stands out due to its extraordinary stability and flexibility in tuning both center wavelength and line spacing. We perform a series of transmission experiments using different comb line spacings and modulation formats. Using 9 comb lines and 16QAM signaling, an aggregate line rate (net data rate) of 1.296 Tbit/s (1.109 Tbit/s) is achieved for transmission over 150 km of standard single mode fiber (SSMF) using a spectral bandwidth of 166.5 GHz, which corresponds to a (net) spectral efficiency of 7.8 bit/s/Hz (6.7 bit/s/Hz). The line rate (net data rate) can be boosted to 2.112 Tbit/s (1.867 Tbit/s) for transmission over 300 km of SSMF by using a bandwidth of 300 GHz and QPSK modulation on the weaker carriers. For the reported net data rates and spectral efficiencies, we assume a variable overhead of either 7% or 20% for forward- error correction depending on the individual sub-channel quality after fiber transmission.
authors.forename: Joerg
authors.initials: J
authors.lastname: Pfeifle
authors.forename: Vidak
authors.initials: V
authors.lastname: Vujicic
authors.forename: Regan T
authors.initials: RT
authors.lastname: Watts
authors.forename: Philipp C
authors.initials: PC
authors.lastname: Schindler
authors.forename: Claudius
authors.initials: C
authors.lastname: Weimann
authors.forename: Rui
authors.initials: R
authors.lastname: Zhou
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Freude
authors.forename: Liam P
authors.initials: LP
authors.lastname: Barry
authors.forename: Christian
authors.initials: C
authors.lastname: Koos