title: Optical 16-QAM-52-OFDM transmission at 4 Gbit/s by directly modulating a coherently injection-locked colorless laser diode.
abstract: Coherently injection-locked and directly modulated weak-resonant-cavity laser diode (WRC-FPLD) for back-to-back optical 16-quadrature-amplitude-modulation (QAM) and 52-subcarrier orthogonal frequency division multiplexing (OFDM) transmission with maximum bit rate up to 4 Gbit/s at carrier frequency of 2.5 GHz is demonstrated. The WRC-FPLD transmitter source is a specific design with very weak-resonant longitudinal modes to preserve its broadband gain spectral characteristics for serving as a colorless WDM-PON transmitter. Under coherent injection-locking, the relative-intensity noise (RIN) of the injection-locked WRC-FPLD can be suppressed to ?105 dBc/Hz and the error vector magnitude of the received optical OFDM data is greatly reduced with the amplitude error suppressed down 5.5%. Such a coherently injection-locked single-mode WRC-FPLD can perform both the back-to-back and the 25-km-SMF 16-QAM-52-OFDM transmissions with a symbol rate of 20-MSa/s in each OFDM subcarrier. After coherent injection locking, the BER of the back-to-back transmitted 16-QAM-52-OFDM data is reduced to 2.5 × 10(-5) at receiving power of ?10 dBm. After propagating along a 25-km-long SMF, a receiving power sensitivity of ?7.5 dBm is required to obtain a lowest BER of 2.5 × 10(-5), and a power penalty of 2.7 dB is observed when comparing with the back-to-back transmission.
authors.affiliation: Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Yu-Chieh
authors.initials: YC
authors.lastname: Chi
authors.forename: Yi-Cheng
authors.initials: YC
authors.lastname: Li
authors.forename: Huai-Yung
authors.initials: HY
authors.lastname: Wang
authors.forename: Peng-Chun
authors.initials: PC
authors.lastname: Peng
authors.forename: Hai-Han
authors.initials: HH
authors.lastname: Lu
authors.forename: Gong-Ru
authors.initials: GR
authors.lastname: Lin
mesh_terms: D003116:Color; D004867:Equipment Design; D019544:Equipment Failure Analysis; D054023:Lasers, Semiconductor; D008872:Microwaves; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*