A Novel Colorless FPLD Packaged With TO-Can for 30-Gbit/s Preamplified 64-QAM-OFDM Transmission

A colorless FPLD directly modulated by the preamplified 64-QAM-OFDM at 30 Gbit/s is demonstrated with suppressed intensity noise and modulation distortion due to the enhanced signal-to-noise ratio (SNR) and reduced frequency chirp. To encode the colorless FPLD with 90% modulation depth when up shifting the dc bias to 2.5 times threshold of the colorless FPLD under injection-locking at 3 dBm, the preamplification of the electrical 64-QAM-OFDM data achieves the least SNR degradation and maintains data extinction. With the 64-QAM-OFDM subcarrier amplitude preleveled and preamplified encoding procedure, the colorless FPLD effectively promotes high on/off data extinction by suppressing the throughput power declination to <;5 dB and reducing the power-to-frequency slope to -0.7 dB/GHz within 5-GHz modulation bandwidth. The received bit-error-rate (BER) contour map of the preamplified 64-QAM-OFDM data carried by the colorless FPLD achieves its minimum of <;2.0 × 10^-3 and reveals large tolerances to the injection power and the biasing level. After preleveling the amplitude slope of the OFDM subcarriers, the error vector magnitude reduces to 8.6% and the SNR enhances to 21.2dB even after 25-km SMF transmission. The colorless FPLD encoded by preamplified and preleveled 64-QAM-OFDM data apparently optimizes both back-to-back and 25-km transmissions with corresponding BERs minimized to 1.1 × 10^-3 and 3.5 × 10^-3, respectively.