Contents I. Introduction
The dense wavelength division multiplexed passive optical network (DWDM-PON) has emerged as a promising broadband access network for large capacity and high security communication with easy upgradability. In DWDM-PON, the light source with a broadband gain spectrum is required to offer each optical network unit (ONU) its own channel wavelength. The injection-locked weak-resonant-cavity FPLD (WRC-FPLD) transmitter has been considered to be one candidate owing to its comparable gain spectral linewidth but a better coherence with the reflective semiconductor optical amplifier (ROSA) [1], [2]. However, reducing the anti-reflective (AR) coating reflectance also impairs the transmission performance. Therefore, the fine tuning of AR coating reflectance for a WRC-FPLD with acceptable bandwidth and suppressed noise background is important. In this work, two coherently injection-locked and directly modulated WRC-FPLDs with AR coating reflectance of 0.5% and 1.2% are demonstrated to compare the characteristic parameters such as the relative intensity noise (RIN), extinction ration (ER), signal-to-noise ratio (SNR), and bit-error-rate (BER) when transmitting in a 1.25-Gbit/s DWDM-PON system.
