MC-CDMA enhanced LR-PON using widely wavelength lockable FPLD with low facet reflectance

By using a widely wavelength lockable Fabry-Perot laser diode (FPLD) with low facet reflectance under intensity modulation and direct detection, a multicarrier code division multiple access (MC-CDMA) enhanced long-reach passive optical network (LR-PON) architecture is demonstrated to perform the dense-spectral-utilized transmission with orthogonal frequency division multiplexing (OFDM) format. Enlarging the power injected into the low-facet-reflectance FPLD enables the broadening of operational wavelength margins at a cost of slightly increased bit-error rate (BER). After LR-PON transmission, the signal-to-noise ratio among subcarriers strongly correlates with the frequency chirp of the wavelength-locked FPLD, which affects the allowable wavelength locking range. By substituting MC-CDMA for the typical OFDM format and using the minimum-mean-squared-error-based multicode interference cancellation processing, the BER degradation is minimized, accompanied by a 16% extension on the lockable wavelength margin achieved under 3 dBm injection. Such a widely wavelength lockable FPLD-based MC-CDMA enhances the LR-PON with a power penalty reduction of 1 dB as compared to the typical OFDM LR-PON after 60 km transmission.