Chirp-managed lasers as cost-efficient transmitters for 10-Gbit/s WDM-PONs

Chirp-managed lasers (CML) are demonstrated as simple low-cost transmitter with high tolerance to chromatic dispersion. This manuscript proposes the use of CML as cost-effective downstream (DS) transmitters for next generation access networks. The laser chirp, which is the main drawback limiting the transmission performance of directly modulated lasers, is now used to generate differential phase-shift keying (DPSK) modulation format by direct modulation. The network architecture using CML as downstream DPSK transmitter is proposed. Bit­ error-rate measurement showed that an optical power budget of 36 dB could be obtained with direct phase-shift­ keying modulation ofCML which proves that the proposed solution is a strong candidate for future WDM-PONs. Budget-extended WDM-PON configuration is also demonstrated using Saturated Collision Amplifier, which is an amplification scheme that uses SOA saturation in order to maximize the output power and minimize the ASE noise and the polarization sensitivity. The extension scheme is demonstrated for four-wavelength 10 Gbit/s unidirectional downstream configuration with 60-dB maximum total optical budget for each wavelength.