Direct phase modulation of DFB is demonstrated with DPSK, DQPSK and Duobinary modulation formats and detected with an intradyne receiver based on a 120-degree hybrid. The system is tested in a 50 km fibre link with 6.25 GHz channel spacing among users in a UDWDM-PON. By using higher modulation formats, the spectral efficiency can be increased in a single carrier system without spectral shaping while achieving an Rx sensitivity of -40 dBm at BER = 10-3for 5 Gb/s in a 2 GHz bandwidth limited DFB.