A 100 Gb/s Intensity Modulated Direct Detection dispersion tolerant downstream PON with 38 dB power budget based on optical duobinary using low-complex equalization is experimentally demonstrated. Optical duobinary transmission using avalanche photodiodes in combination with Electrical Duobinary Detection is shown for the first time. This combination is very tolerant to bandwidth limitations at both the transmitter and the receiver. Results are further improved upon by using a wider bandwidth Semiconductor Optical Amplifier -filter- P-type Intrinsic N-type receiver. Optical duobinary transmission also permits transmission at higher optical powers without incurring a meaningful penalty. The results show the promise of using the Optical Duobinary scheme for future very high speed cost-effective PON systems beyond 50 Gb/s.