The paper presents the design for an experimental indoor optical wireless (OW) diffuse link using the digital pulse interval modulation (DPIM) scheme. Complete system implementation and procedure for carrying out the measurement are given. The system performance in the presence of artificial ambient light (AAL) sources is given. A high pass filter (HPF) with a cut-on frequency of 50 kHz is found to be sufficient to reject the interference signal from all AAL sources with the exception of the high-frequency (HF) fluorescent lamp (FL). Optical filtering reduces the average optical power penalty by 1 dB and 0.2 dB for the low-frequency (LF) FL, and the daylight. For the lowest error rate, the optimum HPF cut-on frequency in the presence of the HF-FL is found to be 884 kHz. The incandescent bulb introduces the largest average optical power penalty of 2.3 dB.