Color-Converting Violet Laser Diode with an Ultrafast BEHP-PPV + MEH-PPV Polymer Blend for High-Speed White Lighting Data Link

An eye-safe white-lighting source configured with violet laser diode (VLD) and an ultrafast color convertor using the BEHP-PPV + MEH-PPV polymer blend is demonstrated for optical wireless communication system. The BEHP-PPV + MEH-PPV polymer is a mixture of green emitter (BEHP-PPV) and red emitter (MEH-PPV) with a compositional ratio of 5:15 for obtaining warm white light after VLD illumination. For point-to-point 64-quadrature amplitude modulation orthogonal frequency division multiplexing transmission without adding the BEHP-PPV + MEH-PPV blend, the raw data rate can reach as high as 25.2 Gbit/s. After adhering the BEHP-PPV + MEH-PPV polymer blend in front of the VLD for color conversion, it demonstrates a qualified warm white light source with a correlated color temperature of 3606 K, a color rendering index of 84.6 and a CIE coordinate at (0.3768, 0.3226). As a large amount of the VLD power is color converted to broadband luminescence from green- to red-colored light, the transmission performance of this mixed white light source is somewhat degraded. However, the ultrafast time-resolved photoluminescent decay analysis of the BEHP-PPV + MEH-PPV polymer blend reveals a lifetime that enables the maximal transmission data rate to still be reachable to 12.8 Gbit/s with a receiving bit-error ratio of 3.37 × 10–3 below the forward error correction criterion.