-Band Coherent Wireless Link Using Injection-Locked Laser Diodes

We demonstrate that the simultaneous injection locking of two monolithically integrated distributed feedback (DFB) laser diodes (LDs) with an optical frequency comb is a feasible technique for photonic-based carrier signal generation in the real-time coherent wireless link. The phase of the carrier signal generated by heterodyning the two injection-locked DFB LDs is sufficiently stable to achieve 10-Gb/s error-free (bit-error rate <; 10^-11) coherent wireless transmission in the W-band (75-110 GHz) without active phase stabilization on the transmitter side and digital signal processing on the receiver side. Compared with a direct detection scheme, we show a 17-dB sensitivity improvement using coherent detection. These results open the path toward the development of compact and cost-effective coherent photonic wireless transmitters based on state-of-the-art InP photonic integrated circuit technology, which have wider bandwidth compared with electronics-based transmitters.