Experimental Demonstration of Single Sideband Modulation Utilizing Monolithic Integrated Injection Locked DFB Laser

Single sideband (SSB) modulation based on a monolithic integrated optically injection-locked (MOIL) DFB laser is demonstrated experimentally. To our knowledge, this is the first time to realize SSB modulation utilizing a MOIL DFB laser. Tunable SSB signals with large lower-to-upper sideband power ratios are achieved by changing the bias currents of the MOIL DFB laser. The largest lower-to-upper sideband power ratio is measured to be 24.4 dB, which is very useful for improving the transmission performance of a radio-over-fiber link. Due to the generated SSB modulation, the fiber transmission response is flattened significantly and a signal of 25 GHz is transmitted through 85-km fiber without being affected by the fiber chromatic dispersion. 20 MSymbol/s 32-QAM signals with subcarriers of 21 GHz, 23 GHz, and 25 GHz are also transmitted by the proposed SSB modulation link, and both the error vector magnitude (EVM) and the bit error rate (BER) of the link are improved distinctly. The proposed method can effectively suppress the fiber chromatic dispersion.