Multi-Wavelength DFB Laser with High Mode Stability and Uniform Spacing for Optical I/O Technology

We propose and experimentally demonstrate a novel multi-wavelength DFB laser with high mode stability and uniform spacing for the optical I/O technology. By employing the linearly chirped sampled grating and multiple equivalent π phase shifts among the cavity, the four-wavelength and six-wavelength lasers with 100 GHz spacing are implemented and experimentally validated. The proposed multi-wavelength DFB laser works with high mode stability, high uniform wavelength spacing, and high uniform output power with varied bias currents and operating temperatures. A semiconductor optical amplifier is monolithically integrated to amplify the output and the output power exceeds 25 mW when the current injected into the SOA is 120 mA. Besides, the relative intensity noise of the filtered wavelengths is below -130 dB/Hz for each wavelength, and clear 25 Gb/s NRZ eye grams are obtained for the filtered each wavelength with the external lithium-niobate Mach-Zehnder modulator, which indicates the capability of the proposed structure to be an alternative approach for the multi-wavelength optical sources in DWDM optical I/O links.