Compact power-equalized multi-wavelength DFB laser with high uniform wavelength spacing for optical I/O technology

In this Letter, we propose and experimentally demonstrate, to the best of our knowledge, a novel compact power-equalized multi-wavelength laser (MWL) source for optical I/O technology.This multi-wavelength distributed feedback (DFB) laser array is used to achieve simultaneous emission of multiple wavelengths with balanced output power and stable single-mode operation.The reconstruction equivalent chirp technique is used to design and fabricate the -phase shifted DFB laser array to achieve precise wavelength spacing.The power equalizers (PEs) are monolithically integrated in front of the laser unit to equalize the output power.The experimental results show that the wavelength spacing of the proposed eight-channel MWL is 100 G 4.38 G, and the maximum deviation of the intensity (MDOI) is 1.00 dB under a 25C working environment.Compared with the traditional MWL structure, the wavelength spacing error is reduced from 0.32 to 0.035 nm, and the MODI is reduced from 3.8 to 1.0 dB.The output power exceeds 25 mW when the current injected into the semiconductor optical amplifier (SOA) is 150 mA.Besides, the relative intensity noise (RIN) of all wavelengths is below -138 dB/Hz, and clear 25 Gb/s non-return-tozero (NRZ) eye diagrams are obtained for the eight wavelengths with the external lithium-niobate Mach-Zehnder modulator.The superior performance of the proposed MWL makes it a promising method for low-bit-error optical I/O links and highdensity chip interconnection systems.