Widely wavelength-tunable DFB laser array integrated with funnel combiner

A wavelength-tunable distributed feedback (DFB) laser array integrated with a funnel combiner is described. Two types of optical combiner, namely a multimode interferometer (MMI) combiner and a funnel combiner, are compared theoretically and experimentally. It is shown that the funnel combiner is superior in terms of wavelength dependence and fabrication tolerance. The laser module covers the full C-band wavelength range (similar to 38 nin), and a high fiber output power of 40 mW (16 dBm) is obtained with stable single-mode operation.