Chirp reduction using push-pull modulation of three-contact lasers

Low-chirp modulation of three-contact distributed-feedback (DFB) lasers is experimentally demonstrated, using a push-pull modulation scheme. When the laser was modulated with a 2.0-Gb/s pseudorandom bit sequence, the -20-dB linewidth was measured to be 0.055 nm after deconvolving the measurement equipment's response. The results are simulated using a large-signal time-domain model that illustrates the mechanisms responsible for the low chirp. The grating structure is shown to have a significant effect on the performance of the device under push-pull modulation.<
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