High-speed data and pulse-carver alignment in dual Mach-Zehnder modulator optical transmitters using microwave signal processing

A novel approach is presented for aligning the pulse carver and data modulator in a dual Mach-Zehnder (MZ) modulator optical transmitter. This technique relies solely on the photodiode detected microwave power spectrum of the transmitted optical signal. Experimental results are presented that illustrate the spectral property to be exploited and two proposed techniques for designing a low cost automated carver and modulator alignment system. A mathematical explanation for the spectral phenomenon is presented and shown to agree quite well with measurement and simulation results.