Tunable dual-wavelength picosecond pulse generation using multiple-optical-path self-seeding approach

A simple system is developed to generate tunable dual-wavelength optical pulses by self-injection seeding of a laser diode. The wavelengths are selected by controlling two light paths incident on a single diffraction grating. The spectral separation has been tuned from 1.8 to 16.1 nm while maintaining an output side-mode-suppression-ratio (SMSR) over 21 dB. This multiple-optical-path self-seeding approach is simple and efficient, thus providing an attractive alternative to generate tunable multiwavelength pulses.