Micromachined tunable vertical cavity lasers as wavelength selective tunable photodetectors

Micromachined tunable VCSELs are particularly useful for wavelength division multiplexing applications because of their large continuous wavelength tuning range without mode-hopping. We have achieved 26 nm single mode continuous wavelength tuning with threshold current density as low as 550 A/cm². By reverse biasing the laser, we can obtain a tunable resonant cavity photodetector with simulated linewidth less than 2 nm. Narrow linewidth tunable photodetectors are particularly useful in extending the wavelength separation between WDM channels beyond those offered by other techniques