Broadly-tunable narrow-linewidth micromachined laser/photodetector and phototransistor

The key limitation to dense wavelength division multiplexing (WDM) systems is the receiving end since laser linewidths are typically less than 1 /spl Aring/. By reverse biasing the p-i-n diode region, we demonstrated dual functionality of wavelength-tunable vertical-cavity surface-emitting lasers (VCSELs) as wavelength-tunable resonant cavity photodetectors (RCPs) with linewidths less than 2.5 nm. Additionally, we have fabricated wavelength-tunable resonant cavity phototransistors (RCPTs) with linewidths as narrow as 1.7 nm. Wavelength-tunable RCPTs are capable of high quantum efficiency, narrow linewidth, and high-speed operation, making them ideal devices for WDM receivers.