High Power 980 nm Laser Diodes by MBE

In the last few years, high power laser diodes with remarkable improvements concerning output power, efficiency, and reliability have been investigate in the wavelength range between 780 nm and 1064 nm. A lot of the work has been focused on 980 nm, the pump wavelength of Erbium Doped Fiber Amplifiers (EDFAs). Pumping of EDFAs requires highest performance diode lasers due to extreme demands in reliability and beam quality. Up to now, the only type of diode laser used in this application is a single-stripe or ridge-laser which emits in a diffraction-limited optical mode and can therefore be coupled into a single-mode fiber with high efficiency- The small stripe-width limits the reliable output power of these devices to about 300 mW resulting in a fiber coupled output power of less than 250 mW. In the following we report on high-power 980 nm diode lasers comprising ridge and tapered sections for near diffraction emited output power in the watt regime. The devices are based on MBE grown layer structures in the AlInGaAs material system. They allow for more than 500 mW of optical power coupled into a single mode fiber. First reliability tests show extrapolated lifetimes of more than 7.500 h at an output power of 1.8 W.