Two thin-clad laser diodes are disposed to form a stack-type diode laser
device. The diodes emit two beams that are substantially parallel and in
proximity such that they share many fiberoptic systems designed for a
single beam. The diodes are coupled by leaky waves through top surfaces.
The leaky waves are generated by a thin metal contact layer or
diffractive gratings. The stack-type device is employed for single-mode
power enhancement and tunable lasers.