  In this study, incoherent light with a spectral linewidth of 7 nm and 140 mW
of power was generated from a laser diode into which incoherent light emitted
from a superluminescent diode was injected with 2.7 mW of power. The spectral
linewidth of the light from the laser diode was broadened to 12 nm when the
diode's output power was reduced to 15 mW. In the process of transformation
from single-mode laser light to incoherent light with a broad spectrum by
increasing injection-light power, multimode laser oscillation and a noisy
spectrum were found in the light from the laser diode. This optical system can
be used not only for amplification of incoherent light but also as a
coherence-convertible light source.
