A low-
noise laser diode module comprises a
laser diode for emitting light with a
wavelength in the range from UV to IR, a drive circuit for injecting
electrical current into said
diode, and an
automatic power control circuit for monitoring and adjusting
laser output power using front-
facet photodiode external to the laser
assembly and a
feedback loop. Said drive circuit produces injection current modulated by an RF
signal with variable degrees, depending on the
wavelength to be stabilized, the desired spectral bandwidths of the laser output, and / or other applications. Said RF
signal can be a
sine wave, a distorted
sine wave, a rectified
sine wave, a non-sine wave, a series of narrow pulses, or repetitive shunt. The present invention encompasses a method for producing stable,
broadband, and low-coherent laser. The present invention also encompasses a method for producing stable
narrowband or single
longitudinal mode laser. The present invention further encompasses a compact
light source applicable to DPSS lasers,
fiber lasers, optical parametric oscillators, low-speckle
laser display systems, and seeders, with or without nonlinear
frequency conversion processes.