Ultra Low Noise (ULN) diode laser modules are designed for applications that require extremely low noise or mode-hop-free operation. Sophisticated drive electronics are used to ensure low noise output. Typical RMS noise is less then 0.06% for detector bandwidth from 10 Hz to 10 MHz, with no warm-up time required. ULN is also speckle-free for vision applications. Buy ULN to improve your signal-to-noise, dynamic range and resolution.
ULN Series of laser diode modules feature an alternative solution to the mode-hop problem. Rather than regulate temperature, a special modulation is used to force the laser into a multi-longitudinal mode.
While a normal laser will operate in a single-mode longitudinal or oscillate between two strong modes, the modulation creates several modes of lower intensity. As the laser temperature increases, these modes move like a caterpillar across the wavelength spectrum. The movement does not allow abrupt changes, so the system operates as if there were no mode-hops.
The result is low RMS noise (~0.06%), which is stable over changes in temperature and the life of the diode laser module.
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