A device controller (16) for directing a drive current (12A) to a device (12) includes a current driven power source (40) that is electrically connected to the device (12); and a current adjuster (22) electrically connected to the power source (40) in parallel to the device (12). The current adjuster (22) selectively adjusts the drive current (12A) directed to the device (12). For a laser (12), the current adjuster (22) can adjust the drive current (12A) to modulate a center wavelength of an illumination beam (20) generated by the laser (12).