Light source

A light source comprising a nonlinear optical element for supercontinuum generation, where the light source is capable of switching between operating in a high power mode and a low power mode while mitigating accelerated degradation of the nonlinear optical element in the high power mode,

• the light source comprising:
• a pulse generator for providing an initial sequence of light pulses, the initial sequence of light pulses comprising an initial number of light pulses within a predetermined time period,
• first and second optical arms, for propagating, respectively, first and second sequences of light pulses, each derived from the initial sequence of light pulses,
• wherein the first optical arm comprises a first manipulator configured to generate the first sequence of light pulses from the initial sequence of light pulses, the first sequence of light pulses having a first number of light pulses within the predetermined time period, wherein the first number is higher than the initial number, wherein the first manipulator comprises a plurality of optical fibers,
• wherein the second sequence of light pulses has a second number of light pulses within the predetermined time period, wherein the second number is equal to or lower than the initial number,
• an optical switch arranged to switch either the first sequence of light pulses or the second sequence of light pulses for reception by the nonlinear optical element,
• at least one amplifier arranged upstream of the nonlinear optical element,
• a controller in communication with the optical switch and the amplifier;
• where the controller is configured for controlling the amplification of pulses depending on the setting of the optical switch, such that pulses of the first sequence are amplified more than pulses of the second sequence whereby the high order mode is provided while mitigating accelerated degradation of the nonlinear optical element,
• wherein the light source is a broadband light source.