Switchable Optical Light Source and Light Switching Unit

A switchable optical light source, comprising:

• a coherent light source;
• and
• a light switching unit configured to receive coherent light from the coherent light source, wherein the light switching unit comprises:
• a first optical resonator into which the coherent light is optically coupled;
• and
• a second optical resonator that is optically coupled to the first optical resonator,
• wherein the first optical resonator and second optical resonator are both Kerr active and Brillouin active,
• wherein by changing a coupling factor corresponding to the optical coupling between the first optical resonator and second optical resonator, and by changing at least one of (A) an optical path length of at least one of the first optical resonator and second optical resonator and (B) a frequency of the coherent light, the switchable optical light source can be switched between:
• operating in a first operational state in which the switchable optical light source functions as a Kerr frequency comb generator;
• and
• operating in a second operational state in which the switchable optical light source functions as a Brillouin laser.