Optical intensity modulation apparatus and laser systems

An optical intensity modulation apparatus comprising:

• an optical modulator configured to modulate a continuous-wave, cw, optical carrier signal at a carrier wavelength to generate at least one sideband on the optical carrier signal;
• a radio frequency, RF, signal generator configured to provide an RF drive signal to the optical modulator;
• a first optical waveguide grating having a central reflection wavelength substantially corresponding to one of said sideband(s);
• and
• an optical circulator configured to direct the optical carrier signal and the at least one sideband to the first optical waveguide grating and to direct a reflected optical signal from the first optical waveguide grating towards an output to form an output optical signal, wherein a reflection of the optical carrier signal in first optical waveguide grating towards the output is less than 10% of the optical carrier signal directed to the first optical waveguide grating,
• wherein the RF signal generator is configured to switch the RF drive signal on and off so as to form an intensity modulated output optical signal.