Broadband optical phase detection and phase noise removal with an optical resonator

A phase noise detection apparatus comprising:

• at least one laser beam, an optical resonator coupled to the at least one laser beam at a coupling point, and a photodetector arranged to receive light from the laser beam, wherein
• the at least one laser beam and the resonator coupled thereto convert phase noise of light transported by the at least one laser beam prior to the coupling point into intensity noise of light transported by the at least one laser beam after the coupling point, wherein the intensity noise after the coupling point is generated as a function of the phase noise prior to the coupling point, and
• said photodetector is adapted to convert the intensity noise into an electrical signal;
• and
• at least one electrical signal path and at least one optical phase modulator, wherein
• the at least one electrical signal path is adapted to apply the electrical signal to the at least one optical phase modulator, and
• the at least one electrical signal path includes first and second electrical signal paths adapted for the electrical signal to be sent thereto, to the first electrical signal path with a signal substantially proportional to the intensity noise, and to the second electrical signal path where a signal substantially proportional to the intensity noise is integrated, wherein the first and the second electrical signal paths are connected to the at least one phase modulator compensating phase noise in an optical domain, and said at least one phase modulator is (i) one out of several optical phase modulators or (ii) a unique optical phase modulator wherein both electrical signal paths are combined in an electrical domain prior to being applied to said unique optical modulator.