Homodyne interferometric receiver and calibration method having improved accuracy and functionality

A method capable of measuring the phase difference between two orthogonally polarized components of a polarized test beam and the intensities of these components, said method comprising the steps of:

• dividing said polarized test beam into first and second spatially separated beams, said test beam having p and s components such that p represents a polarization direction and s represents an orthogonal polarization direction, said p and s components being unequally divided into said first and second spatially separated beams;
• retarding the phase of one of the unequally divided polarization components with respect to the other unequally divided polarization component in said spatially separated beams;
• producing a first pair of spatially separated output beams with mutually orthogonal linear polarizations from said phase retarded first spatially separated beam, said first pair of output beams comprising substantially equal amounts of the s and p polarization components of said phase retarded first spatially separated beam;
• converting said first pair of output beams into a first set of electrical signals proportional to the conversion output beam intensity and providing said first set of electrical signals to a data processor for analysis thereof;
• producing a second pair of spatially separated output beams with mutually orthogonal linear polarizations from said second spatially separated beam, and second pair of output beams comprising substantially equal amounts of the s and p polarization components of said second spatially separated beam;
• converting said second pair of output beams into a second set of electrical signals proportional to the corresponding output beam intensity and providing said second set of electrical signals to said data processor for analysis thereof along with said first set of electrical signals;
• and
• determining at least the relative intensities of the unequally divided s and p polarization components of said test beam from said analysis of said electrical signal for measuring the relative strengths of the s and p polarization states of said test beam.

A homodyne receiver apparatus capable of measuring the phase difference between two orthogonally polarized components of a polarized test beam and the intensities of these components, said apparatus comprising:

• means for receiving said polarized test beam and dividing it into first and second spatially separated beams, said test beam having s and p components such that p represents a polarization direction and s represents an orthogonal polarization direction, said means for receiving and dividing said test beam further comprising means for unequally dividing said s and p components into said first and second spatially separated beams:
• phase retarding means optically aligned with one of said spatially separated beams for retarding the phase of one of the unequally divided polarization components with respect to the other unequally divided polarization component of said spatially separated beams passing through said phase retarding means for providing a phase retarded spatially separated beam;
• polarizing beamsplitting means optically aligned with said phase retarded first spatially separated beam and with said second spatially separated beam, respectively, for producing first and second pairs of spatially separated output beams, respectively, each having mutually orthogonal linear polarizations with each of said first pair of output beams having substantially equal amounts of the s and p polarization components of said phase retarded first spatially separated beam and with each of said second pair of output beams having substantially equal amounts of the s and p polarization components of said second spatially separated beam;
• photodetector means optically aligned with each of said output beams for producing a set of electrical signals proportional to the respective output beam intensities of said output beams;
• and
• means for determining at least the phase difference between said unequally divided s and p polarization components of said test beam from said electrical signals;
• whereby said phase retarding means and said polarizing beam splitting means may comprise imperfect components.

A homodyne receiver apparatus capable of measuring the phase difference between two orthogonally polarized components of a polarized test beam and the intensities of these components, said apparatus comprising:

• means for receiving said polarized test beam and dividing it into first and second spatially separated beams, said test beam having s and p components such that p represents a polarization direction and s represents an orthogonal polarization direction, said means for receiving and dividing said test beam further comprising means for unequally dividing said s and p components into said first and second spatially separated beams;
• phase retarding means optically aligned with one of said spatially separated beams for retarding the phase of one of the unequally divided polarization components with respect to the other unequally divided polarization component of said spatially separated beams passing through said phase retarding means for providing a phase retarded spatially separated beam;
• polarizing beamsplitting means optically aligned with said phase retarded first spatially separated beam and with said second spatially separated beam, respectively, for producing first and second pairs of spatially separated output beams, respectively, each having mutually orthogonal linear polarizations with each of said first pair of output beams having substantially equal amounts of the s and p polarization components of said phase retarded first spatially separated beam and with each of said second pair of output beams having substantially equal amounts of the s and p polarization components of said second spatially separated beam;
• photodetector means optically aligned with each of said output beams for producing a set of electrical signals proportional to the respective output beam intensities of said output beams;
• and
• means for determining at least the relative intensities of the unequally divided s and p polarization components of said test beam from said electrical signals for measuring the relative strengths of the s and p polarizations of said test beam.