Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
135 words
A method of modulating an optical beam, which method comprises providing an etalon structure having an absorption edge in the vicinity of the wavelength of the optical beam and comprising material of a smaller band gap sandwiched between layers of material of a larger band gap so that the smaller band gap material forms a quantum size effect confinement region for electrons and holes, directing the optical beam through the quantum size effect confinement region of the etalon structure and directing a polarised control optical beam at the etalon structure with the electric field of the polarised control optical beam perpendicular to a direction of quantum size effect confinement of the etalon structure to modulate the absorption edge of the etalon structure, thereby causing the optical beam to be modulated by the control optical beam.
Claim 2
Independent Claim
135 words
A method of modulating an optical beam, which method comprises providing an etalon structure having an absorption edge in the vicinity of the wavelength of the optical beam and comprising material of a smaller band gap sandwiched between layers of material of a larger band gap so that the smaller band gap material forms a quantum size effect confinement region for electrons and holes, directing the optical beam through the quantum size effect confinement region of the etalon structure and directing a polarised control optical beam at the etalon structure with the electric field of the polarised control optical beam perpendicular to a direction of quantum size effect confinement of the etalon structure to modulate the absorption edge of the etalon structure, thereby causing the optical beam to be modulated by the control optical beam.
Claim 3
Dependent Claim
25 words
A method according to Claim 1, which comprises providing the quantum size effect confinement region of the etalon structure as at least one quantum well.
Claim 4
Dependent Claim
25 words
A method according to Claim 2, which comprises providing the quantum size effect confinement region of the etalon structure as a multiple quantum well structure.
Claim 5
Dependent Claim
30 words
A method according to Claim 1, 2 or 3, which comprises directing the optical beam through the quantum size effect confinement region perpendicularly of the layers of the etalon structure.
Claim 6
Dependent Claim
30 words
A method according to Claim 1, 2 or 3, which comprises directing the optical beam through the quantum size effect confinement region parallel to the layers of the etalon structure.
Claim 7
Independent Claim
22 words
A method according to any one of the preceding claims, which comprises applying a direct current bias potential across the etalon structure.
Claim 8
Dependent Claim
20 words
A method according to claim 6, which comprises applying the bias potential perpendicularly of the layers of the etalon structure.
Claim 9
Dependent Claim
131 words
Apparatus for modulating an optical beam, which apparatus comprises an etalon structure having an absorption edge in the vicinity of the wavelength of the optical beam to be modulated and comprising material of a smaller band gap sandwiched between layers of material of a larger band gap so that the smaller band gap material forms a quantum size effect confinement region for electrons and holes, and means for directing a polarised control optical beam at the etalon structure with the electric field of the polarised control optical beam perpendicular to a direction of quantum size effect confinement of the etalon structure to modulate the absorption edge of the etalon structure to cause an optical beam passing through the quantum size effect confinement region to be modulated by the control optical beam.
Claim 10
Dependent Claim
131 words
Apparatus for modulating an optical beam, which apparatus comprises an etalon structure having an absorption edge in the vicinity of the wavelength of the optical beam to be modulated and comprising material of a smaller band gap sandwiched between layers of material of a larger band gap so that the smaller band gap material forms a quantum size effect confinement region for electrons and holes, and means for directing a polarised control optical beam at the etalon structure with the electric field of the polarised control optical beam perpendicular to a direction of quantum size effect confinement of the etalon structure to modulate the absorption edge of the etalon structure to cause an optical beam passing through the quantum size effect confinement region to be modulated by the control optical beam.
Claim 11
Dependent Claim
22 words
Apparatus according to Claim 8, wherein the quantum size effect confinement region of the etalon structure comprises at least one quantum well.
Claim 12
Dependent Claim
22 words
Apparatus according to Claim 9, wherein the quantum size effect confinement region of the etalon structure comprises a multiple quantum well structure.
Claim 13
Dependent Claim
24 words
Apparatus according to any one of Claims 8 to 10, which comprises means for applying a direct current bias potential across the etalon structure.
Claim 14
Dependent Claim
24 words
Apparatus according to Claim 11, wherein the means for applying the bias potential comprises electrical contacts provided on opposed surfaces of the etalon structure.