Optical head for hologram optical apparatus and method of operating the same

An optical head for a hologram optical apparatus, the optical head comprising:

• a reference light unit which generates a reference light for hologram recording;
• a signal light unit which generates a signal light for hologram recording;
• and
• a light source unit which provides light to the reference light unit and the signal light unit,
• wherein the reference light unit and the signal light unit are vertically stacked, and
• wherein the signal light unit comprises:
• a plurality of optical waveguides stacked vertically;
• a composite hologram optical element and a lighting hologram optical element, each comprising a single layer hologram, disposed on each of the plurality of optical waveguides;
• an optical modulator which modulates light output from the plurality of optical waveguides;
• and
• a lens which condenses light emitted from the optical modulator onto the hologram recording layer.

A method of operating an optical head of a hologram optical apparatus, the method comprising:

• a light source unit generating reference light and signal light;
• a reference light unit directing the reference light from the light source unit to a hologram recording layer;
• a signal light unit directing the signal light from the light source unit to the hologram recording layer;
• wherein the reference light generating unit and the signal light generating unit are vertically stacked;
• wherein the signal light generating unit comprises an optical waveguide, a composite hologram optical element disposed on the optical waveguide, and a lighting hologram optical element disposed on the optical waveguide;
• and
• wherein the method further comprises adjusting at least one of a thickness and a refractive index modulation of the composite hologram optical element.