Hard magnetic garnet material, faraday rotator, optical device, optical communication system, method of manufacturing faraday rotator and method of manufacturing bismuth-substituted rare earth iron garnet single crystal

An optical device comprising:

• a first optical element into which forward light enters;
• a second optical element placed opposite to said first optical element in a predetermined distance from which said forward light is emitted;
• and
• a Faraday rotator placed between said first optical element and said second optical element, which rotates the polarization plane of light that has passed through said first optical element and emits said light toward said second optical element and blocks passage of backward light that has passed through said second optical element,
• wherein said Faraday rotator is constructed of a bismuth-substituted rare earth iron garnet single crystal having a chemical composition of (Bi3-a-b-cGdaTbbYbc) Fe(5-w)MwO12 (where, M is at least one element selected from the group consisting of Ga, Al, Ge, Sc, In, Si and Ti, 0.5≦a+b+c≦2.5, 0.2≦w≦2.5), and
• said bismuth-substituted rare earth iron garnet single crystal exhibits rectangular magnetic hysteresis.

An optical communication system comprising:

• an optical transmitter that issues an optical signal converted from an electric signal;
• an optical transmission line that transmits said optical signal issued form said optical transmitter;
• and
• an optical receiver that receives said optical signal sent through said optical transmission line and converts said received optical signal to an electric signal,
• wherein said optical transmitter comprising:
• an electro-optic converter that converts said electric signal to said optical signal;
• and
• an optical device placed between said electro-optic converter and said optical transmission line,
• wherein a Faraday rotator composing said optical device is constructed of a bismuth-substituted rare earth iron garnet single crystal having a chemical composition of (Bi3-a-b-cGdaTbbYbc)Fe(5-w)MwO12 (where, M is at least one element selected from the group consisting of Ga, Al, Ge, Sc, In, Si and Ti, 0.5≦a+b+c≦2.5, 0.2≦w≦2.5) and said bismuth-substituted rare earth iron garnet single crystal exhibits rectangular magnetic hysteresis.

An optical device comprising:

• a first optical element into which forward light enters;
• a second optical element placed opposite to said first optical element in a predetermined distance from which forward light is emitted;
• and
• a Faraday rotator placed between said first optical element and said second optical element, which rotates the polarization plane of light that has passed through said first optical element and emits said light toward said second optical element and blocks passage of backward light that has passed through said second optical element,
• wherein said Faraday rotator is constructed of a bismuth-substituted rare earth iron garnet single crystal, exhibits rectangular magnetic hysteresis by being heated or cooled with an external magnetic field applied thereto in a direction in which a magnetic field is formed approximately parallel to said forward light and maintains coercive force of 600 Oe or more at room temperature.

An optical device comprising:

• a first optical element into which forward light enters;
• a second optical element placed opposite to said first optical element in a predetermined distance from which said forward light is emitted;
• and
• a Faraday rotator placed between said first optical element and said second optical element, which rotates the polarization plane of light that has passed through said first optical element and emits said light toward said second optical element and blocks passage of backward light that has passed through said second optical element,
• wherein said Faraday rotator is constructed of a bismuth-substituted rare earth iron garnet single crystal, and
• said single crystal includes front and back surfaces placed opposite to each other in a predetermined distance and sides formed around said front and back surfaces and at least one side of said sides has an isotropic pattern.