Light-emitting apparatus capable of selecting polarization direction, optical communication system, and polarization modulation control method
AssigneeCanon Kabushiki Kaisha
InventorJun Nitta
Life of this patent
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Abstract
A light-emitting apparatus capable of selecting polarization direction of a light outputted therefrom includes a semiconductor laser and an optical amplifying device. The semiconductor laser is capable of selectively changing a direction of polarization plane of the output light to one of two orthogonal directions by controlling an excited state. The optical amplifying device amplifies the output light from the semiconductor laser. The optical amplifying device has amplification factors with respect to polarized light components in two orthogonal directions.
Claims21
A light-emitting apparatus comprising:
- light-emitting means capable of selectively changing a direction of a polarization plane of output light to one of two orthogonal directions by controlling an excited state;
- and
- optical amplifying means for amplifying the output light from said light-emitting means, said optical amplifying means having different amplification factors with respect to polarized light components in the two orthogonal directions;
- and
- control means for detecting a change in a voltage between terminals of said optical amplifying means and controlling operation of said light-emitting means based on detection signal so that said light emitting means selectively changes the direction of the polarization plane of output light to one of the two orthogonal directions.
An optical communication system comprising:
- an optical transmission line;
- an optical transmitter;
- and
- an optical receiver,
- said optical transmitter comprising:
- light-emitting means capable of selectively changing a direction of a polarization plane of output light to one of two orthogonal directions by controlling an excited state;
- optical amplifying means for amplifying the output light from said light-emitting means, said optical amplifying means having different amplification factors with respect to polarized light components in the two orthogonal directions;
- and
- control means for detecting a change in a voltage between terminals of said optical amplifying means and controlling operation of said light-emitting means based on a detection signal so that said light emitting means selectively changes the direction of the polarization plane of output light to one of the two orthogonal directions.
A polarization modulation control method for an optical transmitter having light-emitting means which performs modulation by selectively changing a direction of a polarization plane of output light to one of two orthogonal directions by controlling an excited state, comprising the steps of:
- inputting the output light from the light-emitting means to optical amplifying means having different amplification factors with respect to polarized light components in the two orthogonal directions;
- detecting a change in a voltage between terminals of the optical amplifying means;
- and
- controlling light-emitting operation of the light-emitting means based on a detection signal so that the light emitting means selectively changes the direction of the polarization plane of output light to one of the two orthogonal directions.
Dependencies are inferred from the claim text.