Uncooled optical semiconductor device
AssigneeMitsubishi Electric Corporation
InventorNorio Okada
Life of this patent
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Abstract
An uncooled optical semiconductor device includes: a semiconductor laser outputting laser light; an electric field absorption optical modulator absorbing light depending on a voltage applied to the electric field absorption optical modulator; a monitor photodiode monitoring backlight of the semiconductor laser; an auto power control circuit feeding back current of the monitor photodiode to a bias current supplied to the semiconductor laser; and a bias circuit feeding back an average value of a light absorption current to control a bias voltage applied to the electric field absorption optical modulator. The light absorption current is generated when the electric field absorption optical modulator absorbs the laser light.
Claims4
An uncooled optical semiconductor device comprising:
- a semiconductor laser outputting laser light in response to a current supplied to the semiconductor laser;
- an electric field absorption optical modulator on which the laser light is incident, wherein the electric field absorption optical modulator
- has an anode and a cathode,
- modulates the laser light by absorption of the laser light in a quantity that varies with a bias voltage applied to the electric field absorption optical modulator, and
- generates a light absorption current in response to the bias voltage applied and the absorption of the laser light;
- a monitor photodiode monitoring and detecting backlight emitted by the semiconductor laser and producing a photocurrent in response to the backlight detected;
- an auto power control circuit responding to the backlight detected by the monitor photodiode by feeding back to the semiconductor laser a current produced in response to the photocurrent, independent of temperature of the semiconductor laser;
- and
- a bias circuit feeding back to the electric field absorption optical modulator an average value of the light absorption current and thereby controlling a bias voltage applied to the electric field absorption optical modulator, irrespective of temperature of the electric field absorption optical modulator.
Dependencies are inferred from the claim text.