Method of fabricating and operating an optical modulator
AssigneeEmcore Corporation
InventorsHenry A. Blauvelt, Xiaoguang He, Kerry Vahala
Life of this patent
Estimating the term…
Abstract
A method of making an optical modulator by determining the material composition of the quantum well region in the waveguide portion of the modulator so that the modulator is transparent at a gain peak wavelength that is greater than the predetermined wavelength by a predetermined amount, and fabricating the modulator with the determined material composition.
Claims20
A method of operating an optical modulator including a semiconductor device having an optical input for receiving a continuous wave coherent light beam having a predetermined power, a waveguide for transferring the light beam, an electrode connected to a radio frequency signal input and a bias potential for creating an electric field in the waveguide and optically modulating the light beam as the beam traverses the waveguide, and an optical output connected to the waveguide for transferring the modulated optical signal, comprising;
- applying a continuous wave (cw) coherent light beam to the optical input;
- and
- applying a bias voltage to the electrode so that the coherent light beam is optically modulated by the signal modulating the absorption characteristic in the semiconductor device so that the waveguide operates in the absorption region at wavelengths less than the gain peak wavelength.
A method of fabricating an optical modulator including a semiconductor device having an optical input for receiving a continuous wave coherent light beam having a predetermined power, a waveguide layer for transferring the light beam, an electrode connected to a radio frequency signal input and a bias potential for creating an electric field in the waveguide and optically modulating the light beam as the beam traverses the waveguide, and an optical output connected to the waveguide for transferring the modulated optical signal, comprising;
- determining the wavelength of the continuous wave coherent light beam to be applied to the modulator;
- determining the gain of an optical signal as a function of wavelength for various predetermined compositions of the waveguide layer;
- fabricating the waveguide layer with a specific composition so that the gain peak of an optical signal as a function of wavelength is greater than the predetermined wavelength of the continuous wave coherent light beam to be applied to the modulator.
A method of fabricating a laser transmitter for optical communications including a semiconductor device including (a) a first semiconductor region for producing a coherent light output in response to current injection;
- and (b) a second semiconductor region disposed adjacent to the first semiconductor region and separated therefrom by a channel, the second semiconductor region having an optical input optically coupled thereto for receiving the coherent light output from the first semiconductor region, and an optical output connected to the second semiconductor region for transferring the modulated optical signal, comprising:
- forming a laser resonator in the first semiconductor region so as to operate at an optical output wavelength;
- forming a semiconductor waveguide structure in the second semiconductor region for transferring the coherent light output from the first semiconductor region light beam;
- forming an optical modulator in the semiconductor waveguide structure, the optical modulator including an active layer including a quantum well region, and an electrode connected to a radio frequency signal input and a bias potential for creating an electric field in the waveguide structure so that the coherent light output is optically modulated as the light beam traverses the waveguide;
- determining the material composition of the quantum well region so that the modulator is transparent at a gain peak wavelength that is greater than the output wavelength of the laser resonator by a predetermined amount;
- and
- fabricating the modulator with said determined material composition.
An electro-optical arrangement comprising:
- a semiconductor device including:
- (a) a first semiconductor region including a laser resonator operable to produce a coherent light output in response to current injection;
- and
- (b) a second semiconductor region disposed adjacent to the first semiconductor region and separated therefrom by a channel, the second semiconductor region having the same composition as the first semiconductor region, and including an optical input optically coupled to the first semiconductor region for receiving the coherent light output from the first semiconductor region, the second semiconductor device being electrically biased at a lower second bias potential than the first semiconductor device and electrically coupled to an radio frequency information-containing signal source, so that current is generated in the second semiconductor device and extracted therefrom, while the coherent light beam is optically modulated by the signal.
Dependencies are inferred from the claim text.