Driver circuit and optical-transmission module
AssigneeOpnext Japan, Inc.
InventorsNorio Chujo, Yoshihiko Hayashi, Akio Osaki, Naohiko Baba
Life of this patent
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Abstract
A driver circuit comprises a first differential-amplifier circuit having a pair of first transistors with emitters thereof connected to each other and a first resistor provided between an emitter connection point of the first transistors and a first power supply. Different electric potentials are applied to the bases of the pair of the first transistors to set a ratio of a current flowing through one of the pair of the first transistors to a current flowing through the other first transistor at about 1/100 or smaller. An amplitude of an output current is controlled by the higher of the electric potentials applied to the base of one of the first transistors.
Claims18
A method of transmitting an optical transmission wave comprising:
- a first step of making a signal time-division multiplexed in a MUX circuit;
- a second step of adding a header to the signal in a header adding circuit electrically connected to the MUX circuit, the header including information for error detection;
- a third step of protecting the signal from continuing the same date “0” or “1” in a scrambling circuit electrically connected to the header adding circuit;
- and
- a fourth step of outputting the optical transmission wave comprising the signal in a driver circuit in a optical-transmission module electrically connected to the scrambling circuit,
- wherein the driver circuit comprises a first differential amplifier circuit having a pair of first transistors with emitters thereof connected to each other and a first resistor provided between an emitter connection point of the first transistors and a first power supply;
- wherein a higher base voltage is applied to the base of one of the first transistors than a base voltage applied to the base of the other first transistor, and
- wherein, with a difference in electric potential applied by the base voltages between bases of the pair of the first transistors to set a ratio of a current flowing through one of the pair of the first transistors to a current flowing through the other first transistor at about 1/100 or smaller, an amplitude of an output current of the driver circuit is controlled by the higher electric voltage applied to the base of one of the first transistors than to the base of the other first transistor.
A method of transmitting an optical transmission wave comprising:
- a first step of making a signal time-division multiplexed in a MUX circuit;
- a second step of adding a header to the signal in a header adding circuit electrically connected to the MUX circuit, the header including information for error detection;
- a third step of protecting the signal from continuing the same date “0” or “1” in a scrambling circuit electrically connected to the header adding circuit;
- and
- a fourth step of outputting the optical transmission wave comprising the signal in a driver circuit in an optical-transmission module electrically connected to the scrambling circuit;
- wherein the driver circuit comprises a first differential-amplifier circuit having of a pair of first transistors employing bipolar transistors with emitters thereof connected to each other and a first resistor with resistance in a range of about 2 to 20Ω provided between an emitter connection point of the pair of the first transistors and first power supply;
- and
- wherein an amplitude of an output current of the driver circuit is controlled by electric potential applied to a base of at least one of the first transistors.
A method of transmitting an optical transmission wave comprising:
- a first step of making a signal time-division multiplexed in a MUX circuit;
- a second step of adding a header to the signal in a header adding circuit electrically connected to the MUX circuit, the header including information for error detection;
- a third step of protecting the signal from continuing the same date “0” to “1” in a scrambling circuit electrically connected to the header adding circuit;
- and
- a fourth step of outputting the optical transmission wave comprising the signal in a driver circuit in an optical-transmission module electrically connected to the scrambling circuit,
- wherein the driver circuit comprises:
- a differential-amplifier circuit having a pair of transistors;
- means for setting a ratio of a current flowing through one of the pair of transistors to a current flowing through the other transistor at about 1/100 or smaller by applying a higher base voltage to the base of one of the pair of transistors than a base voltage applied to the other transistor;
- and
- means for controlling the amplitude of an output current of the driver circuit by the higher electric potential applied to said base of said one of said transistors.
Dependencies are inferred from the claim text.