Transmission interface and transmitter
The transmission interface includes a plurality of transmitters, wherein the transmitters are provided with: a power supply terminal shared by the plurality of transmitters, configured to receive a ground voltage; a bias terminal configured to receive a bias voltage; signal terminals configured to receive a signal voltage; a power supply fluctuation inverting bias unit to which a ground voltage and a bias voltage are applied, and which outputs the ground voltage making its fluctuation 180 degrees out of phase; a modulation unit to which the output of the power supply fluctuation inverting bias unit and a signal voltage are applied, and which outputs the opposite phase ground voltage making its fluctuation in phase; and a laser diode to which the ground voltage and the output of the modulation unit are applied.
1 . A transmission interface comprising:
a plurality of transmitters, each of the plurality of transmitters comprising:
a power supply terminal which is common to the plurality of transmitters, and configured to receive a first voltage;
a bias terminal configured to receive a second voltage;
a signal terminal configured to receive a signal voltage;
a power supply fluctuation inverting bias circuit to which the first voltage and the second voltage are applied, the power supply fluctuation inverting bias circuit being configured to make a fluctuation in the first voltage in opposite phase and output an inverted-phase fluctuation in the first voltage;
a modulating circuit to which the output of the power supply fluctuation inverting bias circuit and the signal voltage are applied, and configured to output an output which corresponds to the signal voltage and in which the fluctuation in the first voltage is superimposed in phase; and
a laser diode to which the first voltage and an output of the modulating circuit are applied, wherein
the power supply fluctuation inverting bias circuit includes
a resistor having a terminal connected to the power supply terminal, and
a fluctuation inverting transistor having a source connected to ground, a drain connected to the other terminal of the resistor, and a gate receiving the second voltage and the inverted-phase fluctuation in the first voltage; and
the modulating circuit includes
a modulating resistor having one of the ends connected to ground; and
a modulating transistor having a gate connected to the other end of the resistor and the drain of the fluctuation inverting transistor, a source connected to ground, and a drain connected to the other end of the modulating resistor, and configured to output the output of the modulating circuit.
2 . The transmission interface according to claim 1 further comprising:
a power supply fluctuation conveying circuit connected to the power supply terminal;
a fluctuation cut-off circuit connected to the bias terminal; and
an input circuit connected to the signal terminal, wherein
the power supply fluctuation conveying circuit and the fluctuation cut-off circuit are connected to the gate of the fluctuation inverting transistor; and
a drain of the fluctuation inverting transistor and the input circuit are connected to the gate of the modulating transistor.
3 . The transmission interface according to claim 2 , wherein the input circuit comprises:
a capacitance circuit connected between the signal terminal and the gate of the modulating transistor; and
a termination load connected to an input terminal of the capacitance circuit.
4 . A transmitter comprising:
a transmission interface comprising a plurality of transmitters, each of the plurality of transmitters comprising:
a power supply terminal which is common to the plurality of transmitters, and configured to receive a first voltage;
a bias terminal configured to receive a second voltage;
a signal terminal configured to receive a signal voltage;
a power supply fluctuation inverting bias circuit to which the first voltage and the second voltage are applied, the power supply fluctuation inverting bias circuit being configured to make a fluctuation in the first voltage in opposite phase and output an inverted-phase fluctuation in the first voltage;
a modulating circuit to which the output of the power supply fluctuation inverting bias circuit and the signal voltage are applied, and configured to output an output which corresponds to the signal voltage and in which the fluctuation in the first voltage is superimposed in phase; and
a laser diode to which the first voltage and an output of the modulating circuit are applied;
a first power supply connected to the power supply terminal;
a second power supply connected to the bias terminal; and
a plurality of signal sources respectively connected to the signal terminals of the plurality of transmitters, wherein
the power supply fluctuation inverting bias circuit includes
a resistor having a terminal connected to the power supply terminal, and
a fluctuation inverting transistor having a source connected to ground, a drain connected to the other terminal of the resistor, and a gate receiving the second voltage and the inverted-phase fluctuation in the first voltage; and
the modulating circuit includes
a modulating resistor having one of the ends connected to ground; and
a modulating transistor having a gate connected to the other end of the resistor and the drain of the fluctuation inverting transistor, a source connected to ground, and a drain connected to the other end of the modulating resistor, and configured to output the output of the modulating circuit.
5 . The transmitter according to claim 4 wherein the transmission interface further comprises:
a power supply fluctuation conveying circuit connected to the power supply terminal;
a fluctuation cut-off circuit connected to the bias terminal; and
an input circuit connected to the signal terminal, wherein
the power supply fluctuation conveying circuit and the fluctuation cut-off circuit are connected to the gate of the fluctuation inverting transistor; and
a drain of the fluctuation inverting transistor and the input circuit are connected to the gate of the modulating transistor.
6 . The transmitter according to claim 5 , wherein the input circuit further comprises:
a capacitance circuit connected between the signal terminal and the gate of the modulating transistor; and
a termination load connected to an input terminal of the capacitance circuit.
7 . A transmitter comprising:
a power supply terminal configured to receive a first voltage;
a bias terminal configured to receive a second voltage;
a signal terminal configured to receive a signal voltage;
a power supply fluctuation inverting bias circuit to which the first voltage and the second voltage are applied, the power supply fluctuation inverting bias circuit being configured to make a fluctuation in the first voltage in opposite phase and output an inverted-phase fluctuation in the first voltage;
a modulating circuit to which the output of the power supply fluctuation inverting bias circuit and the signal voltage are applied, and configured to output an output which corresponds to the signal voltage and in which the fluctuation in the first voltage is superimposed in phase; and
a laser diode to which the first voltage and an output of the modulating circuit are applied, wherein
the power supply fluctuation inverting bias circuit includes
a resistor having a terminal connecte to the power supply terminal, and
a fluctuation inverting transistor having a source connected to ground, a drain connected to the other terminal of the resistor, and a gate receiving the second voltage and the inverted-phase fluctuation in the first voltage; and
the modulating circuit includes
a modulating resistor having one of the ends connected to ground; and
a modulating transistor having a gate connected to the other end of the resistor and the drain of the fluctuation inverting transistor, a source connected to ground, and a drain connected to the other end of the modulating resistor, and configured to output the output of the modulating circuit.
8 . The transmitter according to claim 7 , wherein the power supply terminal is common to a plurality of transmitters.
9 . The transmitter according to claim 8 wherein the transmitter further comprises:
a power supply fluctuation conveying circuit connected to the power supply terminal;
a fluctuation cut-off circuit connected to the bias terminal; and
an input circuit connected to the signal terminal, wherein
the power supply fluctuation conveying circuit and the fluctuation cut-off circuit are connected to the gate of the fluctuation inverting transistor; and
a drain of the fluctuation inverting transistor and the input circuit are connected to the gate of the modulating transistor.
10 . The transmitter according to claim 9 , wherein the input circuit further comprises:
a capacitance circuit connected between the signal terminal and the gate of the modulating transistor; and
a termination load connected to an input terminal of the capacitance circuit.