Abstract: The present invention provides an optical receiver that enables to vary the sensitivity depending on the transmission speed. The optical receiver provides a photodiode to generate the photocurrent, the pre-amplifier to convert the photocurrent to the voltage signal, the lead pin to supply the bias voltage to the photodiode, and the control block to generate the switching signal for varying the current-to-voltage conversion efficiency and the frequency bandwidth of the pre-amplifier based on the control signal. The control signal is commonly provided from the lead pin through which the bias voltage is applied. The control block interprets the signal applied to the lead pin and generates the switching signal.

Abstract: The present invention provides an optical receiver that enables to vary the sensitivity depending on the transmission speed. The optical receiver provides a photodiode to generate the photocurrent, the pre-amplifier to convert the photocurrent to the voltage signal, the lead pin to supply the bias voltage to the photodiode, and the control block to generate the switching signal for varying the current-to-voltage conversion efficiency and the frequency bandwidth of the pre-amplifier based on the control signal. The control signal is commonly provided from the lead pin through which the bias voltage is applied. The control block interprets the signal applied to the lead pin and generates the switching signal.

Abstract: The present invention provides an optical receiver that enables to vary the sensitivity depending on the transmission speed. The optical receiver provides a photodiode to generate the photocurrent, the pre-amplifier to convert the photocurrent to the voltage signal, the lead pin to supply the bias voltage to the photodiode, and the control block to generate the switching signal for varying the current-to-voltage conversion efficiency and the frequency bandwidth of the pre-amplifier based on the control signal. The control signal is commonly provided from the lead pin through which the bias voltage is applied. The control block interprets the signal applied to the lead pin and generates the switching signal.

Abstract: The present invention provides an optical receiver that suppresses the saturation in the output without alleviating the bandwidth restriction of the current-to-voltage conversion gain. This optical receiver comprises an amplifier 4 for receiving a photocurrent IIN from a photodiode, and a plurality of trans-impedance elements connected in parallel between the input terminal and the output terminal of the amplifier 4. One trans-impedance element includes only resistor, while the other trans-impedance elements include semiconductor switches and resistors connected in series to the semiconductor switches so as to put the semiconductor switches therebetween.

Abstract: The present invention provides an optical receiver that enables to vary the sensitivity depending on the transmission speed. The optical receiver provides a photodiode to generate the photocurrent, the pre-amplifier to convert the photocurrent to the voltage signal, the lead pin to supply the bias voltage to the photodiode, and the control block to generate the switching signal for varying the current-to-voltage conversion efficiency and the frequency bandwidth of the pre-amplifier based on the control signal. The control signal is commonly provided from the lead pin through which the bias voltage is applied. The control block interprets the signal applied to the lead pin and generates the switching signal.

Abstract: Provided are a source follower circuit having a current source having its improved current characteristics, laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit. Each of the laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit comprises the source follower circuit. The source follower circuit 10 comprises a source follower stage 12 and a bias stage 14. The source follower stage has III-V compound semiconductor transistors 16, 18 and 20. The bias stage 14 has a first node 22 for providing a first bias voltage and a second node 24 for providing a second biasing voltage different from the first biasing voltage. The gate of transistor 16 is coupled to input 26 and a source thereof is coupled to output 28. The gate of transistor 18 is connected to the second node 24. The gate of transistor 20 is connected to the first node 24.

Abstract: Provided are a source follower circuit having a current source having its improved current characteristics, laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit. Each of the laser driving apparatus, semiconductor laser apparatus, current-voltage conversion circuit, and light receiving circuit comprises the source follower circuit. The source follower circuit 10 comprises a source follower stage 12 and a bias stage 14. The source follower stage has III-V compound semiconductor transistors 16, 18 and 20. The bias stage 14 has a first node 22 for providing a first bias voltage and a second node 24 for providing a second biasing voltage different from the first biasing voltage. The gate of transistor 16 is coupled to input 26 and a source thereof is coupled to output 28. The gate of transistor 18 is connected to the second node 24. The gate of transistor 20 is connected to the first node 24.