Abstract: The invention relates to a pulse shaping circuit for shaping electrical pulses driving an optical transmitter, e.g. a lased diode or an LED, and for providing electrical pulses having independently height and width-adjustable peaking at the edges thereof. The pulse shaping circuit of the present invention includes a high-pass RC filter with a differential output for providing transient electrical pulses from an input differential pulse, an adjustable voltage offset generating circuit, a differential amplifier for adjusting the width of the transient electrical pulses in dependence on the adjustable voltage offset, and a variable-gain current-steering amplifier for producing transient pulses with independently adjustable width and height.

Abstract: The invention relates to a DC offset cancellation circuit for a trans-impedance amplifier, which is typically used for converting an input current from a photodiode into an output voltage. The DC offset cancellation circuit utilizes the monitor current from a photodiode monitoring device to cancel the DC offset from the photodiode input current, enabling the conventional feedback circuit in the trans-impedance amplifier to be fully integrated.

Abstract: The invention relates to a DC offset cancellation circuit for a trans-impedance amplifier, which is typically used for converting an input current from a photodiode into an output voltage. The DC offset cancellation circuit utilizes the monitor current from a photodiode monitoring device to cancel the DC offset from the photodiode input current, enabling the conventional feedback circuit in the trans-impedance amplifier to be fully integrated.

Abstract: A trans-impedance amplifier has a front-end circuit including a transistor and collector resistor for setting the open-loop gain of the feedback circuit. The collector resistor, when connected directly to the power supply, has a secondary function of defining the current through the gain transistor, affecting second-order characteristics. A current source is added between the collector resistor and power supply providing a means by which several outside factors can be mitigated, e.g the current source can take over duties for determining/defining the current for the gain transistor, thereby enabling the choice of collector resistor for setting the open-loop gain separate from the current for the gain transistor.