Back to results
US 2009/0268767 A1Published application
Dc coupled driver with active termination
AssigneeJDS Uniphase Corporation
InventorDavid A. NELSON
Life of this patent
Estimating the term…
Abstract
A DC coupled driver is described for modulating a vertical cavity surface emitting laser at high speeds with active termination. High speed and low total power dissipation is achieved by improving the driver immunity to pulse reflections, which can arise due to impedance mismatch between the driver output impedance and the VCSEL impedance. The rise and fall times of the driver may be adjusted for particular applications. The driver may be fabricated using a choice of bipolar, NMOS and PMOS technologies.
Claims17
A DC-coupled driver for driving a vertical cavity surface emitting laser (VCSEL) diode comprising:
- a first positive voltage supply for providing a supply voltage to the driver during operation;
- a ground rail for providing a current return path to the first positive voltage supply;
- a differential input stage for receiving data and complementary data signals from a signal source, the differential input stage comprising a first and a second transistor, a first and a second output terminal, each connected to the first and a second transistor, respectively, and a modulation current source for biasing the first and second transistors;
- a termination resistor having a first and a second terminal;
- a first current source connected to the first terminal on the termination resistor for providing a current bias to at least one of the VCSEL diode and the first transistor of the differential input stage;
- a low frequency differential input feedback amplifier for sensing a voltage drop across the termination resistor, and operational to maintain a predetermined voltage drop across the termination resistor;
- and
- wherein the VCSEL diode is connected directly to the termination resistor for actively controlling a driving voltage on the VCSEL diode.
5 more elements
Dependencies are inferred from the claim text.