Dc-coupled laser driver with ac-coupled termination element

Abstract

An optical signal module including a driver and an optical signal module. The driver includes a differential pair configured to receive and process an input signal to create a drive signal. A modulation current source provides a modulation current to the differential pair. One or more termination resistors connected to the differential pair for impedance matching. A first switch, responsive to a first control signal, maintains charge on a charge storage device. The optical signal module includes an optical signal generator arranged between a supply voltage node and a bias current node. The optical signal generator receives the drive signal and generates an optical signal representing the input signal. A second switch is between a supply voltage node the bias current node. The second switch, responsive to second control signal, selectively establishes a short between the supply voltage node the bias current node.

What is claimed is: 
     
         1 . An optical signal generator module including a driver, the module comprising:
 a driver configured to process at least one input signal to generate a drive signal;   a first switch located between a supply voltage node and the driver, the first switch responsive to a first control signal;   a charge storage device located between the supply voltage node and the first switch;   an optical signal generator receiving the drive signal and responsive to the drive signal generating an optical signal;   a second switch associated with the optical signal generator, the second switch responsive to a second control signal to selectively short voltage across the optical signal generator through the switch;   one or more termination elements selected to impedance match the driver with the optical signal generator, the one or more termination resistors located between the supply voltage node and the driver mirror.   
     
     
         2 . The optical signal generator module of claim  9  wherein the at least one input signal is a differential input signal. 
     
     
         3 . The optical signal generator module of claim  9  wherein the charge storage device comprise a capacitor. 
     
     
         4 . The optical signal generator module of claim  9  further comprising a controller configured to generate the first control signal and the second control signal, such that when the optical signal generator is active the first switch is closed and the second switch is open, and when the optical signal generator is inactive the first switch is open and the second switch is closed. 
     
     
         5 . The optical signal generator module of claim  12 , wherein the when the optical signal generator is transitioning to an active state, the second switch is opened before the first switch is closed and when the optical signal generator is transitioning to an inactive state, the first switch is opened before the second switch is closed.