Adaptive sampling qualification for extinction ratio control

An optical transmitter assembly comprising:

• a transmit optical sub-assembly (TOSA) including a laser and a monitor photodiode (MPD);
• and
• a laser driver assembly, comprising:
• a laser driver;
• and
• a sampling loop configured to facilitate sampling of photodiode current produced by a monitor photodiode (MPD), the sampling loop comprising:
• a low pass filter configured to receive transmit (Tx) data provided to the laser driver and to generate an output corresponding to a number of consecutive bits of a first type received in the transmit (Tx) data, the low pass filter configured to reset the output when a bit of a second type is received;
• a digital-to-analog converter (DAC) configured to output a threshold signal;
• and
• a comparator configured to compare the output from the low pass filter and the threshold signal, and to output a signal indicating when the photodiode current is to be sampled.

A method to facilitate sampling of photodiode current produced by a monitor photodiode (MPD) of an optical transmitter assembly, the method comprising:

• receiving a transmit (Tx) data provided to a laser driver of the optical transmitter assembly;
• generate an output corresponding to a number of consecutive bits of a first type received in the transmit (Tx) data,
• resetting the output when a bit of a second type is received;
• generating a threshold signal;
• comparing the output and the threshold signal;
• and
• outputting a signal indicating when the photodiode current is to be sampled.