Laser modulation controller with the use of an addition - and an amplitude modulation control tone

摘要

A laser modulation controller (10) provides laser modulation control by DC bias (54) to a laser (22) with a first control tone (32), amplitude modulating (70) a non-return to zero (NRZ) input working signal (18) to be converted to light output with a second control tone (30), detecting the first control tone from a portion of the light output of the laser (88, 26) as a third signal (58) which is proportional to laser gain, detecting the second control tone (30) from a portion of the light output of the laser as a fourth signal (60) which occurs only if the laser is being modulated in or below the lasing threshold region, and substantively combining the third (58) and fourth (60) signals to generate a fifth signal (84) for use as a control of the amplitude of the NRZ working signal (18).