Patent ID: 7116908
Filing Date: 2006-10-03
Classification: H04B,H04J

Abstract:
1. A method of controlling optical signal during transmission between a first unit and a second unit, comprising the steps of: transmitting a wave division multiplexed optical signal having a predetermined set of ranges of wavelengths from the first unit to the second unit; amplifying the wave division multiplexed optical signal at the first unit to generate an amplified wave division multiplexed optical signal; monitoring a first average value of a total optical strength level of at least one of the ranges of the amplified wave division multiplexed optical signal at the first unit; monitoring a first probe optical strength level of at least one of the wavelengths of the amplified wave division multiplexed optical signal at the first unit; monitoring at a second unit a second average value of a total optical strength level of the at least one of the ranges of a received wave division multiplexed optical signal from the first unit; monitoring at the second unit a second probe optical strength level of the at least one of the wavelengths of the received wave division multiplexed optical signal from the first unit; transmitting the second average value of a total optical strength level and the second probe optical strength level from the second unit to the first unit; and adjusting said amplification at the first unit so that a sum of the first average value and the second average value of the total optical strength level is substantially matched with a sum of the first probe optical strength level and the second probe optical strength level in order to substantially reduce a gain tilt and an optical signal-to-noise ratio in the amplified wave division multiplexed optical signal.