Patent ID: 7343102
Filing Date: 2008-03-11
Classification: H04B

Abstract:
1. An optical transmission system for transporting optical signals over downstream and upstream optical transmission lines, comprising: (a) a downstream optical transmission device comprising: a first optical transmission unit that receives downstream optical signals from the downstream optical transmission line, which comprises a preamplifier unit to amplify incoming optical signals, and a downstream-device variable optical attenuator disposed before the preamplifier unit to attenuate the incoming optical signals, a second optical transmission unit oriented in the opposite direction to the first optical transmission unit to transmit upstream optical signals over the upstream optical transmission line, and a downstream device controller that adjusts the downstream-device variable optical attenuator by utilizing incoming optical noise and selects and sets operating mode of the preamplifier unit during an automatic startup process; and (b) an upstream optical transmission device comprising: a third optical transmission unit that transmits the downstream optical signals over the downstream optical transmission line, which comprises a post-amplifier unit to amplify the optical signals for transmission, a fourth optical transmission unit oriented in the opposite direction to the third optical transmission unit to receive the upstream optical signals from the upstream optical transmission line, and an upstream device controller that causes the post-amplifier unit to emit optical noise and selects and sets operating mode of the post-amplifier unit, while exchanging messages with the downstream device controller over a supervisory control channel during the automatic startup process.