Patent ID: 7634160

Claim:
A passive optical network system based on wavelength protection, comprising an OLT that includes a first interface circuit A and a second interface circuit B, a first trunk fiber and a second trunk fiber, an optical splitter network that is connected with the first trunk fiber and the second trunk fiber, branch fibers that are connected with the optical splitter network, and multiple ONUs P that include first interface circuits A′ and second interface circuits B′, characterized in that it also comprises: a first WDM device, one end of which being connected with the first trunk fiber, and other end being connected with the first interface circuit A through a first interface optical fiber; a second WDM device, one end of which being connected with the second trunk optical fiber, and the other end being connected with the second interface circuit B through a second interface optical fiber; and multiple WDM devices at unit side, one end of each being connected with one branch fiber, and the other end being respectively connected with the first interface circuit A′ and the second interface circuit B′ of one ONU P through two unit interface optical fibers; said first interface circuit A is used to transmit a downlink optical signal D A ; the second interface circuit B′ is used to transmit a downlink optical signal D B , wherein wavelengths of D A and D B are different; said first interface circuit A′ is used to transmit an uplink optical signal U A ; the second interface circuit B′ is used to transmit an uplink optical signal U B , wherein wavelengths of U A and U B are different; said first WDM device can pass the downlink optical signal D A and the uplink optical signal U A , but refuses the uplink optical signal U B , while said second WDM device can pass the downlink optical signal D B and the uplink optical signal U B , but refuses the uplink optical signal U A ; said optical splitter network is used to distribute optical power of downlink optical signals sent in through ports of the two trunk fibers to each port of the branch fiber, and optical signals sent in through each port of the branch fiber are super-positioned first and then output from ports of the trunk fibers; said WDM device at unit side can respectively pass the downlink optical signals D A and D B that are transmitted by the branch fiber connected with it to the first interface circuit A′ and second interface circuit B′ of corresponding ONU P, and pass the unlink optical signals that are transmitted by the two interface circuits to said branch fiber.