Patent ID: 7853146

Claim:
An optical transmission apparatus comprising: an input port which inputs an optical signal from a line; an optical branching section which branches the optical signal into a first optical signal and a second optical signal; a delay branching line which delays the second optical signal by a delay amount and an optical multiplexing section which combines the first optical signal and the second optical signal into a multiplexed optical signal; and a pulse mask determination section which generates a pulse mask of the multiplexed optical signal by controlling the delay amount and limits acceptance of a line speed of the optical signal, wherein, when the optical signal is sent at a line speed lower than or equal to a line speed specified by a contract with a user, the pulse mask determination section causes the pulse mask not to lose its shape by controlling the delay amount and accepts an input of the optical signal, and wherein, when the optical signal is sent at a line speed higher than a line speed specified by a contract with a user, the pulse mask determination section causes the pulse mask to lose its shape by controlling the delay amount and refuses an input of the optical signal.