| 摘要 |
PROBLEM TO BE SOLVED: To reduce an in-band crosstalk penalty in an add/drop device. SOLUTION: An optical switch includes a programmable light polarizing unit (POLCON) which receives an input optical signal and selects output signal polarization in response to a control signal. A polarizing beam splitter(PBS) splits the polarized signal selected from POLCON into 1st and 2nd orthogonally polarized signals. A feedback circuits couples a feedback signal presenting optical signal intensity of at least one orthogonally polarized signal with POLCON, and the POLCON uses it for adjusting the output signal polarization. The optical switch can be used with the input optical signal containing fixed or varying polarized light by using a single or two feedback signals. The optical switch is used a an optical add/drop unit, or can be included as a part of a wavelength division multiplexing(WDM) signal add/drop unit. |
