Patent ID: 6937788

Claim:
An optical device comprising; a. a first length of optical fiber having length L 1 , supporting at least a first core-guided mode and a second core-guided mode, b. a second length of optical fiber having length L 2 , supporting at least a first core-guided mode and a second core-guided mode, wherein L 1 and L 2 are not equal. c. first mode converter (MC) means coupled to the input of L 1 for converting light between the first core-guided mode and light in the second core-guided mode, d. second MC means coupled between the output of L 1 and the input of L 2 for converting light between the first core-guided mode and light in the second core-guided mode, e. third MC means coupled to the output of L 2 for converting light between the first core-guided mode and light in the second core-guided mode, and f. means for independently switching each of the MC means from a state that passes the core-guided modes to a state that converts between the first core-guided mode and the second core-guided mode.