Patent ID: 6516112
Filing Date: 2003-02-04
Classification: G02B,H04J

Abstract:
An optical wavelength filter, comprising:first optical means having first, second and third ports for receiving an input optical signal having a plurality of wavelength components at the first port, for directing the input optical signal to the second port, for receiving a reflected optical signal returning to the second port, and for directing the reflected optical signal to the third port; and second optical means having a fourth port connected directly to the second port of the first optical means for directly receiving the input optical signal directed to the second port and for reflecting only a predetermined wavelength component of the input optical signal received via the fourth port, said reflected predetermined wavelength component comprising the reflected optical signal returning to the second port, said second optical means having a fifth port and passing other wavelength components of the input optical signal to the fifth port; wherein the second optical means comprises a fiber Bragg grating reflection filter for making a refractive index difference with a grating period having regular intervals using light interference, and for reflecting only the predetermined wavelength component backward from a light traveling direction.