Wide tuning range fiber bragg grating filter (FBGF) using muscle wire

An optical filter having a variable tuning range, comprising:

• a fiber having a selected length and a selected diameter for conducting optical signals, said fiber including a Bragg grating with a predetermined pitch for reflecting back a plurality of reflected optical signals having a selected wavelength;
• a plurality of Shape Memory Alloy (SMA) members disposed around said fiber in a longitudinal configuration, each SMA member having a length and a diameter substantially the same as the length and the diameter of said fiber, wherein the ends of said SMA members are bonded to the ends of said fiber;
• and
• a current source for supplying a controlled amount of current to said SMA members to cause a change in their length, thereby generating a corresponding change in the length of said fiber, said corresponding change in the length of said fiber causing a change in the pitch of said Bragg grating such that said plurality of reflected optical signals tune to a different wavelength.

A method of making a tunable optical filter, comprising the steps of:

• providing a fiber Bragg grating member of a selected length and a selected diameter;
• bonding a plurality of Shape Memory Alloy (SMA) members to said fiber Bragg grating member, each SMA member having a length and a diameter substantially the same as the length and the diameter of said fiber Bragg grating member, such that said SMA members are disposed longitudinally along the length of said fiber Bragg grating member and the ends of said SMA members are attached to the ends of said fiber Bragg grating member;
• and
• coupling a current source to said plurality of SMA members, wherein said current source is in a closed-loop control arrangement with an output provided by said fiber Bragg grating member such that a controlled amount of current is applied to said SMA members to cause a change in their length, thereby effectuating a corresponding change in the length of said fiber Bragg grating member.

A method of making a tunable optical filter, comprising the steps of:

• providing a fiber Bragg grating member of a selected length and a selected diameter;
• bonding a plurality of Shape Memory Alloy (SMA) members to said fiber Bragg grating member, each SMA member having a length and a diameter substantially the same as the length and the diameter of said fiber Bragg grating member, such that said SMA members are disposed longitudinally along the length of said fiber Bragg grating member and the ends of said SMA members are attached to the ends of said fiber Bragg grating member;
• and
• thermally coupling a heat source to said plurality of SMA members, wherein said heat source is in a closed-loop control arrangement with an output provided by said fiber Bragg grating member such that a controlled amount of heat is applied to said SMA members to cause a change in their length, thereby effectuating a corresponding change in the length of said fiber Bragg grating member.