Ablation needle including fiber Bragg grating

An electrosurgical device, comprising:

• an electrode assembly;
• a light source configured to transmit light through an optical member at least partially disposed within a portion of the electrode assembly;
• a sensor disposed along the electrode assembly configured to measure wavelengths of light transmitted through the optical member;
• and
• a controller in electrical communication with the optical member and the sensor, the controller configured to:
• receive a first sensor signal based on a first wavelength of light transmitted through the optical member,
• transmit a control signal to an electrosurgical generator coupled to the electrosurgical device to apply electrical energy to the electrode assembly,
• receive a second sensor signal based on a second wavelength of light transmitted through the optical member;
• and
• compare the first wavelength of light to the second wavelength of light and determine a change in spacing between a plurality of segments of the optical member resulting from applying the electrical energy to the electrode assembly.

A method of measuring characteristics of an electrosurgical device, the method comprising:

• projecting light from a light source of an electrosurgical device through an optical member at least partially disposed within an electrode assembly of the electrosurgical device;
• measuring a first wavelength of light transmitted through the optical member;
• inserting at least a portion of the electrode assembly into an object such that a force is applied to the electrode assembly;
• measuring a second wavelength of light transmitted through the optical member while the force is applied;
• and
• comparing the first wavelength of light to the second wavelength of light to determine a change in spacing between a plurality of segments of the optical member resulting from the force.