We propose and demonstrate a wavelength tunable wavelength division multiplexing channel isolation filter based on two concatenated chirped long-period fiber gratings (LPGs). An intergrating space (IGS), deliberately introduced between the two gratings, provides an extra phase difference between the core and cladding modes. Changing this phase by heating the IGS without affecting the gratings tunes the channels. A theoretical account of the filter action is also presented and the results are found to be in excellent agreement with the experiments. Unlike the filters based on normal concatenated chirped LPGs without an IGS, the current filter shows a linear tuning over an increased spectral range.
© 2011 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: June 21, 2011
Revised Manuscript: August 2, 2011
Manuscript Accepted: August 25, 2011
Published: September 20, 2011
Umesh Tiwari, Saurabh Mani Tripathi, Krishna Thyagarajan, Mangalpady Raj Shenoy, Vandana Mishra, Subhash Chander Jain, Nahar Singh, and Pawan Kapur, "Tunable wavelength division multiplexing channel isolation filter based on dual chirped long-period fiber gratings," Opt. Lett. 36, 3747-3749 (2011)