The following items consist of two statements, one labeled as “Assertion (A)” and the other labeled as the “Reason (R)”. You are to examine the two statements carefully and decide if the Assertion (A) and the Reason (R) are individually true and if so whether the reason is a correct explanation of the assertion. Select your answer to these items using the codes given below and mark your answer accordingly. Assertion (A): Polarization preserving fibers have a special core design that maintains the state of polarization. Reason (R): In polarization preserving fibers, there is a stress applying part, which creates slow and fast axes in the core. Correct Answer Both (A) and (R) are true and (R) is the correct explanation of (A). Explanation: Polarization maintaining fiber (PM Fiber) is a special type of single-mode fiber. Normal single-mode fibers are capable of carrying randomly polarized light. However, PM fiber is designed to propagate only one polarization of the input light. In polarization-maintaining fiber, the polarization of linearly-polarized light waves launched into the fiber is maintained during propagation, with little or no cross-coupling of optical power between the polarization modes. There are two categories of polarization maintaining fiber (PMF) available, linear polarization-maintaining fiber (LPMF) and circular polarization-maintaining fiber (CPMF). [ alt="F1 Tapesh 21.11.20 Pallavi D 9" src="//storage.googleapis.com/tb-img/production/20/11/F1_Tapesh_21.11.20_Pallavi_D%209.png" style="width: 253px; height: 241px;"> Conclusion: Both (A) and (R) are true and (R) is the correct explanation of (A). Extra concept: PM optical fibers are used in special applications, such as fiber optic sensing, interferometry, and slab dielectric waveguides PM fibers are expected to be used in coherent optical transmission systems or long-distance bidirectional optical transmission systems They may also be used in transmission applications where the polarization plane of the optical signal is important, such as transmission lines for optical sensors and coupling for optical-electrical integrated circuits PM fibers are used in lithium niobate modulators, Raman amplifiers, and other polarization-sensitive systems to maintain the polarization of the incoming light and keep cross-coupling between polarization modes at a minimum.