hi sahil singh
Double-clad fibers are an important technology in the area of active fiber optics, particularly for high-power fiber lasers and
amplifiers.There are a variety of different designs of double-clad fibers.The simplest kind of design has a circular pump cladding and
a centered core . This is relatively easy to make and use, but in this kind of fibers there are propagation modes of the inner cladding
(related to helical rays) which have hardly any overlap with the core, so that some significant part of the pump light exhibits incomplete absorption. As a result, the gain and power efficiency are compromised. To a limited extent, this problem can be solved by strongly coiling
the fiber.Double-clad fibers can also be made as photonic crystal fibers . Here, the multi mode pump core is suspended by very thin struts
in the air cladding, through which the pump light cannot escape. Such a structure can have a very high numerical aperture of at least 0.6 for the pump light; this further reduces the requirements concerning the brightness of the pump source. The thickness of the struts can be chosen such that at the same time one achieves good mechanical stability, high thermal conductivity, and minimal pump losses. Another advantage
of this type of fiber is that pump light is kept away from the protective polymer coating, avoiding any damage by absorbed pump light. The guidance of the core is achieved as in other photonic crystal fibers.
Also for simulating double clad doped fibers in optiwave system, i agree with asif bashir darthat you will require device level software of the optiwave namely optifiber. So you should first try to understand the basics of the software and try to implement your design in that software.
with regards