Misalignment Studies in Laser Diode to Upside Down Tapered Microlens Tipped Circular Core Photonic Crystal Fiber Excitation

Abstract

By employing Gaussian field distributions for both the source and the fiber and also the
already derived ABCD matrix for upside down tapered microlens, we investigate theoretically
the coupling optics involving a laser diode emitting practically interesting two different
wavelengths either 1.3 μm or 1.5 μm, and a series of circular core photonic crystal fibers with
different air filling ratio and lattice constant via upside down tapered microlens of two
specific taper lengths on the tip of such fiber in absence and presence of possible transverse
and angular misalignments. It is observed that, for a fit taper length of 70.0 μm of upside
down tapered microlens, photonic crystal fiber with air filling ratio of 0.35 and lattice
constant of 5.0 μm comes out to be the most suitable one to couple laser diode emitting light
of wavelength =1.3m. The coupling efficiency can reach to 94.63% with simultaneous
optimization of taper length and source position of specific lensed fiber. Such analysis which
as per our knowledge is the first theoretical investigation, will be extremely important in
ongoing investigations for the design of optimum launch optics involving upside down tapered
microlens on the tip of photonic crystal fiber. Moreover, the results are extremely useful for
assessing deeply the sensitivity of such coupler with reference to above kind of misalignments.
Keywords: ABCD matrix, upside down tapered microlens, circular core photonic crystal fiber, transverse misalignment, angular misalignment

Cite this Article
Sumanta Mukhopadhyay. Misalignment Studies in Laser Diode to Upside Down Tapered Microlens Tipped Circular Core Photonic Crystal Fiber Excitation. Research & Reviews: Journal of Physics. 2018; 7(3): 85–101p.