Jinchae Kim

Photonic crystal fiber coupler

Fiber couplers made with photonic crystal fibers (PCF) are reported. Two types of PCF were fabricated by means of stacking a group of silica tubes around a silica rod and drawing them. The fiber couplers were made by use of the fused biconical tapered method. With a fiber that had five hexagonally stacked layers of air holes, a 33/67 coupling ratio was obtained, and with a one-layer four-hole fiber, a 48/52 coupling ratio was obtained. The fabrication processes and the characteristics of the PCFs and the PCF couplers are presented.

Tunable photonic crystal fiber coupler based on a side-polishing technique

A tunable photonic crystal fiber (PCF) coupler, which couples part of the optical power in one PCF with that in another PCF, has been made by side polishing. We fabricated the PCF coupler by mating two side-polished PCFs. We achieved evanescent field coupling between the core modes of the two PCFs by using side polishing to bring the cores close to each other. By adjusting the mating angle between the two side-polished PCFs we obtained as much as 90% tunability in the coupling ratio. The spectrum of the coupling ratio was almost flat, with small ripples, over a 400-nm wavelength range.

Pulse Compression using a Tapered Microstructure Optical Fiber

We calculate the pulse compression in a tapered microstructure optical fiber with four layers of holes. We show that the primary limitation on pulse compression is the loss due to mode leakage. As a fibers diameter decreases due to the tapering, so does the air-hole diameter, and at a sufficiently small diameter the guided mode loss becomes unacceptably high. For the four-layer geometry we considered, a compression factor of 10 can be achieved by a pulse with an initial FWHM duration of 3 ps in a tapered fiber that is 28 m long. We find that there is little difference in the pulse compression between a linear taper profile and a Gaussian taper profile. More layers of air-holes allows the pitch to decrease considerably before losses become unacceptable, but only a moderate increase in the degree of pulse compression is obtained.

Lensed photonic crystal fiber obtained by use of an arc discharge.

A lensed photonic crystal fiber (PCF) is proposed as an effective element for an optical free-space interconnector. By simultaneously forming a beam-expansion region and a focusing lens on a single piece of PCF, effective coupling between PCFs could be achieved. A long working distance of up to 1 mm with wide longitudinal and lateral tolerances was measured. The optical characteristics of the lensed PCFs and the connectors made from them are analyzed experimentally and theoretically.

The Fabrication of a Photonic Crystal Fiber and Measurement of its Properties

In this paper, we describe the fabrication process of a photonic crystal fiber and present the measured optical properties of the photonic crystal fiber. The fabrication of the photonic crystal fiber involves stacking, jacketing, collapsing, and drawing using a conventional drawing tower The photonic crystal fiber drawing needs higher tension to maintain the uniform air hole structure. Thus, the temperature of the photonic crystal fiber drawing is lowered by a few hundred degrees Celsius than for the case of conventional optical fiber drawing. The optical properties of the fabricated photonic crystal fiber such as mode profile, optical loss, transmission spectrum, bending loss, and polarization dependent loss are measured.

Dependence of the Transmission Characteristics of Photonic Crystal Fiber on the Macrobending Radius and the Mechanically Induced Microbending

It is reported that the spectral loss of photonic crystal fiber (PCF) having a large hole-to-hole distance (~ 10

The Optimum Fusion Splicing Conditions for a Large Mode Area Photonic Crystal Fiber

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Analysis of the dispersion properties of holey optical fibers using normalized dispersion

) is sensitive to micro- and macrobending when compared with the conventional single-mode fiber. In this paper, we will present the measurement result of the macro- and microbending characteristics of fabricated PCF with large hole-to-hole distance (> 10

Demonstration of an Ultra-Wide Wavelength Tunable Band Rejection Filter Implemented with Photonic Crystal Fiber

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An Efficient Dispersion Calculation Method for Axially Symmetric Optical Fibers

) . For the macrobending experiment, the fiber was simply wound around a circular structure with variable diameter that could be reduced to a few centimeters. For the microbending case, regularly spaced silica rods were attached on a slide glass and pressed against the fiber by loading a stack of metal plates of known weight on the glass. The transmission loss spectrum shows a rather flat response to the to microbending, and this makes the PCF a good candidate for a wideband variable optical attenuator.