Tools of the trade - Vol 18 - Thorlabs - #901

Passive

Components

Collimation Packages

Optical Switches

Rackbox Systems

Since most of the optical power is located in the core and cladding holes and not in the glass, the non-linearity of hollow core fibers can be 2-3 orders of magnitude smaller than that of conventional fibers. In combination with the fact that dispersion crosses zero within the operating waveband, this makes these fibers ideally suited for the delivery of ultra-short

high power optical pulses.

This is demonstrated here for the delivery of 150 fs / 8 nJ pulses from a Ti:sapphire laser over a 1.5 m long fiber. Around

the zero dispersion wavelength the pulses leave the fiber virtually undistorted, despite the fact that the peak power

exceeds 100 kW.

Low non-linearity and anomalous dispersion at any wavelength

also makes is possible to transmit more powerful pulses in a

soliton regime²³. Peak powers of up to >2 MW have been

transmitted without causing damage to the fiber.

1) Gobel et al., June 1, Opt. Lett., Vol. 29, (11 ), 07/2004

2) Ouzounov et al., Science, Vol. 301, 09/2003

3) Luan et al., Opt. Express, Vol. 12, 03/2004

Connectors/ Termination Tools

Single-Mode Fiber

Rare Earth Doped

Single-Mode: PM

Photonic Crystal Fiber

Multimode Fiber:

Graded Index

Multimode Fiber: Step Index

Waveguide Circuits

-2 -1 0 +1 +2 picoseconds

-2-1 0+1 +2 picoseconds

100

75

50

Core size - 7 and 19 cell cores

Hollow core fibers are available in two core sizes, optimized for different application requirements:

7 cell core:

■ Larger Continuous Operating Bandwidth

■ Smaller Number of Core Modes and Parasitic Surface Modes

19 cell core:

■ Larger Mode Field Diameter

■ Lower M² of Fundamental Mode (more Gaussian-like) Resulting in Increased Coupling Efficiency to High-mode Quality Lasers and Conventional Fibers

■ Lower Attenuation

■ Lower Dispersion and Dispersion Slope

■ Lower Optical Non-linearity

■ Higher Breakdown Power Threshold

25

0

1500

1525

1550

1575

1600

1625

1650

1675

Wavelength [nm]

The graph compares typical transmission spectra for a 7 cell (HC-1550-02) and a 19 cell core fiber (HC19- 1550-01), both designed for operation at 1550 nm. The peaks in the transmission band of the 19 cell fiber are due to surface modes (modes at the boundary between core and cladding) that become degenerate in its propagation constant with the fundamental mode at certain wavelengths.

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