Photonic crystal membrane waveguides with low insertion losses

Abstract

We demonstrate experimentally that the fiber to fiber total insertion loss into a single-mode waveguide in a suspended photonic crystal membrane can be reduced to less than 10 dB (input, output, and propagation) without introducing any supplementary processing step (e.g., polymer deposition and etching). This is achieved through a suitable design of the waveguide end-facets minimizing the impedance mismatch and thereby the residual reflectance at the waveguide ends.

Integrable microwave filter based on a photonic crystal delay line

“…The fabricated device is 1.5 mm long and contains mode adapters 37 , as shown in Fig. 2a, owing to which the total insertion loss (minimum value at low group index) is reduced to about 7 dB (from fibre to fibre, including propagation in the waveguide and fibre/PhC coupling).…”

In- and out-coupling devices for subwavelength waveguides. Part 2

“…Диэлектрические плавно сужающиеся вол-новоды могут быть сделаны путем вытягивания разогретого оптического волокна [6], однако даже сужая тонкий волновод до субволновых размеров, невозможно достичь субволнового размера моды в силу естественного дифракционного ограниче-ния. Короткие обратные диэлектрические сужаю-щиеся секции нашли свое применение и для ввода излучения в фотоннокристаллические волноводы, где их применение позволяет снизить отражение при вводе излучения до 1% [7].…”

“…Nevertheless, even narrowing down the fiber to a subwavelength size it is not possible to reach the subwavelength size of the mode due to the natural diffraction limit. Short inverse tapers have found their application for light coupling to the photonic crystal waveguides [7]. Their application allows for reducing reflection down to 1%.…”

Enhanced gain in photonic crystal amplifiers

“…1. The coupling efficiency into the slab PC waveguide can be improved using an inverted taper, as demonstrated for a passive device by Tran et al [17]. The taper is designed to improve mode matching, and to reduce the reflection on the end-facets.…”