News from the PhiNet lab


Our first coupling into a waveguide

29th Jan, 2016.

On Friday we managed to couple 854 nm light into a buried waveguide in one of the conversion crystals from HC Photonics! Specifically, after a lot of alignment we got about 50%, of the light that we sent in, out the other side. By translating the crystal we could couple light into all 9 waveguides on the chip, and in each case observed input/output efficiencies of about 45%. We expect more when using anti-reflection-coated coupling optics.

The top picture shows the setup for free-space coupling (translation stages + aspheric lenses + oven with crystal inside). The bottom picture shows a happy martin, next to a monitor showing the image from a cheap CCD camera (silicon) looking at the output of the chip. A small bright spot is a guided 854 nm mode coming out of the waveguide. Next we have to couple 1.9 micron light into the guide at the same time, to look for the difference frequency conversion process!

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Buried waveguide chips arrived

Jan 15th, 2016.

Our buried proton-exchange waveguide chips for photon conversion have arrived from HCP. We have two, they are a little more than 50 mm long. Each chip has 9 waveguides, localised in 3 groups of 3. They material is Lithium Niobate. A link to the 'instruction manual' and company characterisation will be given here later! Here is a low-res photo taken with my mobile phone. The light is just right in the middle to resolve some of the waveguides. The anti-reflection coatings can also be seen at the ends of the chip (for 854, 1550 and 1900 nm).

The bottom photo on the right shows a microscope image of one of the two 'dummy' chips that we were also sent. The nine waveguides and serial numbers are visible.

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 New optical table delivered

December 23rd, 2015.

Our third optical table has arrived and has been installed in our lab! This plan is for this table to support our CQED ion trap system, so we hope it is good at keeping out vibrations! Thanks to the guys from the workshop for all the hard work: these things are heavy :-). It's a Newport 'Smart' table, with capability of being upgraded at a later date to have a more active approach to vibrtional damping, should that be required.

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Ridge waveguide chips arrived

3rd Dec. 2015.

Our two ridge waveguides have arrived from NTT Electronics. These Lithium Niobate crytals have micron-scale waveguides milled out of the top surface. They are lots of waveguides on each chip (more than ten and less than twenty). The waveguides in each chip are designed to phasematch our conversion process  (854nm to 1550nm via 1.9 microns) at a range of different temperatures (so different poling periods). Our chips are premounted (glued) on peliter-controlled stages, as shown in the photo below.

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