Doctor of Philosophy Confirmerment

Finally I get to wear the hat....

Images I took using Scanning Electron Microscopy (SEM), showing a bug with silvery looking hair which amazingly the colour is structural and not pigment as your eyes could suggest and the focused image showing many lenses in the eye of the bug. one eye could contain hundreds of the small 25 micron wide hexagonal shaped lenses, that serve both for sight and camouflage as the facets have anti-reflection properties. so next time before you swat a fly think how complex it is and what we could benefit from understanding their structures.

Life Post Doctorate

Life used to be revolving around experiments and analysis of the endless data. Experiments that were done so many times just to get consistent data and repeated over and over such that there was no distinction of weekdays or weekend, they were just days gone by. Saturday and Sunday morning till late in the evening at Lab was a norm. Good times travelling to conferences internationally..I remember a rice bowl in Hiroshima Japan was very tasty. Chicken in Bronx USA was delicious as well as the smokin cough enducing Sizzler at Ceasers Restaurant in Dubai. Weeks went by and months climbed down as fast as we started. I am glad those days are over and a new chapter in my life is about to begin. I love doing research and will continue doing physics as it most interesting to me. It gives the true meaning of life.

I HAVE JUST PASSED MY PhD VIVA

No words can describe how i feel right now...I have just completed my PhD by passing my VIVA exam..I look back where the journey started, I can vividly remember those days, and now standing up as a Doctor of Philosophy in Quantum Physics. Thanks to all people who helped me along this journey...

Coming from Pemba Island

Sweet smells of dried cloves permeates the fresh air in this paradise island of Pemba, in East African coast..unpolluted in all sense. From warmth of the indigenous people to the soothing drink of coconut juices. Wild echoes of bush babies at night and ever closer clear sky full of brightly shinning stars. An experience words cannot conjure the essence of the natural beauty... I long to visit again soon...

Good things come to those who wait...

Looking back to catch a glimpse of my past, brings joy and reminders of what is to be done. Life is a gift to treasure and fulfill the promises left undone.For I have found a new motivation to finish what i started three years ago. To be a better person is to understand and appreciate the whole entity of being alive and appreciate the wonders of all creations. From a pebble in a lonely river bed to the sand on a deserted beach to the biggest star in the universe to the massive galaxies floating by and the lonely light travelling ever forward over billions of years. For that you will catch a glimpse of the creator.

I am Almost There

Almost there, as the printer spews out papers full of incorrigible writings, i can feel that I am almost there........and May God Bless me.. 0ne hour later .....I have just submitted my thesis..a part of me feel relieved while i know the battle has just begun for my defense.....

Reflections on past few months

I hope to finish my PhD soon as i wait for the finishing touches to be added and eventually defend my work on this vast field of quantum physics. I have worked on various devices from quantum well to quantum dot laser devices, and i have learnt as much as i could to understand their behavior. I have met very interesting people along the way and especially Prof. Emeritus Alf Adams whose contribution in semiconductor lasers is undeniably most important in the last 3 decades. Monday 27 we will be going to Royal Society of London to attend his presentation along with dignitaries and royals. So not bad choice at all to embark on this journey to understand the Physics of everything.

Finally Thesis is submitted

After a long period of sleepless nights and very tiring long hours, the work is 80% done.. the thesis is submitted and hopefully will come back with positive review. This signify the importance of the journey i started 3 years ago...i can happily say i am almost there. Definitely i know that i belong to quantum physics and i will take all efforts within my power to use the knowledge for the benefit of my people. Even though Africa has not acknowledge my presence but i am sure that i belong to the group of few who should stand and rise with Africa in technological advances. through my presentation of my work in different continents i noticed that handful of people are of African origin in these advanced science international conferences. it does not mean that Africa does not have universities pursuing advanced technologies rather their participation is almost unknown. Next job for me will be pionering the activation of African intelectuals to fully participate in the global community of advanced science.....

Reflection on past years

I should Thank Almighty God for all opportunities and missed-opportunities that came my way over the past years. for sure nothing happens in this world or this universe without a reason.

Amazing Bugs and their complex structures

Images I took using Scanning Electron Microscopy (SEM), showing a bug with silvery looking hair which amazingly the colour is structural and not pigment as your eyes could suggest and the focused image showing many lenses in the eye of the bug. one eye could contain hundreds of the small 25 micron wide hexagonal shaped lenses, that serve both for sight and camouflage as the facets have anti-reflection properties. so next time before you swat a fly think how complex it is and what we could benefit from understanding their structures.

KTA (Knowledge Transfer Account)..

Thank God, I am almost there...I have been busy writing up my three years in PhD life...I thank God for blessing me with a job before i submit my thesis..I will be working as Research Fellow for knowledge transfer between the University and one of the leading companies in 3D technologies. enhancement of 3D stereoscopic for real life application is now my focus.....it is all about circularly polarised light and little bit of brain manipulation.....

The secrets of Wet Etching on III-V Semiconductor materials

Wet etching is a fine tuned art of removing layers of materials from substrates or devices when milling using Focused Ion Beam (FIB) is not an option.

When FIB is used to make trenches on a laser device, some of the Gallium (Ga) ions are deposited on the face of trenches as the depth of milling is increased. This can compromise the characteristics of the device such that you may turn a diode into a resistor.

To remove the deposition of unwanted debris from the side walls of your trenches wet etch can be very useful. Timing in wet etching is everything otherwise you might end up losing the whole device.

Pictures taken using Scanning Electron Microscopy (SEM) are showing the effect of wet etch before and after the process. Cleaner surfaces can be seen after wet etching.

Success on Gain Measurements

For a couple of months i have been working on a project to develop new method to measure laser gain. i am happy to announce that i have been successful and the method works..watch out for papers that will be published soon on American Physics Letters (APL) or Journal of Quantum electronics (JQE).....

The Formation of Galaxies and Invisible Energy that Expand the Universe

I have observed most fascinating phenomenon of how the early galaxies came to be and how important is the expansion of the universe and saw horrible end of it. I will be recording this simple experiment to demonstrate how the early galaxies formed and show why they are flat (wafer thin) and how we all depend on the expansion of the universe for our very existence. I observed that for this universe to be what it is, factors which had to be precise were responsible and not random flactuation of conditions in time and space as many tend to base their arguments.

We know that universe is expanding but we are not clear how and what causes its expansion but one thing is sure without this expansion we would not have existed because soon after Big Bang everything would have clumped together form one massive structure which in short time would have reduced to singularity and hence no universe no solar system no earth and no people.

One scary thing is if this expansion force or energy is removed the folding up of the universe to singularity would be of sudden for this expansive entity it is the time and space controller..

Kramers Kronig Dispersion Relations and MZ Modulator

Wavelength detuning in MZ modulator is important parameter as the change in Index of Refraction depend on absorption coefficient change alpha. The larger detuning leads to larger loss due to alpha change from Kramers Kronig Relation. If the absorption peak is situated further away from operating wavelength, the change of refractive index is small and hence need larger voltage for sufficient pi phase shift. We can use absorption measurements and Reflectance measurements to calculate the real part of refractive index and the phase. this will enable us to find optimum parameters for the devices.Refractive Index change is highly polarised due to its dependence on change in Alpha which is the transition between electron state E1 and heavy holes state HH1 tends to be TE polarised. The change in refractive index is due both QCSE and Pockels effect even though Pockels effect is in the order of magnitude smaller compared to QCSE effect nonetheless not negligible when the detuning is much larger than 160nm.

Electro-absorption vs Mach-Zehnder Modulators

Probably, i have already talked about modulators, as the speed and bandwidth drives the technology ever forward i will just introduce two types of modulators used in optic networks. Electro-absorption modulators exploit the properties of materials under the influence of electric field to modulate the light carrying signals by absorption.
This type of modulators have a drawback for having a limit to how fast you can modulate light due to material properties especially the incumbent InGaAsP where valence band offset limit the depletion of holes.
Mach-Zehnder modulators uses intensity modulation where by a pi phase change between the path length leads to modulation of light. We can also use the QCSE effect to improve the Mach-Zehnder by reducing Voltage needed to change phase to pi we can use Kramers-Kronig relation to calculate the effect of absorption coefficient change on refractive index.

Back to Uni with tales from Caswell

As i pack my belongings for my journey back to University after 3 Months of placement at work i feel overcomed by sheer joy of achieving my goals at Caswell.

I know I will miss cycling back and forth to work through beautiful countryside scenery, I believe the images of farms are vividly emblazoned in my mind. I bade good bye to my adopted team of beautiful people and head for the train station at Milton Keynes. The birds who without fail woke me up early in the morning with their sweetest songs will be servely missed and whiff of manure that permiated the air as i cycle through narrow roads on the hills will be remembered always.

the hope that experience gained at Oclaro is weighs heavily in my mind on how to translate my knowledge into sustainable means of income.

I am glad i saw the other side of real world application of my academic knowledge.

Now i am looking forward to wrap up and finish my studies (GW). Surrey here i come......

InGaAsP versus InGaAlAs

Most of semiconductor devices used in optical communication networks are made of InGaAsP material. It has since became obvious that devices made of InGaAsP have lower performance due to high thermal sensitivies of this material. Huge effort to find material that will replace the incumbent InGaAsP has been deployed.

Thermal sensitivity of InGaAsP is written in its band structure. It has smaller conduction band-offset allowing thermally activated carriers to escape easily into barriers, and larger valence band offset inhibiting quick carrier emptying. There are many suitable candidates one of them being InGaAlAs which have larger conduction band offset and smaller valence band offset compared to InGaAsP. The race to depose the incumbent InGaAsP is on with new exotic materials such as dilute Nitrides, Bismides and many more...

A Trip to Natural History Museum in New York

As the Snow mountains melt in New York, i headed for the Natural History Museum from Columbus Avenue, just as stone throw to the museum. Large crowd amassed outside ready to get in..People from different nations and ages gathered outside in the morning chill from very cold breeze blowing from the Central Park across the road.

"How Much is the fee to get in", i asked the lady in uniform at the reception desk.

"Well the entry is by donation you can pay any amount but preferred amount is this much for adults and this much for kids".

I pulled out 10 bucks and she asked "how much you want pay", I felt that was enough for everything i was about to see in this vast building with vast collection of different artefacts..the hours came and went while i was gazing at amazing exhibits and never felt the urge to go back to the Broadway Street.