M. Nisa Khan

IEM LED Lighting Technolgogies · R&D and Consulting

Testimonies from LED lighting sufferers are presented. For existing research studies, the readers should look at the archives from National Library of Medicine.

I am writing this letter on behalf of Marie Johnson who is suffering epileptic seizures when exposed to LED lights. Light Emitting Diodes emit light from a flat chip, causing the cones of light to overlap which creates a spatial light distribution profile that overloads Marie's central nervous system. The purpose of this letter is to explain why LE...

Thank you for sending this Newsletter with very many pertinent facts and information encompassing 5G EMR or any notable wireless radiation causing harm to biological species including us. While I'll contact Ms. Kathleen Prlich, ESQ to add my support to stop 5G deployment in order to urgently protect the health of our nation, I am reiterating some o...

An introduction is provided for my work on wireless antennas. It includes how I got started with this work in 2020 and why I generally knew the behaviors of a flat, finite wireless antenna. Additional scientific work will be added to this project demonstrating the reasons for why a flat, finite wireless antenna produces peaked radiation intensity i...

At the suggestion of the EiC of the IEEE Journal of Microwaves, I represented the history of my manuscript regarding the rejections from other IEEE microwave journals along with my rebuttals of all objections from past peer-reviewers. He told me to come clean. I couldn't be any more forthcoming about how prior IEEE journals handled my manuscript wi...

We derive novel closed-form analytic functions for the near-field electromagnetic (EM) spatial power density distributions for flat or patch antennas. Our derived functions enable us to analytically describe how the EM field generated from such antennas propagates in space, allowing us to quantify the radiation power density at any point in space....

Thank you for writing back. I don't think a single paper like ours is going to make communication engineers claiming to know antenna theory understand that a single set of equations like Maxwell's Equations or the EM wave equation cannot describe the aggregate wave that gets formed in space for a particular finite radiation structure. Grasping Equa...

The recent outbreak of the SARS-CoV-2 novel coronavirus has devastated billions of human lives around the world by rapidly infecting people with the COVID-19 disease and threatening to infect millions more if not contained via strict isolation measures. While the cause for the virus germination is not yet clear, its physical characteristics can be...

The recent outbreak of the SARS-CoV-2 novel coronavirus has devastated billions of human lives around the world by rapidly infecting people with the COVID-19 disease and threatening to infect millions more if not contained via strict isolation measures. While the cause for the virus germination is not yet clear, its physical characteristics can be...

The recent outbreak of the SARS-CoV-2 novel coronavirus has devastated billions of human lives around the world by rapidly infecting people with the COVID-19 disease and threatening to infect millions more if not contained via strict isolation measures. While the cause for the virus germination is not yet clear, its physical characteristics can be...

The recent outbreak of the SARS-CoV-2 novel coronavirus has devastated billions of human lives around the world by rapidly infecting people with the COVID-19 disease and threatening to infect millions more if not contained via strict isolation measures. While the cause for the virus germination is not yet clear, its physical characteristics can be...

We derive the near-field light intensity distributions of an inorganic LED on its surface and in volumetric space. Our closed-form solution for 3D intensity distribution for a finite-size LED is consistent with Lambert’s Cosine Law, which provides the 3D intensity distribution for an infinitesimal, flat light source. We also derive the formula for...

The paper added here is the same paper I published in ResearchGate. The reader should know that this paper was peer-reviewed many, many times and rejected because the peer-reviewers don't understand advanced calculus, analytic geometry and photometric parameters such as luminance and luminous intensity. I have also provided 8 rebuttal documents of...

Glare and blue light from LED-based lamps have raised great concerns for medical professionals around the world. Addressing them requires accurate quantification of luminous intensity distribution (LID) generated by LEDs. For the first time, we demonstrate why inorganic LED chips including a phosphor coating produce non-uniform luminance, high peak...

This document is a continuation of Part I through Part VII published on June 3, 2019, June 5, 2019, June 10, June 12, June 17, June 21, and July 15, 2019 respectively. The prior parts contained the reviews from 3 OSA Journals where OSA’s Applied Optics reviewed my paper twice, Optical Review by the Japanese Optical Society, and the first reviews fr...

This document is a continuation of Part I through Part VII published on June 3, 2019, June 5, 2019, June 10, June 12, June 17, June 21, and July 15, 2019 respectively. The prior parts contained the reviews from 3 OSA Journals where OSA's Applied Optics reviewed my paper twice, Optical Review by the Japanese Optical Society, and the first reviews fr...

This document is a continuation of Part I through Part VI published on June 3, 2019, June 5, 2019, June 10, June 12, June 17 and June 21, 2019 respectively. The prior parts contained the reviews from 3 OSA Journals where OSA's Applied Optics reviewed my paper twice, and Optical Review by the Japanese Optical Society, for which I provided comprehens...

This document is a continuation of Part I through Part V published on June 3, 2019, June 5, 2019, June 10, June 12, and June 17, 2019 respectively. The prior parts contained the reviews from 3 OSA Journals, and Optical Review by the Japanese Optical Society for which I provided comprehensive rebuttals for each erroneous review from the reviewers an...

This document is a continuation of Part I through Part IV published on June 3, 2019, June 5, 2019, June 10, and June 12, 2019 respectively. The prior parts contained the reviews from 3 OSA Journals, and Optical Review by the Japanese Optical Society for which I provided comprehensive rebuttals for each erroneous review from the reviewers and editor...

This document contains the review from the Associate Editor of OSA Continuum Journal by OSA Publishing. The editor did not make an attempt to find any reviewers because he was convinced that I was wrong outright on a very basic mathematical problem. Sadly, his objection revealed he is very mistaken in the most basic understanding of calculus and sp...

The Optical Review Journal is by Springer and it iss overseen by Japanese optical scientists and researchers. Note that the paper this journal reviewed has a slightly different title; however, the content of this paper I wrote is essentially the same as that reviewed by OSA Journals. The reviews I received from Optical Review are also disturbingly...

This document is a continuation of Part I published on June 3, 2014. Part I contained the reviews from 2 OSA Journals for which I provided comprehensive rebuttals for each erroneous review from the reviewers and the Editor-in-Chief from OSA Continuum. Since I found those reviews to be disturbingly invalid, I decided to submit my manuscript to Optic...

Here I present the reviews and rebuttals I received from a number of OSA journals over the course of nearly 2 years. There will be more to come regarding other reviews I received and my rebuttals against them. I have given OSA editors and reviewers plenty of opportunities to correct themselves, go back to the university-level physics and calculus t...

Glare and blue light from LED-based lamps have raised great concerns for medical professionals around the world. Addressing them requires accurate quantification of luminous intensity distribution (LID) generated by LEDs. For the first time, we demonstrate why inorganic LED chips including a phosphor coating produce non-uniform luminance, high peak...

We present measurement and analysis of color stability over time for two categories of white LED lamps based on their thermal management scheme, which also affects their transient lumen depreciation. We previously reported that lumen depreciation in LED lamps can be minimized by properly designing the heat sink configuration that allows lamps to re...

We expansively investigate thermal behaviors of various general-purpose light-emitting diode (LED) lamps and apply our measured results, validated by simulation, to establish lamp design rules for optimizing their optical and thermal properties. These design rules provide the means to minimize lumen depreciation over time by minimizing the periods...

Light-emitting diode (LED) technologies are undergoing very fast developments to enable household lamp products with improved energy efficiency and lighting properties at lower cost. Although many LED replacement lamps are claimed to provide similar or better lighting quality at lower electrical wattage compared with general-purpose incumbent lamps...

http://www.amazon.com/Understanding-LED-Illumination-Nisa-Khan/dp/1466507721

An LED replacement-lamp design concept comprising tapered waveguides to provide uniform and broad light distribution is disclosed. Currently, most LED-based replacement lamps for tubular fluorescent lamps place discrete surface-mount LEDs directly on a cylindrical base, which produce wasteful, non-uniform and directional illumination unsuitable for...

Solid-state lighting (SSL), with light-emitting diodes (LEDs) as the light source, is a growing and essential field, particularly in regard to the heightened need for global energy efficiency. In recent years, SSL has experienced remarkable advances in efficiency, light output magnitude and quality. Thus such diverse applications as signage, messag...

A method for determining waveguide facet reflectivity from the electric field propagated from an optical fiber into an optical waveguide. The method determines the electric field propagated from the optical fiber into the optical waveguide by combining field terms resulting from multiple reflections occurring at an endface of the optical fiber and...

In the above-named letter [ibid., vol. 11, pp. 1129??1131, Sept. 1999] Fig. 3 was incorrect. The correct figure showing the chirp measurement at 2.5 Gb/s of the Y-branch modulator along with the data pattern is shown in the revised Fig. 3. The realtime dynamic chirp measured in frequency for the unbiased and biased ports are shown in Fig. 3(a) and...

We propose and demonstrate a novel high-speed and wavelength insensitive Y-branch modulator in InGaAsP multiple-quantum-wells that exhibits negligible chirp and is also suitable for achieving controllable chirp. We raise the refractive index on one arm via applied bias and use the unbiased arm as a modulator. As the light switches to the biased arm...

We demonstrate a novel Y-branch digital switch with a double-etch waveguide structure to greatly enhance the loss and crosstalk performance. The double-etch design increases the coupling between the two tapered Y-branch waveguides, which allows for efficient switching while decreasing the radiation loss that arises from the branching angle. This co...

A 1×2 digital optical switch in InGaAsP multiple-quantum-wells with an 8 GHz bandwidth is demonstrated, which may also be operated as a wavelength-, polarisation-, and drive-voltage insensitive modulator. The total length of the switch/modulator device is 3 mm which includes passive fan-outs for fibre interconnection. The on-chip insertion loss is...

An integrated high-speed 1×4 switch array on an InP substrate using 8 GHz Y-branch switch elements is described. This switch array is suitable for optical time division multiplexing (OTDM) and demultiplexing data at 10 Gbit/s over a wide optical bandwidth. The channel-channel isolation and insertion loss are 18 and 15 dB, respectively, which may be...

Multiple quantum well (MQW) electroabsorption (EA) modulators in InP-based materials are particularly desirable because of their low power consumption at RF frequencies near 40 GHz and beyond. These devices provide large intensity modulation under small reverse bias voltages because the quantum-confined Stark effect results in large EA near the ban...

An optical switch array in an M×N configuration has a set of M input digital optical Y-branches; a set of N output digital optical Y-branch; and at least one S-bend interconnect waveguide connecting at least one input digital optical Y-branch to at least one output digital optical Y-branch, with the S-bend interconnect waveguide being adiabatically...

Digital optical switches are very practical because they can provide flexibility for changing polarization, wavelength, temperature, and device dimensions without sacrificing crosstalk performance. For the first time, a novel compact digital optical switch in InP-based material with Gb/sec speed capability is proposed and demonstrated.

Digital optical switches (DOS) are very desirable from a practical point of view because they can provide flexibility for changing polarization, wavelength, temperature, and to some extent the device geometrical parameters, without sacrificing crosstalk performance. In this paper, a new InGaAsP-InP QW tapered Y-branch digital optical switch is prop...

We analyze and measure the electrical properties of a hybrid coplanar/ microstrip traveling-wave optical modulator containing an InGaAs/InAlAs quantum-well electron transfer structure. S-parameter measurements to 20 GHz reveal the microwave refractive index and microwave loss as a function of waveguide geometry. These experiments allow us to projec...

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We have designed and demonstrated the first semiconductor digital optical switches that use weighted-coupling Y-branches. Using the beam propagation method we model both conventional Y-branches as well as weighted-coupling, shaped Y-branches with two angles. Theoretically we find that optimal shaping of the branch can provide, for the same device l...

We demonstrate the first weighted-coupling Y-branch switch in semiconductors. The active waveguide core contains an InGaAs/InGaAlAs chopped quantum well electron transfer structure which provides large voltage-controlled refractive index changes near 1.55 /spl mu/m with high speed capability. We obtain polarization-independent switching over a wide...

The use of reflecting layers in a barrier, reservoir, and quantum well electron transfer (BRAQWET) electro-optic modulator was demonstrated to create a large optical mode (LOM) with high coupling efficiency to single mode fiber. A 1.65 dB/facet coupling loss to hyperbolically-lensed fiber in the LOM was achieved as compared to 3.0 dB/facet and 8.5...

An AlGaAs/GaAs ridge directional coupler electro‐optic modulator with a voltage‐length (VL) product of only 7.0 V mm (L=3.5 mm, V=2 V) is reported. The low VL product has resulted from the efficient electrode configuration as well as the large overlap between the optical and electrical fields in the waveguides. Propagation loss of 3.4 dB/cm and the...

A design for a velocity-matched traveling-wave directional-coupler intensity modulator in AlGaAs/GaAs is proposed. The structure utilizes a thin coating of Ta₂O₅ on the top of the modulator/electrode structure in order to achieve velocity matching between the optical wave and microwave signal. The film does not significantly a...

Optical modulators based on electrooptically-induced lateral mode interference in multimode AlGaAs/GaAs waveguides at lambda = 1.32 micron are investigated for high-frequency linear applications. The key design issue is achieving higher slope efficiency while maintaining significant linearity improvements over sinusoidal interference-based modulato...

A novel optical waveguide intensity modulator in aluminum gallium arsenide and gallium arsenide material system is modeled, designed, and experimentally demonstrated at 0.83 mum wavelength. The modulator utilizes the linear electrooptic effect in a coupled waveguide structure to achieve high extinction ratio at low drive voltage. The device structu...

We report a design of a very high frequency AlGaAs/GaAs optical modulator using a dielectric loading velocity matching technique. The optical modulator is a directional coupler which is covered with a thin coating of Ta2O5 to match the velocities of the lightwave and the rf modulating signal to within +/- 2%. The optical and rf characteristics of t...

A new design of GaAs/AlGaAs waveguide amplitude modulator intended for array applications at 830nm wavelength is reported. The device is based on polarization rotation and has bandwidths in excess of 1 GHz and an extinction ratio of 1 7dB. Mach-Zehnder modulators with 23dB have also been fabricated and arrays with 20 microns device separation fabri...

The design for a new velocity matched traveling wave directional coupler modulator (DCM) in AlGaAs/GaAs material is proposed. The DCM characteristics are compared with those of the n-i-n modulator proposed by Kim et al. ¹ and the GaAs superstate modulator proposed by Nees et al ² In this paper, velocity matching in the DCM is achieved by covering t...

The four modeling techniques compared for the eigenmode analysis of optical ridge guides are effective-index, finite-difference semivectorial, finite-element semivectorial, and vector-H formulation methods. We have written software for the effective-index and finite-difference semivectorial and Rahman and Davies’ finite-element vector-H formulation...