I am fascinated by the upcoming space laser comms systems coming out, and really have a passion for my career in space engineering. Trying to find out if RFIC can get me into space laser comms. Very interested in RFIC too.

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Hello all, trying to get insight in how to be a part of optical communications systems, particularly in the electronics/mixed signal IC design. Also think it’s really cool to be part of optical quantum computing arising from photonics IC’s / optical IC’s. I think laser comms are fascinating, I’ve just found out about optical IC design engineers, my goodness I couldn’t think of a cooler job. Yet, also not sure how niche this is, for example a google search for this only pops up 5 total jobs. If I can get into this field with RFIC, I’ll pursue an RFIC focuses masters (MSEE) and try to transition.

The neutral lenses currently available on the market with prolate anterior and posterior surfaces are the Akreos, SofPort, L161 (Bausch +Lomb, Bridgewater, New Jersey), and the CT Asphina 409M (Carl Zeiss Meditec). These do not modify corneal spherical aberration, are less sensitive to tilt than aspherical lenses, and provide better image quality than spherical IOLs.

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Some colleagues have proposed selecting the intraocular lens platform depending on the corneal asphericity to correct; others prefer to leave a residual positive spherical aberration to give greater depth of focus to patients. In patients with multifocal lenses, with special corneal or previous refractive surgery, spherical aberration becomes more important. It is well known that multifocal lenses distribute the light in several foci, which contributes to losing between 8 and 20% of the transmitted. All these lenses present a loss of contrast at different distances; it is at this point that it is important to make use of all the resources that can improve contrast sensitivity to give greater visual quality to this group of patients. For the cataract surgeon, it is important to know the corneal asphericity of patients to offer them the best possible result.

Spherical aberration is included within the high order aberrations, specifically in the group of fourth order aberrations, along with quatrefoil and secondary astigmatism. Spherical aberration generally reduces retinal image contrast and affects visual quality, especially under mesopic conditions.1

There are lenses with aspherical profiles that tolerate a greater lens offset, such as the CT LUCIA lens (Carl Zeiss Meditec). The “aspheric Zeiss optics” has a different design known as bi-sign,4 in which the IOL combines the advantages of neutral and correcting aspherical IOLs, making this lens a good choice for most patients and ideal for cases with an alpha angle greater than 0.5 mm or cases with the risk of the lens off center (Figure 5).

I’m very interested in analog electronics/IC’s, so I’m pursuing RFIC for my masters EE focus. I’ve seen a few jobs optical IC jobs where they want an anlog IC/ RFIC/ mixed signal design engineer, with just some familiarity in optics. So I may try a RFIC masters, and just take a couple optics EE courses for breadth and familiarity. Trying to seek input on if RFIC can get me into chip design for laser optical comms systems? Or would I need to do photonic electronics? I’m fascinated by the upcoming space laser comms systems coming out, and really have a passion for my career into space engineering. Trying to find out if RFIC can get me into space laser comms . Very interested in RFIC too.

5. **Photonic Electronics:** While not strictly necessary for all roles in optical communications, knowledge of photonic electronics and photonics IC design can open up specialized opportunities. If you find a strong interest in this area, you might consider pursuing advanced courses or a Ph.D. program focused on photonics.

The word “aspheric” is used to describe a surface or in this case a lens that does not have a spherical shape. In an aspherical lens, the rays of light passing through the center do not focus at the same point as the rays passing through the periphery of the lens.

In summary, pursuing a master’s degree in EE with a focus on RFIC, supplemented by optics-related courses, is a well-rounded approach. This educational background, combined with your pa

Today the goal of cataract surgery is to provide patients with the best possible quality of vision. While it is common to see patients post-cataract surgery with a visual acuity (VA) of 20/20, many patients remain dissatisfied with their quality of vision. This is due to several factors, including problems with the ocular surface, pseudophakic dysphotopsia, and optical aberrations in general.

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2. Develop a Strong Foundation: a. Gain proficiency in optical and photonic fundamentals, including wave theory, electromagnetic theory, and optics. b. Acquire knowledge in semiconductor device physics and integrated circuit design principles. c. Learn about semiconductor fabrication processes that are relevant to photonics.

Pursue a Master’s in Electrical Engineering (MSEE) with an RFIC focus for a strong foundation. Take optics or photonics courses to gain relevant knowledge. Seek internships or research opportunities in optical or photonics IC design. Network with professionals in the field. Work on projects related to optical communications during your studies. Apply for positions requiring analog IC/RFIC/mixed-signal design engineers with optics familiarity. Stay updated with industry developments. Your RFIC knowledge can be valuable for space laser comms systems too. Good luck!

The average spherical aberration of the anterior cornea surface is slightly positive (between +0.27 and +0.30 μm), remaining stable throughout life.2 The natural crystalline compensates for this positive spherical aberration, inducing a negative spherical aberration of –0.20 μm, leaving a slightly positive total aberration of +0.10 μm. Spherical aberration of the lens changes over time unlike spherical aberration of the cornea, going from negative to positive as cataracts develop. This positive spherical aberration of the cataractous lens adds to the spherical positive aberration of the cornea, impairing the visual quality of patients. Based on this concept, intraocular lenses were developed with negative spherical aberration, which simulate a young lens that compensates for the average positive spherical aberration of the cornea. Some studies suggest that it is not necessary to correct spherical aberration completely, and in fact it is recommended to leave a slightly positive residual (+0.10 μm). A study performed on pilots of the American Air Force by Grimson et al. suggests that a quantity of positive spherical aberration can be correlated with visual acuities of 20/15 or better.3 It is impossible to completely correct the spherical aberration in all our patients as there is an interaction between much more complex aberrations than a sum of the existing spherical aberration and the intraocular lens induced aberration. Nevertheless, the objective must be directed to a final low spherical aberration, which allows the patient good contrast sensitivity.

Some aspherical lenses have been designed with a prolate anterior surface (Tecnis, Johnson & Johnson Vision), a prolate posterior surface (AcrySof IQ, Alcon), or with both prolate surfaces (FineVision, PhysIOL, Liège, Belgium, and CT Asphina 509M). These give better contrast sensitivity when correcting positive spherical aberration of the cornea but generate less depth of focus than spherical lenses (Figure 4). In addition, they require a better centering, since a decentration of the optics of the lens induces other aberrations like coma. The performance of the lens depends on the pupil, and its function deteriorates in mesopic conditions.

5. Build Technical Skills: a. Develop proficiency in programming languages such as Python and MATLAB, which are commonly used for simulation and data analysis in photonics. b. Learn how to use design and simulation tools for PIC design, such as layout design software (e.g., Cadence, Synopsys).

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Getting into optical/photonics integrated circuits (PIC) design engineering requires a combination of education, skills, and networking. Photonics is an exciting and rapidly growing field that combines optics and electronics to create integrated circuits for various applications. Here are the steps to help you get started in this field:

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Naturally, the human cornea is aspheric, usually a bit more curved in the center and flattened toward the periphery; we call this form “prolate.” In a prolated cornea, the rays of light that cross the center of the cornea tend to converge or focus on a point anterior to the peripheral rays, and this aberration is called “negative spherical aberration.” In an oblate cornea, the central light rays are focused behind the peripheral rays, and this aberration is called “positive spherical aberration” (Figure 1).

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1. **RFIC for Optical Communications:** RFIC (Radio-Frequency Integrated Circuit) design can indeed be a valuable background for working in optical communications systems, especially in areas where RF and optical technologies intersect, such as satellite communications. Your experience with RFIC can be an asset in designing components of optical communication systems that involve RF aspects, such as RF front-end modules, transceivers, or signal processing for optical communications.

Obtain a relevant educational background in electrical engineering, photonics, or optics. Gain knowledge in photonics and its applications. Develop core engineering skills in circuit design and semiconductor devices. Specialize in PIC design through coursework or research opportunities. Seek hands-on experience through internships or research projects. Network with professionals and stay updated on industry advancements. Learn and use industry-standard design tools and software. Build a portfolio showcasing PIC design projects or research. Search for job opportunities in photonics, optoelectronics, or semiconductor companies. Stay curious, continuously learn, and adapt to new technologies.

Coma aberration

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Although low order aberrations (myopia, hyperopia, and regular astigmatism) have a greater impact on vision, high order aberrations also play an important role, especially in patients who are candidates for multifocal lenses. Among the high order aberrations that can be corrected with cataract surgery is spherical aberration. There are multiple intraocular lens options that can correct this aberration, but when and how we should use them is a topic of debate and research in recent years.

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1. Oshika T, et al. Influence of pupil diameter on the relation between ocular higher-order aberration and contrast sensitivity after laser in situ keratomileusis. Invest Ophthalmol Vis Sci. 2006;47:1334–8.2. Guirao A. Optical aberrations of the human cornea as a function of age. J Opt Soc Am A Opt Image Sci Vis. 2000;17:1697–702.3. Grimson JM, et al. Contrast sensitivity: establishing normative data for use in screening prospective naval pilots. Aviat Space Environ Med. 2002;73:28–35.4. Portney V. New bi-sign aspheric IOL and its application. Optom Vis Sci. 2012;89:80–9.5. Piracha AR. Using angle alpha in premium IOL screening. Cataract & Refractive Surgery Today. 2016;(3):24–25.

It is important to differentiate spherical aberration from corneal asphericity or commonly named with the Q coefficient. Both are related but different. Asphericity (Q) is a factor that tells us how much and how the cornea is peripherally flattened from the corneal apex, that is, if the cornea is prolate or oblate, while informing us of the degree of asphericity. A cornea with a Q of –0.20 is not the same as a cornea with a Q of –0.45; in both cases the cornea is prolate, but the prolaticity of the second case is greater, which means that the surface has a radius of peripheral curvature more flat than the first, and this means that it will have greater negative spherical aberration. A normal aspheric cornea has a Q factor between –0.20 and –0.45; a Q of zero would correspond to a completely spherical cornea, and a Q greater than zero corresponds to an oblate cornea, i.e., more powerful at the periphery than in the center, inducing positive spherical aberration. A hyperprolate cornea is considered to have a Q factor >0.6. Any corneal topographer nowadays will give us the Q value (Figure 2).

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1. Educational Background: a. Bachelor’s Degree: Start with a bachelor’s degree in a relevant field, such as electrical engineering, optics, photonics, or physics. Ensure you have a strong foundation in mathematics and physics. b. Master’s or Ph.D.: Consider pursuing a master’s or Ph.D. in photonics, optics, or a closely related field. This advanced education will provide a deeper understanding of the subject matter and make you a more competitive candidate.

6. Networking: a. Attend photonics conferences, workshops, and seminars to network with professionals and researchers in the field. b. Join relevant organizations and societies like SPIE (The International Society for Optics and Photonics) to connect with experts and stay updated on industry trends.

It’s fantastic to hear about your passion for optical communications systems, mixed-signal IC design, and your interest in space engineering. Your enthusiasm is a great foundation for a fulfilling career in these fields.

3. Hands-On Experience: a. Join photonics-related research projects or labs during your academic studies to gain hands-on experience with optical and photonic components and systems. b. Participate in internships or co-op programs with companies or research institutions specializing in photonics.

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Some authors do not recommend implanting multifocal intraocular lenses in patients with alpha angles greater than 0.5 mm.5 The iTrace device classifies with colors the amount of alpha angle; an angle less than or equal to 0.3 mm is green, 0.3 to 0.5 mm is yellow, and greater than 0.5 mm is red. A green alpha angle provides greater confidence that the patient will be looking through the center of the optic zone, as intended. One may consider implanting some multifocal lenses when the alpha angle is in the yellow zone. When there is an alpha angle in the red zone (>0.5 mm), the optical axis (center of the capsular bag) may not coincide with the visual axis of the patient, which may lead to a refractive surprise or an unsatisfied patient. This same principle used for multifocal lenses could be used for aspheric lenses.

3. **Mixed-Signal IC Design:** Mixed-signal design engineers are valuable in the field of optical communications because they can work on the interface between analog RF and digital signal processing components. This is crucial for the efficient handling and conversion of optical signals.

2. **Taking Optics Courses:** Considering your interest in laser communication and photonics ICs, taking optics-related courses as part of your EE program is an excellent idea. These courses can provide you with the necessary foundation in optics and photonics, allowing you to bridge the gap between RFIC and optical IC design.

4. **Space Engineering and Laser Comms:** If your goal is to work on space laser communication systems, having expertise in RFIC and mixed-signal design can be beneficial. Space laser communication systems often involve RF components for spacecraft communication and laser systems for high-speed data transmission.

The alpha angle, unlike the kappa angle (best known for its importance in refractive surgery), is the distance between the center of the limbus and the visual axis. Under normal conditions an intraocular lens will be centered within the capsular bag, and the center of the bag will be very close to the center of the limbus. The alpha angle can be measured with the Pentacam (Oculus, Wetzlar, Germany) or iTrace (Tracey Technologies, Houston) (Figure 6).

Spherical intraocular lenses increase spherical positive aberration in the eye, reducing the quality of the retinal image in most patients. There are few cases in which these lenses would be prescribed, such as in patients with hyperprolate corneas (operated with hypermetropic excimer laser). Among the lenses with positive spherical aberration are the MA60AT (Alcon, Fort Worth, Texas) with a spherical aberration of +0.14 +/–0.09 μm, the CT Spheris 204 (Carl Zeiss Meditec, Jena, Germany), and the Sensar lens (Johnson & Johnson Vision, Santa Ana, California).

4. Learn Relevant Tools and Software: a. Familiarize yourself with software used for PIC design, simulation, and modeling. Popular tools include Lumerical, COMSOL, and RSoft.

This article was first published in ALACCSA-R #24, September/October 2017, pages 10–15, and is included here with permission from ALACCSA. For more information about ALACCSA, visit www.alaccsa.com.

6. **Job Availability:** The number of job listings for optical IC design engineers can vary by region and industry demand. Keep an eye on job boards and consider networking with professionals in the field to get a better sense of job availability and potential career paths.

7. Create a Portfolio: a. Document your projects, research, and practical experience related to photonics. Having a portfolio or resume that showcases your work can be a valuable asset when applying for jobs.

In the consultation, we will find that the corneal spherical aberration varies greatly among individuals, especially in the presence of pathological corneas or modified ones by post-refractive surgery. In a myopic treatment with excimer laser, a central flattening of the cornea is induced, generating an oblate cornea, more flat in the center than in the periphery, inducing a positive spherical aberration. In contrast, a hypermetropic correction increases the central curvature of the anterior surface of the cornea, generating a hyperprolate cornea, inducing greater negative spherical aberration that may contraindicate the use of an aspheric intraocular lens, which instead of correcting would worsen the existing spherical negative aberration, deteriorating the quality of vision.