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What I Learned About Quality From A Few Strands of Glass

Tags :

transceiver, fiber, laser, networks, quality, downtime, product testing, quality assurance, optical, fiber optics, transceivers

Category :

Quality Assurance

Created by :

Mark Holder

Cost or Quality?

The product of depression-era parents, I grew up with an emphasis on price over quality. Clipping coupons, buying on sale, always hunting for that next bargain, was a way of life. Buy cheap and save because you never knew when the next economic crisis, national or personal, might arise.


As I grew older I began to see the wisdom of buying quality, to appreciate the merits of taking the long view and saving over time due to fewer replacement cycles, less downtime and so forth.

Recently, this distinction was driven home to me quite dramatically when a work assignment called for the disassembly and photography of the inner workings of a fiber optic transceiver module.

External view of QSFP transceiver

A transceiver is a small device that contains a circuit board, a laser transmitter, a receiver and various optical/electrical conversion and wavelength filtering components. Its purpose is to transmit and receive large amounts of data along a single strand – or strands – of glass at very high speeds.


Competitor's Burned Circuit BoardIf ever there were a place that warranted high quality manufacturing practices; this would be it, right? But what I saw as I shot close-up after close-up shocked me. Burned circuit board, scorched electrical contacts, improperly placed thermal paste, horrendous workmanship throughout! What in the world was I looking at here?

As the backstory behind this project unfolded I found that this particular transceiver was from a competitor and at a price much lower than we are able to offer. Curious as to how this could be possible we purchased some transceivers from them for testing.

Scoping Out the Problem

EXFO scope showing competitor's dirty and damaged fiber ferrule.

The initial visual inspection revealed no obvious problems; the quality appeared to be fine. As damaged or dirty connectors are a primary cause of fiber network failures, the next step in testing was to examine the transceiver with an EXFO fiber scope. The close-up images produced by the scope revealed lots of debris and damage in the fiber ferrule on the transmitter and receiver optical sub-assemblies (TOSA and ROSA). To find the transceiver in such condition, right out of the box, is indicative of extremely poor handling, and perhaps even, manufacturing practices and will soon lead to problems within the network. To compare, one of our transceivers was pulled off the shelf and subjected to the same test with the same EXFO fiber scope. The difference was startling, revealing a very clean surface with no debris and no damage.

The Competition Heats Up

Next, the cheap transceiver was plugged into a switch and fired up. “Fired up” is a good phrase here as the module began to heat up, almost to the point of being unable to touch it. The final test was to disassemble the module and inspect the interior components. It was discovered that those dirty and damaged TOSA and ROSA were actually used parts, the circuit board was of a very low quality and their assembly was horrendous. It appeared to have been assembled by hand and the electrical leads on the board were almost touching at one point. Heat, of course, makes things expand, and if they heat up enough, those leads can touch one another and begin to arc, risking not only the transceiver itself, but the switch and even the entire network.

Quality Quote

A second transceiver, purchased from the same company, was also tested. Upon insertion into one of our routers it fried the port. When disassembled, it was discovered that the circuit board was badly burned in several places.

Based on these tests, the theory is that these companies are buying broken and used modules from major manufacturers, removing the high-end components, reassembling them and selling them as new parts. No wonder they can offer them at such a cheap price!

Night and Day

Side-by-side quality comparisonFor the purposes of a side-by-side comparison one of Network Distributors’ transceivers was also disassembled and inspected. The differences were immediately evident. The quality of the soldering was consistent and clean, evenly spaced, with no excess material glopped around that can become problematic at a later time.



Whether you’re shopping for fiber optics or shoes, quality is important. Why put your customers, your network – or your feet – at risk? Check under the hood, kick the tires and know what you’re buying before you buy.

When it comes to quality, Network Distributors’ CEO, Jason Colyar, sums it up nicely. “Customer downtime isn’t worth the risk of saving a few dollars up front on cheap fiber optics. You’re better off just spending the extra money ahead of time, buying from a quality source … versus taking a risk by trying to save money on the front end but getting an unknown product in the long run.”


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