Source: Ciena.

Telecom-grade networking equipment maker Ciena (NYSE:CIEN) reported results for the second quarter of fiscal year 2014 this morning and shares jumped as much as 17% higher on the news.

Analysts were looking for adjusted earnings of $0.13 per share on roughly $560 million in total sales. Ciena's revenue was in line with Street projections, but earnings jumped all the way to $0.17 per share. That's up from $0.02 of adjusted earnings per share on sales $508 million in the year-ago quarter.

Non-GAAP gross margins expanded by 0.6% year-over-year, and now stand at 43.1%. Operating margins jumped 68% higher, to 6.2%.

Strong demand for Ciena's cutting-edge converged packet optical products provided the bulk of the company's growth, while commodity products in the optical transport division continued to decline.

One customer accounted for 21.5% of Ciena's total revenue. This large customer was not explicitly named in the press release, but AT&T has traditionally been Ciena's biggest buyer. Between 2011 and 2013, AT&T was the only Ciena customer to exceed 10% of the company's sales in any given year, with the ratio of AT&T sales to overall revenues ranging between 13% and 18%.

Looking ahead, Ciena expects third-quarter sales near $600 million. That would be about 3% above the current analyst view.

Ciena CEO Gary Smith hasn't changed his view from the first-quarter report's optimistic statements. "As a direct result of our expanding role and reach in the industry, we delivered strong financial results in both our second quarter and first half of fiscal 2014," Smith said in a statement released today.