1



                                   CIENA CONTACT:      Suzanne DuLong
                                                       (888) 243-6223
                                                       ir@ciena.com

                                   TELLABS CONTACT:    Thomas P. Scottino
                                                       (630) 378-7504
                                                       tom.scottino@tellabs.com
                                                       www.tellabs.com

FOR IMMEDIATE RELEASE

           CIENA ANNOUNCES PRELIMINARY FISCAL THIRD QUARTER RESULTS;
          TELLABS AND CIENA REAFFIRM BOARDS' RECOMMENDATIONS IN FAVOR
                                   OF MERGER

                        CIENA CLARIFIES CERTAIN MATTERS

LISLE, ILL., AND LINTHICUM, MD. - AUGUST 14, 1998 - CIENA today announced that
it expects revenue of approximately $129 million for its third fiscal quarter
ended August 1, 1998. This compares with $121.8 million in revenue reported for
the third fiscal quarter of 1997. Net income for the quarter is expected to be
in the range of 13 cents to 15 cents per share, exclusive of one-time charges
associated with CIENA's previously announced settlement with Pirelli. This
compares with net income for the third fiscal quarter of 1997 of 34 cents per
share.

Patrick Nettles, president and chief executive officer of CIENA, said, "We
regularly face the risk of revenue fluctuation. There was an unexpected
late-quarter delay of receipt of an order of more than $25 million from an
existing customer. Additionally, we believe the anticipated change to calendar
quarter reporting resulted in some shifting of orders out of the fiscal third
quarter."

Nettles continued, "Turning to the bottom line, during the third quarter our
gross margins were impacted by price concessions offered to a large customer in
return for volume commitments. This reduced gross margins below our expected
business model for the quarter."

"It is too soon to predict the extent of the impact our continued market
penetration efforts might have on results for the balance of the year,"
concluded Nettles. "The quarter's results are evidence that until we are able
to more meaningfully diversify our customer base, CIENA's results for a given
quarter could be significantly impacted by customer mix."

                                     (more)

   2
                CIENA ANNOUNCES PRELIMINARY FISCAL THIRD QUARTER
                      RESULTS/August 14, 1998/Page 2 of 3


"We knew going into this merger that CIENA's business does not come without
risks and short-term volatility," said Tellabs President and CEO Michael J.
Birck. "We continue to believe in the long-term, strategic value of this
transaction. CIENA's optical products and expertise, coupled with Tellabs'
array of existing and pending transport products and systems, comprise a
formidable product base that far outweighs short-term revenue and earnings
variations. And despite CIENA's fiscal third quarter shortfall, we believe that
our earlier guidance regarding third and fourth quarter results for the
combined company remains appropriate."

The Boards of both companies, meeting separately this week, reaffirmed their
unanimous recommendations in favor of the merger.

Assuming the merger is approved on August 21, 1998, and closed shortly
thereafter, the combined company expects to report results for the calendar
third quarter in either the third or fourth week of October.

AT&T CLARIFICATION

CIENA also noted that, as previously reported on the proxy material relating to
the proposed merger, AT&T has indicated that it has determined not to deploy
CIENA's 16-channel DWDM. This does not exclude the possibility that AT&T would
deploy other 16-channel or higher-capacity systems. CIENA is not aware to what
extent AT&T will do so.

                                     # # #

CIENA (NASDAQ: CIEN) is a leader of open architecture, dense wavelength
division multiplexing systems for long-distance and local exchange carriers.
Through its Alta subsidiary, CIENA also provides a range of engineering,
furnishing and installation (EF&I) for telecommunications service providers in
the areas of transport, switching and wireless communications.

Tellabs designs, manufactures, markets and services voice and data transport
and access systems. The company's products are used worldwide by the providers
of communications services. Tellabs, Inc., stock is listed on the Nasdaq Stock
Market (TLAB).

                                     (more)

   3
                CIENA ANNOUNCES PRELIMINARY FISCAL THIRD QUARTER
                      RESULTS/August 14, 1998/Page 3 of 3


NOTE TO INVESTORS 

Forward-looking statements in this release are based on information available
to both companies as of the date hereof. The actual results of CIENA or Tellabs
could differ materially from those stated or implied by such forward-looking
statements, due to risks and uncertainties associated with their respective
businesses, which include among others, dependence by CIENA on its major
customers and their spending patterns and competition. The ability of Tellabs
and CIENA to successfully integrate operations following the merger will also
significantly impact future results. The forward-looking statements should be
considered in the context of these and other risk factors disclosed in the
Tellabs Registration Statement on Form S-4, as filed with the Securities and
Exchange Commission on July 21, 1998 and CIENA's Form 10-Q filed with the
Securities and Exchange Commission on May 21, 1998.



Tellabs and [TELLABS LOGO] are registered U.S. trademarks of Tellabs
Operations, Inc. in the United States and/or in other countries. CIENA is a
registered U.S. trademark of CIENA