Exhibit 99.1


Sycamore Networks, Inc. Announces 3-for-1 Stock Split

Wed, January 26 2000

CHELMSFORD, Mass., January 26, 2000 -- Sycamore Networks, Inc. (NASDAQ:
SCMR), a leader in intelligent optical networking, announced today that the
Company's Board of Directors has approved a three-for-one stock split of
the Company's common stock. The stock split will be effected in the form of
a stock dividend and stockholders of record at the close of business on
February 4, 2000 will be entitled to two additional shares of common stock
for each outstanding share of common stock held on that date. The
additional shares are expected to be distributed by the Company's transfer
agent on or about February 11, 2000 and the Company expects that its common
stock will begin trading on a split-adjusted basis on February 14, 2000.

About Sycamore Networks Sycamore Networks develops and markets
intelligent optical networking products that transport voice and data
traffic over wavelengths of light. The Company combines significant
experience in data networking with expertise in optics to develop
intelligent optical networking solutions for network service providers.
Sycamore's products are based on a common software foundation, enabling
concentration on the delivery of services and end-to-end optical
networking. Sycamore's products and product plans include optical
transport, access and switching systems and end-to-end optical network
management solutions. Contact Sycamore Networks at www.sycamorenet.com.

Except for the historical information contained herein, we wish to
caution you that certain matters, including statements about the value of
the agreement, discussed in this news release constitute forward-looking
statements that involve risks and uncertainties. The Company's actual
results could differ materially from those stated or implied in
forward-looking statements due to the number of factors, including those
risks and uncertainties discussed under the heading 'Risk Factors'
contained in the Company's Registration Statement on Form S-1 (file no.
333-84635) filed by the Company in connection with its initial public
offering and which became effective October 21, 1999 and the other reports
filed by the Company from time to time with the Securities and Exchange
Commission. Forward looking statements include statements regarding the
Company's expectations, beliefs, intentions or strategies regarding the
future and can identified by forward-looking words such as "anticipate",
"believe", "could", "estimate", "expect", "intend", "may", "should",
"will", and "would" or similar words. The Company assumes no obligations to
update the information included in this press release.

    Contact:
      Richard Williams                           Terry Adams
      Press Contact                              Investor Relations Contact
      Sycamore Networks                          Sycamore Networks
      Phone: 978-250-2909                        Phone: 978-250-3410
      richard.williams@sycamorenet.com           terry.adams@sycamorenet.com