Exhibit 23.3

                       CONSENT OF INDEPENDENT ACCOUNTANTS

   We hereby consent to the use in this Amendment No. 1 to the Registration
Statement on Form S-4 (File No. 333-40146) of Sycamore Networks, Inc. of our
report dated June 4, 2000 relating to the financial statements of Sirocco
Systems, Inc., a development stage company, which appears in such Registration
Statement. We also consent to the references to us under the headings "Experts"
and "Selected Historical Financial Data of Sirocco" in such Registration
Statement.

/s/ PricewaterhouseCoopers LLP

Hartford, Connecticut

August 11, 2000