EXHIBIT 23.3 CONSENT OF INDEPENDENT ACCOUNTANTS We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of Sycamore Netwoks, Inc. of our report dated June 4, 2000 relating to the financial statements of Sirocco Systems, Inc., a development stage company, which appears in Amendment No. 1 to the Registration Statement on Form S-4 of Sycamore Networks, Inc. /s/ PriceWaterhouseCoopers LLP Hartford, Connecticut September 7, 2000