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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549

FORM 4

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934,
Section 17(a) of the Public Utility Holding Company Act of 1935
or Section 30(h) of the Investment Company Act of 1940

o Check this box if no longer
subject to Section 16.
Form 4 or Form 5
obligations may continue.
See Instruction 1(b)

1.	Name and Address of Reporting Person* (Last, First, Middle)	2.	Issuer Name and Ticker or Trading Symbol				3.	I.R.S. Identification Number of Reporting Person, if an entity (Voluntary)
	Barrows, Timothy A.		Sycamore Networks, Inc. (SCMR)
	c/o Matrix Partners 1000 Winter Street, Suite 4500	4.	Statement for (Month/Day/Year)				5.	If Amendment, Date of Original (Month/Day/Year)
			12/19/02
	(Street)	6.	Relationship of Reporting Person(s) to Issuer (Check All Applicable)				7.	Individual or Joint/Group Filing (Check Applicable Line)
	Waltham, MA 02451 (City)                (State)           (Zip)		x	Director	o	10% Owner		x	Form filed by One Reporting Person
			o	Officer (give title below)				o	Form filed by More than One Reporting Person
			o	Other (specify below)

Reminder:	Report on a separate line for each class of securities beneficially owned directly or indirectly.
*	If the form is filed by more than one reporting person, see instruction 4(b)(v).

Table I — Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.

Title of Security (Instr. 3)

2.

Transaction Date (Month/Day/Year)

2a.

Deemed Execution Date, if any. (Month/Day/Year)

3.

Transaction Code (Instr. 8)

4.

Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)

5.

Amount of Securities Beneficially Owned Following Reported Transactions(s) (Instr. 3 and 4)

6.

Ownership Form: Direct (D) or Indirect (I) (Instr. 4)

7.

Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

Amount

(A) or (D)

Price

Common Stock

100,818

I

Partnership (1)

Common Stock

1,707,845

D

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Table II — Derivative Securities Acquired, Disposed of, or Beneficially Owned   (e.g., puts, calls, warrants, options, convertible securities)

1.

Title of Derivative Security (Instr. 3)

2.

Conversion or Exercise Price of Derivative Security

3.

Transaction Date (Month/Day/Year)

3a.

Deemed Execution Date, if any (Month/Day/Year)

4.

Transaction Code (Instr. 8)

5.

Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)

Code

V

(A)

(D)

Non-Qualified Stock Option (right to buy)

$2.90

12/19/02

A

30,000

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Table II — Derivative Securities Acquired, Disposed of, or Beneficially Owned — Continued (e.g., puts, calls, warrants, options, convertible securities)

6.

Date Exercisable and Expiration Date (Month/Day/Year)

7.

Title and Amount of Underlying Securities (Instr. 3 and 4)

8.

Price of Derivative Security (Instr. 5)

9.

Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10.

Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11.

Nature of Indirect Beneficial Ownership (Instr. 4)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

12/19/02

12/19/12

Common Stock

30,000

90,000

D

Explanation of Responses:

(1) By Matrix V Entrepreneurs Fund, L.P. Affiliated partnership under common control. The reporting person disclaims beneficial ownership of the securities indicated to the extent to which such person does not have an actual pecuniary interest in such securities. The reporting herein of such securities shall not be construed as an admission that the undersigned is the beneficial owner of any such securities for purposes of Section 16 of the Securities Exchange Act of 1934 or for any other purpose.

\s\ Timothy A. Barrows	12/20/02
**Signature of Reporting Person	Date

**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

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