NUMBER BBND- 0001 INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE THIS CERTIFIES THAT PROOF Is the Record Holder of FULLY PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK, $0.001 PAR VALUE PER SHARE, OF BIGBAND NETWORKS, INC.

by BigBand Networks
March 8th, 2007

Exhibit 4.1

LOGO

Exhibit 4.1

NUMBER

BBND- 0001

INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE

THIS CERTIFIES THAT

PROOF

is the record holder of

FULLY PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK, $0.001 PAR VALUE PER SHARE, OF

BIGBAND NETWORKS, INC.

transferable on the books of the Corporation in person or by duly authorized attorney upon surrender of this Certificate properly endorsed. This certificate is not valid until countersigned by the Transfer Agent and registered by the Registrar.

WITNESS the facsimile seal of the Corporation and the facsimile signatures of its duly authorized officers.

DATED:

XXXXXXX

SECRETARY

BIGBAND

networks

BIGBAND NETWORKS, INC.

BIGBAND NETWORKS INC.

INCORPORATED

SEAL

DECEMBER 3,1998

DELAWARE

SHARES

CUSIP 089750 50 9

SEE REVERSE FOR CERTAIN DEFINITIONS

XXXXXX

VICE PRESIDENT

COUNTERSIGNED AND REGISTERED:

MELLON INVESTOR SERVICES LLC

TRANSFER AGENT AND REGISTRAR

BY:

AUTHORIZED SIGNATURE


LOGO

BIGBAND NETWORKS, INC.

The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or regulations:

TEN COM – as tenants in common

TEN ENT – as tenants by the entireties

JT TEN – as joint tenants with right of survivorship and not as tenants in common

UNIF GIFT MIN ACT–

Custodian

(Cust)

(Minor)

under Uniform Gifts to Minors

Act

(State)

UNIF TRF MIN ACT–

Custodian (until age)

(Cust)

under Uniform Transfers

(Minor)

to Minors Act

(State)

Additional abbreviations may also be used though not in the above list.

For Value received, hereby sell, assign and transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER

IDENTIFYING NUMBER OF ASSIGNEE

(PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

Shares of the Common Stock represented by the within Certificate, and do(es) hereby irrevocably constitute and appoint

Attorney to transfer the said stock on the books of the within named Corporation with full power of substitution in the premises.

Dated

XX

NOTICE : THE SIGNATURE(S) TO THIS ASSIGNMENT MUST CORRESPOND WITH THE NAME(S) AS WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR WITHOUT ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER.

SIGNATURE(S) GUARANTEED:

By

THE SIGNATURE(S) MUST BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM), PURSUANT TO S.E.C. RULE 17Ad-15.