AMENDMENT TO PREFERRED STOCK PURCHASE AGREEMENT

         THIS  AMENDMENT  dated  October  30,  2000  (this  "Amendment")  to the
Preferred  Stock  Purchase  Agreement (the  "Agreement")  dated July 28, 2000 is
entered into by and between  OPTICNET,  INC.,  ("OpticNet" or the "Company"),  a
Delaware  corporation  and BEI  TECHNOLOGIES,  INC. ("BEI  Technologies"  or the
"Purchaser"),  a Delaware  corporation.  Capitalized  terms used but not defined
herein shall have that meaning ascribed to them in the Agreement.

         WHEREAS,  on July 28, 2000 the Company and the  Purchaser  entered into
the  Agreement  whereby the Company  agreed to sell to Purchaser  and  Purchaser
agreed to purchase from the Company  500,000  shares of the  Company's  Series A
Preferred Stock;

         WHEREAS,  OpticNet and BEI Technologies  have agreed to enter into that
certain  Technology  Transfer  and  Distribution  Agreement  and  certain  other
agreements  related  thereto in connection  with the  distribution  of shares of
OpticNet's voting common stock to the stockholders of BEI Technologies; and

         WHEREAS,  each of the Company and the  Purchaser  now wish to amend the
Agreement to add new Section 4.11 as set forth below thereto;

         NOW,  THEREFORE,   in  consideration  of  the  mutual  representations,
warranties  and  agreements  contained  herein and intending to be legally bound
hereby, the parties hereto amend the Agreement as follows:

         1. Section 4 of the  Agreement  shall be amended to add new  subsection
4.11 thereto which shall read in full as follows:

                  4.11 Repurchase of Preferred Shares upon Change in Control for
         BEI Technologies.

                           (a)  Upon a  Change  in  Control  of  the  Purchaser,
                  defined as the occurrence of any one of the following events:

                                    (i) any consolidation or merger of Purchaser
                           with or into any other corporation or other entity or
                           person,  or any other  corporate  reorganization,  in
                           which the  stockholders of the Purchaser  immediately
                           prior to such consolidation,  merger,  reorganization
                           or  recapitalization,  own  less  than  [65]%  of the
                           surviving  entity's  voting  securities   immediately
                           after such consolidation,  merger,  reorganization or
                           recapitalization,  or any  transaction  or  series of
                           related  transactions  resulting  in the  transfer of
                           control  of in  excess  of [65]%  of the  Purchaser's
                           voting securities; or

                                    (ii)  the  sale  or  an   agreement  by  the
                           Purchaser  to sell  all or  substantially  all of its
                           assets;


                                       1.

<PAGE>


                  then OpticNet shall have the right (the  "Repurchase  Right"),
                  but not the obligation, to repurchase all or, at its election,
                  a portion of, the Preferred Shares from the Purchaser for cash
                  at the Fair Market Value thereof (a  "Repurchase")  as of such
                  date of such Repurchase (the "Repurchase Price"). "Fair Market
                  Value" shall be determined for the Preferred Shares by valuing
                  the same as an interest in a  continuing  business and without
                  taking into account any discounts or premiums  (e.g.,  lack of
                  marketability  discounts,   minority  discounts,   illiquidity
                  discounts and control  premiums).  The Fair Market Value shall
                  be  determined  by mutual  agreement  of the  Company  and the
                  Purchaser,  or by an investment bank, a nationally  recognized
                  accounting firm or third party  appraiser  (whose fee shall be
                  shared  equally by the  Company  and the  Purchaser)  mutually
                  agreed upon by the Company and the Purchaser (the "Independent
                  Appraiser").  In the event the Company and the Purchaser shall
                  be unable to mutually agree on the  Repurchase  Price or on an
                  Independent Appraiser within 30 days following delivery of the
                  Notice of Exercise  of  Repurchase  Right (as defined  below),
                  each  party  hereto  shall  choose an  independent  party (the
                  "Independent Designees"), which Independent Designees shall be
                  charged  with   selecting  and  agreeing  on  an   Independent
                  Appraiser. If such Fair Market Value is to be determined by an
                  Independent  Appraiser,  it shall be determined within 30 days
                  following  the  appointment  (by  mutual  selection  or by the
                  Independent Designees) of such Independent Appraiser.

                           (b) Within 30 days  following  a Change in Control of
                  Purchaser,  Purchaser  shall  deliver  to  OpticNet  a  notice
                  setting forth the circumstances of such Change in Control (the
                  "Change in Control  Notice").  Following  a Change in Control,
                  OpticNet may notify Purchaser of OpticNet's intent to exercise
                  its  Repurchase  Right,  as the case may be, by  delivering  a
                  notice of the exercise of such  Repurchase  Right (the "Notice
                  of Exercise of Repurchase  Right") to Purchaser within 60 days
                  of receipt of the Change in  Control  Notice.  Such  Notice of
                  Exercise of  Repurchase  Right shall provide the proposed date
                  for  closing  the  repurchase  of the  Preferred  Shares  (the
                  "Repurchase Date"),  which shall be not later than the earlier
                  of (i) 90 days following the date of such Change in Control of
                  Purchaser and (ii) 20 days  following the final  determination
                  of the  Repurchase  Price.  Purchaser  shall be deemed to have
                  received  the Notice of  Exercise of  Repurchase  Right 5 days
                  after mailing thereof by United States registered mail or upon
                  delivery  in  person  to  the  Purchaser  at the  address  for
                  Purchaser set forth in the Agreement.  On the Repurchase Date,
                  OpticNet   shall  cause  to  be  delivered  to  Purchaser  the
                  Repurchase  Price  by  certified  check  or wire  transfer  in
                  immediately  available funds against  delivery by Purchaser of
                  the  certificate(s)  evidencing  the  Preferred  Shares,  duly
                  endorsed  for  transfer  to  OpticNet  free  and  clear of all
                  claims,  encumbrances and rights of third parties. Any failure
                  by  Purchaser  to  deliver  the  Change in  Control  Notice to
                  OpticNet as required  herein  shall not  prejudice  OpticNet's
                  right to exercise the  Repurchase  Right  provided to OpticNet
                  herein by  following  such  requirements  for exercise of such
                  Repurchase Right as set forth above.


                                       2.

<PAGE>

                           (c) OpticNet may, at its election,  freely assign the
                  Repurchase  Right provided  herein,  to one or more parties in
                  whole or in part.

                           (d) From and after the date of any  Change in Control
                  of the Purchaser  until the earlier of (i) the Repurchase Date
                  or (ii) the date 120 days following the date of such Change in
                  Control,  BEI  Technologies  shall  automatically  and without
                  further  action be deemed to have granted and hereby grants to
                  OpticNet an  irrevocable  proxy to vote the Preferred  Shares,
                  and the shares of the Voting  Common Stock of the Company into
                  which the Preferred  Shares are  convertible,  as  applicable,
                  with full power of substitution therefor,  with respect to any
                  actions  which  the  holder  of the  Preferred  Shares  may be
                  entitled to vote upon under the Delaware  General  Corporation
                  Law or the California General Corporation Law, as the case may
                  be. Such irrevocable proxy is acknowledged by BEI Technologies
                  to be coupled with an interest.

         2.  Representations  And  Warranties  of the Company.  OpticNet  hereby
represents  and warrants to the  Purchaser  as of the date of this  Amendment as
follows:

                  2.1 Incorporation and Good Standing. OpticNet is a corporation
duly  incorporated,  validly existing and in good standing under the laws of the
State of Delaware.

                  2.2  Authorization.  All  corporate  action  on  the  part  of
OpticNet  necessary for the  authorization of this Amendment and the performance
of all obligations of OpticNet hereunder have been taken.

         3.  Representations  And Warranties of the Purchaser.  BEI Technologies
hereby  represents  and warrants to the Company as of the date of this Amendment
as follows:

                  3.1  Incorporation  and Good Standing.  BEI  Technologies is a
corporation duly  incorporated,  validly existing and in good standing under the
laws of the State of Delaware.

                  3.2  Authorization.  All  corporate  action on the part of BEI
Technologies   necessary  for  the  authorization  of  this  Amendment  and  the
performance of all obligations of BEI Technologies hereunder have been taken.

         4. Continuing Effect. Except as expressly amended hereby, the Agreement
shall remain and continue in full force and effect.

         4.  Counterparts.  This  Amendment  may be  executed  in any  number of
counterparts,  each of  which  shall be  deemed  an  original,  but all of which
together shall constitute one and the same instrument.

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                                       3.

<PAGE>


         IN WITNESS WHEREOF, the parties have duly executed this Amendment as of
the date first written above.

                           OPTICNET, INC., a Delaware corporation



                           By:
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                           Name:
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                           Title:
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                           BEI TECHNOLOGIES, INC., a Delaware corporation



                           By:
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                           Name:
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                           Title:
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