EXH10-20

                      Cooperation Agreement by and Between:

Sico Jena GmbH  Quarzschmelze  ("Sico"),  Goeschwitzer  Strasse 20,  07745 Jena,
Germany and FiberCore Inc. ("FCI"), 174 Charlton Road, P.O. Box 206, Sturbridge,
MA 01566 USA.

Whereas, Sico or an affiliate is a stockholder in FCI and Sico's principal owner
Mr. Walter Nadrag was the Managing  Director of FCI's subsidiary  FiberCore Jena
GmbH  ("FCI"),  the parties have agreed that it is necessary to define and agree
on the terms of a Cooperation Agreement between the parties.

Therefore, FCI and Sico have agreed to the following:

1 -      As an addendum to the August 1995  Agreement  between the parties,  FCI
         has agreed to (a) register  Sico's (or affiliate)  shares of FCI common
         stock  (605,000  shares as of the date hereof)  through a  Registration
         Statement  which  is due to be  filed  with  the  U.S.  Securities  and
         Exchange  Commission  ("SEC")  in the  near  future;  (b)  Sico  or the
         affiliate will establish an Escrow Account and deposit its FCI share in
         such  account;  (c)  after  the  effective  date  of  the  Registration
         Statement,  and in  accordance  with all  applicable  laws,  rules  and
         regulations,  the escrow Agent will sell such shares from time to time,
         and the proceeds thereof shall be deposited in the Escrow Account;  (d)
         after paying a reasonable broker's commission for such sales of shares,
         if  any,  the  Escrow  Agent  will  use  the  proceeds  of the  sale to
         mandatorily  prepay the purchase  price of machinery and equipment from
         FCJ to Sico  that is  currently  scheduled  to be paid  over 6 years in
         quarterly  installments,  all paid during 1996 or as soon as  practical
         thereafter based on the market conditions;  (f) the parties shall use a
         Net Present  Value ("NPV") to determine  the  prepayment  amount at the
         time  such  prepayments  are  made,  and  agree in  advance  (shall  be
         determined in the detailed agreements  mentioned under item 3 below) on
         the  discount  factor used to the  calculation  of the NPV;  (g) to the
         extent that the shares are sold for more than the prepayment amount for
         the machinery  and  equipment,  the excess  proceeds will remain in the
         Escrow Account which will be an interest  bearing  account;  (h) Escrow
         Agent  will  invest  such  extra  principal  amount  plus  interest  in
         appropriate  machinery  and  equipment  (the parties shall agree to the
         type of  equipment  needed  and  include  it as  part  of the  detailed
         agreement under item 3 below) and will enter into a sale and lease back
         of such  machinery  and  equipment  with  FCI for the  purpose  of Sico
         manufacturing  Wet Synthetic  Silica  ("WSS") or Dry  Synthetic  Silica
         ("DSS") and draw fiber optic  quality  tubes from such WSS or DSS to be
         used and/or  marketed by FCJ, FCI or an agreed upon  affiliate(s);  (I)
         the  terms  of such  lease  back  shall be over a 6 year  period,  paid
         monthly and the payment  shall be  determined  using the same  interest
         rate as the discount factor used in the NPV calculation  above, and (j)
         in the event that extra funds remain in the escrow account, it shall be
         applied  toward  prepayment  of rental  payment  calculated in the same
         manner as NPV for equipment.


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2        - Proceed in good faith with  drafting,  negotiating  and  executing  a
         detailed agreement which shall provide for the items enumerated herein,
         and shall contain  representations,  condition,  covenants and the like
         typical for the transactions discussed herein.

3 -      This is considered a binding agreement on the parties under the laws of
         the Federal  Republic of Germany,  and  supersedes  the addendum to the
         August 95 Agreement between FCI & FCJ related to the Purchase Agreement
         as of December 14, 1995.

Also,  please do not hesitate to contact Mr.  Siddig in the meantime to start on
drafting any further details as required.


Agreed by FCI:_____________________________          Date:  December 19, 1995
                 Mohd Aslami


Agreed by Sico:_____________________________         Date:  December 16, 1995
                 Walter Nadrag