Fourth Amendment to Purchase and Sale Agreement and Preliminary Escrow Instructions
      dated July 27, 2005, with Pulte Home Corporation.


    Exhibit
      10.8.4

    


    FOURTH
      AMENDMENT TO

    PURCHASE
      AND SALE AGREEMENT

    AND
      PRELIMINARY ESCROW INSTRUCTIONS

    [Portion
      of DiCon Fiberoptics Inc. Land, Regatta Boulevard, Richmond,
      California]

    


    This
      Fourth Amendment to Purchase and Sale Agreement and Preliminary Escrow
      Instructions (the “Fourth
      Amendment”) is
      entered into as of July 27, 2005, between DICON FIBEROPTICS, INC., a California
      corporation (“Seller”) and
      PULTE
      HOME CORPORATION, a Michigan corporation (“Buyer”).

    


    RECITALS

    


    
      	A.  	
              Seller
                and Buyer entered into a Purchase and Sale Agreement and Preliminary
                Escrow Instructions as of February 27, 2004, a First Amendment to
                Purchase
                and Sale Agreement and Preliminary Escrow Instructions as of March
                1,
                2004, a Second Amendment to Purchase and Sale Agreement and Preliminary
                Escrow Instructions as of April 29, 2004, and a Third Amendment to
                Purchase and Sale Agreement and Preliminary Escrow Instructions as
                of
                February 27, 2005 (collectively, the “Agreement”).

            


    

    


    
      	B.  	
              Seller
                and Buyer desire to amend and restate certain provisions of the Agreement
                as provided in this Fourth
                Amendment.

            


    

    


    The
      parties agree as follows:

    


    AGREEMENT

     

    
      	1.  	
              
                Section
                  13.2.1 of the Agreement is hereby amended and restated in its entirety
                  to
                  read as follows:

              

            


    

     

    
      	
            	“13.2.1	
              Extension
                of Closing Date if City has not approved the Tentative Map.
                Buyer may elect to extend the Closing Date as provided and subject
                to the
                conditions precedent in this Section
                13.2.1.

            


    

    


    1st
      Extension: If the City has not approved the Tentative Map on or before the
      date
      of February 28, 2005, Buyer may extend the Closing Date to the date of March
      30,
      2005.

    


    2nd
      Extension:
      If Buyer has extended the Closing Date as provided under the 1st
      extension and if the City has not approved the Tentative Map on or before the
      date of March 30, 2005, Buyer may extend the Closing Date to the date of April
      29, 2005.

    


    3rd
      Extension:
      If Buyer has extended the Closing Date as provided under the 2nd
      extension
      and if the City has not approved the Tentative Map on or before the date of
      April 29, 2005, Buyer may extend the Closing Date to the date of May 31,
      2005.

    


    4th
      Extension:
      If Buyer has extended the Closing Date as provided under the 3rd
      extension and if the City has not approved the Tentative Map on or before the
      date of May 31, 2005, Buyer may extend the Closing Date to the date of June
      30,
      2005.

     

    5th
      Extension: If Buyer has extended the Closing Date as provided under the
      4th
      extension and if the City has not approved the Tentative Map on or before the
      date of June 30, 2005, Buyer may extend the Closing Date to the date of July
      29,
      2005.

    


    6th
      Extension: If Buyer has extended the Closing Date as provided under the
      5th
      extension and if the City has not approved the Tentative Map on or before the
      date of July 29, 2005, Buyer may extend the Closing Date to the date of August
      29, 2005.

    


    7th
      Extension: If Buyer has extended the Closing Date as provided under the
      6th
      extension and if the City has not approved the Tentative Map on or before the
      date of August 29, 2005, Buyer may extend the Closing Date to the date of
      September 28, 2005.

    


    8th
      Extension: If Buyer has extended the Closing Date as provided under the
      7th
      extension and if the City has not approved the Tentative Map on or before the
      date of September 28, 2005, Buyer may extend the Closing Date to the date of
      October 28, 2005.

    


    9th
      Extension: If Buyer has extended the Closing Date as provided under the
      8th
      extension and if the City has not approved the Tentative Map on or before the
      date of October 28, 2005, Buyer may extend the Closing Date to the date of
      November 29, 2005.

    


    Each
      of
      the 1st, 2nd, and
      3rd
      extensions
      is subject to the conditions precedent that, on or before the Closing Date
      as in
      effect prior to each such extension (a) Seller and Escrow Agent shall each
      have
      received from Buyer a written notice of Buyer’s election to extend the Closing
      Date, and (b) Seller shall have received from Buyer by wire transfer an
      extension payment in the amount of Twenty Five Thousand Dollars
      ($25,000.00).

    


    Each
      of
      the 4th,
      5th
      and
      6th
      extensions is subject to the conditions precedent that, on or before the Closing
      Date as in effect prior to each such extension (a) Seller and Escrow Agent
      shall
      each have received from Buyer a written notice of Buyer’s election to extend the
      Closing Date, (b) Seller shall have received from Buyer by wire transfer an
      extension payment in the amount of Fifty Thousand Dollars ($50,000.00), and
      (c)
      Seller shall have received from Buyer by wire transfer an extension deposit
      in
      the amount of One Hundred Thousand Dollars ($100,000.00).

    


    Each
      of
      the 7th,
      8th
      and
      9th
      extensions
      is subject to the conditions precedent that, on or before the Closing Date
      as in
      effect prior to each such extension (a) Seller and Escrow Agent shall each
      have
      received from Buyer a written notice of Buyer’s election to extend the Closing
      Date, (b) Seller shall have received from Buyer by wire transfer an extension
      payment in the amount of Twenty Five Thousand Dollars ($25,000.00), and (c)
      Seller shall have received from Buyer by wire transfer an extension deposit
      in
      the amount of Twenty Five Thousand Dollars ($25,000.00).

    


    The
      extension payments under this Section 13.2.1 are not applicable to the Purchase
      Price. The extension deposits under this Section 13.2.1 actually received by
      Seller shall be applied to the Purchase Price on the Close of Escrow. The
      extension payments and the extension deposits are non-refundable under any
      and
      all circumstances including, but not limited to, any termination of Buyer’s
      obligation to purchase and Seller’s obligation to sell the Purchase Property
      under this Agreement."

    


    
      	2.  	
              Except
                as amended and restated by this Fourth Amendment, all terms, conditions
                and provisions of the Agreement shall remain in full force and
                effect.

            


    

    


    
      	3.  	
              This
                Fourth Amendment may be executed by the different parties hereto
                on
                separate counterparts each of which, when so executed, shall be deemed
                an
                original but all such counterparts shall constitute but one and the
                same
                agreement.

            


    

    


    IN
      WITNESS HEREOF, the
      parties hereto have executed this Fourth Amendment as of the date first above
      written.

    


    
      	
              Seller:

            	
              Buyer:

            
	 	 
	
              DICON
                FIBEROPTICS, INC., 

            	
              PULTE
                HOME CORPORATION

            
	
              a
                California corporation

            	
              a
                Michigan corporation

            
	 	 
	
              By: /s/
                Ho-Shang Lee

            	
              By:
                /s/
                Steven Kalmbach

            
	
              Name:
                 Ho-Shang
                Lee, Ph.D.

            	
              Name:
                 Steven
                Kalmbach

            
	
              Its:
                President & CEO

            	
              Its:
                 Division
                President

            


    

    


    Acceptance
      by Escrow Holder

    


    CHICAGO
      TITLE COMPANY hereby acknowledges that it has received originally executed
      counterparts or a fully executed original of the foregoing Fourth Amendment
      to
      Purchase and Sale Agreement and Preliminary Escrow Instructions and agrees
      to
      act as Escrow Agent thereunder and to be bound by and perform the terms thereof
      as such terms apply to Escrow Agent.

    CHICAGO
      TITLE COMPANY 

    By:
       /s/
      Charlotte Martinez for Laurie J. Edwards  

    Name:
       Laurie
      J.
      Edwards

    Its: Assistant
      Vice President

    Date
      of
      Execution:  8-1-05  

    


    


    
      
        
        

      

      
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