Exhibit 2.1

SHARE PURCHASE AGREEMENT

BETWEEN

AVANEX CORPORATION

AND

GLOBAL RESEARCH COMPANY

AND

Mr. DIDIER SAUVAGE

28 February 2007

BETWEEN

AVANEX CORPORATION, 40919 Encyclopedia Circle, Fremont CA 9438, USA, represented by its legal representative, duly empowered for the purposes hereof,

(“Avanex Corp” or the “Seller”)

AND

Mr. Didier Sauvage, residing at 35 rue Fernand Carrière 91700 Sainte-Geneviève des Bois, France, born on 10 october 1956 in Lens (62),

GLOBAL RESEARCH COMPANY, a société à responsabilité limitée with a share capital of EUR 1,248,690, having its registered offices at 66 avenue de New York 75116 Paris, France, registered under number 414 434 068 RCS Paris, represented by Alexandre Krivine, its manager,

(together, the “Purchaser”)

Each of the Seller and the Purchaser a “Party” and, together, the “Parties”

WHEREAS:

Avanex France holds 26% of the Share Capital in Photline Technologies, a société anonyme incorporated under the laws of France, having its registered office at Rue Auguste Jouchoux, 25000 Besançon, registered with number 432 674 117 RCS Besançon.

3

These recitals forming an integral and essential part of this Agreement, the Parties agree as follows:

1. DEFINITIONS

In addition to the terms defined elsewhere in this Agreement, herein:

“Accounting Methods and Principles” means the accounting methods and principles used by the Company for the preparation of its accounts and which appear in the Annual Accounts and which are generally accepted in France;

“Agreement” means this agreement and the schedules hereto;

“Annual Accounts” means the annual accounts of the Company relating to its financial year starting on 1 July 2005 and ending on 30 June 2006;

“Assets” means the equipment, tools and tangible personal assets;

“Authorisations” means all authorisations, licences, permits, certificates, approvals or other documents delivered to the Company, by an administrative authority or any other authority or by a professional entity necessary for the Company to currently carry out its Business;

“Avanex Companies” means Avanex Corp or any other company affiliated to Avanex Corp;

“Avanex Corp Competitors” the entities listed in Exhibit 1, their affiliates and the respective successors and assigns of such entities and their affiliates; provided that in the event of a sale, assignment or transfer to a third party, pursuant to a merger, acquisition or otherwise, of all or any portion of a business or product line of an entity listed in Exhibit 1 or any of its affiliates that is in the same field as or competes with any business, product or product line of Avanex or its affiliates, such third party shall also be deemed to be an Avanex Corp Competitor. For the avoidance of doubt, such third party shall be deemed an Avanex Corp Competitor only if at least one business, product or product line of such third party or its affiliates (including without limitation any such sold, assigned or transferred business or product line, or portion thereof, of an entity listed in Exhibit 1 or any of its affiliates) is in the same field as or competes with any business, product or product line of Avanex or its affiliates.

“Beneficiary” has the meaning set forth in clause 3.18;

“Business” has the meaning set forth in the preamble;

“Borrowings” has the meaning set forth in clause 3.6;

“Cash Statement” means the statement of cash, setting out the Cash Position of the Company as at the Completion Date;

“Cash Position” has the meaning set forth in Exhibit 2;

“Completion” means the deliveries by the Seller to the Purchaser and the deliveries by the Purchaser to the Seller;

“Completion Date” means the date indicated in subclause 4.1;

4

“Control” means control within the meaning of clause L.233-3 I of the French Code of Commerce;

“Damages” has the meaning set forth in subclause 3.18;

“Disclosure” has the meaning set forth in subclause 3.17;

“Encumbrances” means any encumbrance including without limitation any floating charge, mortgage, pledge, charge, lien or assignment by way of security, option or right of pre-emption, entitlement to beneficial ownership (including usufruct and similar entitlements), and any other interest or right held by a third party.

“Employees” has the meaning set forth in subclause 3.10;

“Financing” has the meaning set forth in the preamble;

“Intellectual Property” means any or all of the following and all rights in, arising out of, or associated therewith: (i) patents, (ii) all inventions (whether patentable or not), invention disclosures, improvements, trade secrets, proprietary information, know how, technology, technical data and all documentation relating to any of the foregoing (“Know-How”), (iii) all copyrights, copyrights registrations and applications therefor, and all other rights corresponding thereto throughout the world (“Copyrights”), (iv) all industrial designs and any registrations and applications therefor throughout the world, (v) trade names, logos, common law trademarks and service marks, trademark and service mark registrations and applications therefor and all goodwill associated therewith throughout the world (“Trademarks”), (vi) all databases and data collections and all rights therein throughout the world, (vii) all moral and economic rights of authors and inventors, however denominated, throughout the world, (viii) any similar or equivalent rights to any of the foregoing anywhere in the world, and (ix) all priority rights in the foregoing, throughout the world.

“Intermediary Accounts” means the accounts of the Company as at 31 December 2006;

“Lease” has the meaning set forth in subclause 3.15;

“OIF Services Agreement” has the meaning set forth in sub-clause 4.2.5;

“Price” means the price set forth in clause 2.2 to be paid in full at the Completion Date by the Purchaser to the Seller as consideration for the Shares, in accordance with the terms and conditions of clause 2;

“Seller’s Knowledge” means the actual best knowledge of the Seller on the date of this Agreement;

“Shares” means a certain number of shares of the Company which shall correspond to 90% of the share capital and voting rights of the Company on Completion Date, to be transferred to the Purchaser pursuant to this Agreement;

“Shareholders’ Agreement” has the meaning set forth in the last paragraph of subclause 4.2.5;

“Subsidiary” shall mean, when used with respect to any Party, any corporation or other organization, whether incorporated or unincorporated, at least a majority of the securities or other interests of which having by their terms ordinary voting power to elect a majority of the Board of Directors or others performing similar functions with respect to such corporation or other organization is directly or indirectly owned or controlled by such Party or by any one or more of its Subsidiaries, or by such Party and one or more of its Subsidiaries, provided that (i) Avanex France shall not be considered a Subsidiary of Avanex, and (ii) a corporation or organization shall only be considered a Subsidiary for so long as the requisite ownership interest as set forth above exists.

5

“Target Cash Position” has the meaning set forth in subclause 4.2.3 (c);

“Taxation” means all forms of taxation, duties, levies, imposts and charges, including, without limitation, corporate income tax, wage withholding tax, value added tax, customs and excise duties, capital tax and other legal transaction taxes, dividend withholding tax, (municipal) real estate taxes, real estate transfer tax, other municipal taxes and duties, environmental taxes and duties and any other type of taxes or duties in any relevant jurisdiction, but excluding national security contributions and employee social security contributions; together with any interest, penalties, surcharges or fines relating thereto, due, payable, levied, imposed upon or claimed to be owed in any relevant jurisdiction;

“Transition of Services Agreement” has the meaning set forth in subclause 4.2.5;

“Representation and Warranties” means the representations and warranties of the Seller referred to in clause 3;

2. SALE AND PURCHASE OF THE SHARES

Subject to the closing conditions set forth in clause 4.2, the Seller undertakes to sell the full title to the Shares to the Purchaser, and the Purchaser undertakes to purchase the full title to the Shares from the Seller against payment by the Purchaser to the Seller of the Price.

The Shares shall be transferred by the Seller to the Purchaser and purchased by the Purchaser from the Seller for the Price, corresponding to EUR 1 (one) for all the Shares.

3. REPRESENTATIONS AND WARRANTIES OF THE SELLER

The Seller grants to the Purchaser the following Representations and Warranties at the Completion Date, subject to the Disclosures, as defined in clause 3.17:

The Seller is a corporation duly incorporated and organized and validly existing under the laws of the State of Delaware.

The Seller has obtained all corporate authorizations and all other applicable governmental, statutory, regulatory or other consents, licences, waivers or exemptions from a third party required to empower it to enter into and to perform its obligations under the Agreement.

This Agreement will, when executed by all Parties, constitute a legal, valid and binding obligation of the Seller enforceable against it in accordance with its terms.

The entering into this Agreement, and the performance of the obligations contemplated herein, by the Seller do not: (i) violate or conflict with any provision of the Seller’s certificate of incorporation or by-laws or the resolutions of the board of directors or stockholders of the Seller or (ii) violate or conflict with any law, regulation, order, injunction or judgment applicable to the Seller.

The Seller is not subject to any pending claim, proceeding or investigation which may delay or prevent the consummation of the transaction contemplated hereby.

The Seller has full title, and full power and authority to sell, transfer and deliver the Shares in accordance with this Agreement.

6

The Company is a corporation duly incorporated and organized and validly existing under the laws of France. It has all necessary corporate power and authority to own its property and assets and to carry on the Business.

As per the date of this Agreement, the copy of the Company’s by-laws and certificate of registration (“extrait k-bis”) attached hereto as Schedule 3.2 are up to date and accurate.

The Company has full and unrestricted ownership and possession of its business (“Fonds de Commerce”).

The Company holds all Authorisations necessary for carrying out its current activities at the date hereof.

No governmental, statutory, regulatory or other consents, licences, waivers or exemptions is required to be made by the Company prior to, or as a condition of, the execution and delivery of the Agreement.

This Agreement will, when executed, constitute a legal, valid and binding obligation of the Seller enforceable against it in accordance with its terms.

The entering into this Agreement, and the performance of the obligations contemplated herein, by the Seller do not: (i) violate or conflict with any provision of the Company’s certificate of incorporation or by-laws or the resolutions of the board of directors or stockholders of the Company or (ii) violate or conflict with any law, regulation, order, injunction or judgment applicable to the Company.

Save as set forth in Schedule 3.2, the Company is not unable to pay its accrued liabilities with its quick assets (cessation des paiements), is not subject to a judicial reorganisation or rescheduling of their indebtedness, a judicial liquidation or any measures or proceedings concerning the prevention of business bankruptcies and amicable settlements (“prévention et règlement amiable des difficultés des entreprises”) and has not made any filing in order to initiate such a proceeding.

All the shares comprising the share capital of the Company have been duly and properly issued and are fully paid up.

As at the date hereof, the Company’s issued share capital amounts is equal to EUR 15,000,000, divided into 7,500,000 ordinary shares of a nominal value of EUR 2 each, owned by the persons listed in Schedule 3.3. As at the date hereof and upon Completion, the issued and outstanding shares of the Company have been and shall be duly and validly issued, fully paid-up and non-assessable.

There are no shareholders’ agreements relating to the shareholding of the Company and, save as set forth in Schedule 3.3, the Shares are free of any Encumbrance, pledge, option, or other third party rights of any kind.

The Company has not issued securities entitling their holders to subscribe or acquire shares, warrants or other rights relating to the capital of the Company. With the exception of this Agreement and save as set forth in Schedule 3.3, no right of any nature has been granted to any third party enabling it to acquire, at any time, rights to the capital, voting rights or profits of the Company.

Further, no authorization voted by the general shareholders’ meeting of the Company to issue securities or other rights to subscribe for shares of the Company or options for the purchase or the issuance of shares of the Company or of securities convertible into, or exchangeable or exercisable for, any shares of the Company is in effect.

7

Upon transfer of the Shares at Completion Date, the Purchaser will have legal and equitable title to all the Shares, free and clear of all Encumbrances.

The Annual Accounts which are set out in Schedule 3.4:

Save as set forth in Schedule 3.5, the Company is not bound by any off balance sheet commitments (“engagements hors bilan”).

Save as set forth in Schedule 3.6, the Company has granted no loan or advance whether to an individual person or a legal entity.

All the loans, advances and subsidies granted to the Company (hereafter the “Borrowings”) are reflected in the Annual Accounts and in the Intermediary Accounts.

Schedule 3.7 contains a list of any financial contributions (“subventions”) granted by national or supranational authorities to the Company or to Avanex Companies in relation to the development of the Business.

8

The Company has filed all necessary tax and social returns, declarations and written notices required to be filed with the relevant social and tax authorities and has supplied all information to the relevant social and tax authorities as required by law within any requisite period. Any such returns and information and notices are correct and accurate in all material respects.

The Company has duly paid all amounts due to be paid by them under the relevant social and tax laws and regulations. No late penalty in respect of these tax or social declarations is due at the Completion Date.

The Company has properly and punctually submitted to the relevant tax authorities all claims and disclaimers assumed to be made for the purposes of computing any provision or reserve for tax included in the Accounts.

No claim, action, proceedings or investigations relating to taxes or social security are pending against the Company. The Company has received no written notification from the social and tax authorities that any of these authorities intends to commence any claim, investigation, proceeding or action.

The Seller shall fully indemnify and hold harmless the Purchaser and the Company against any adverse tax consequences of the transfer or relocation of some OAX assets completed prior to the signing hereof, within the limit of EUR 300,000 and without applying the limitations set forth in clause 3.17 and in subclauses 3.18.1(a), (b) and (c). It is specified for the avoidance of doubt that the remainder of section 3.18 shall remain applicable.

9

Except as indicated in Schedule 3.12 and to the Seller’s Knowledge, there are no disputes, claims in written or actions initiated, pending or threatened between the Company on the one hand and its current or former employees, French social security institutions, French tax authorities or any third party or any authority on the other hand.

A list of all the products currently designed, developed, manufactured, assembled, imported, sold and/or licensed by the Company (the “Products”) is attached in Schedule 3.13.

To the Seller’s Knowledge, during the past 3 years, no claim, notice, demand, suit or proceedings of a civil, criminal or administrative nature has been filed by a customer or any other third party or authority before any court or government body against or involving a Product or any services related thereto (a “Product Claim”), resulting from an alleged defect in the Products or any services related thereto. To the Seller’ Knowledge, no Product Claim is threatened and no defect in the Products or the services related thereto could form the basis of any Product Claim.

Schedule 3.14 attached hereto lists each insurance policy to which the Company is a party. All applicable premiums corresponding to the period prior to the Completion Date have been paid.

The Company has granted no guarantee, security, endorsement, mortgage, lien, pledge or other charge in favour of a third party with respect to its Assets.

Upon Completion, all Assets used by the Company in the operation of the Business as it is now carried on shall be (i) owned by the Company free from any third party rights or (ii) leased pursuant to a valid lease agreement.

10

Schedule 3.15 to the Agreement contains a complete list of all the leases for premises currently used or occupied by the Company (the “Leases”). The Leases are validly executed and enforceable. To the Seller’s Knowledge, the Company has in all material respects complied with the terms and conditions of all of the Leases.

The Parties specifically agree and acknowledge that any disclosure in any of the Schedules to this Agreement (the « Disclosures ») is to be considered as a disclosure against, and shall provide an exception to or otherwise qualify, any and all Representations and Warranties made by the Seller in clause 3 of this Agreement, notwithstanding that no cross-reference thereto is made to that disclosure in other potentially relevant Schedules.

11

except in respect of a claim of which the Purchaser gives written notice to the Seller in accordance with clause 3.18.6 prior to such second anniversary.

12

13

4. COMPLETION

Completion shall take place at the offices of Watson Farley & Williams LLP, Paris located at 150 avenue des Champs Elysées, 75008 Paris at a time and date to be specified by the Parties, which shall be no later than the second business day after the satisfaction or waiver of the conditions set forth in this clause 4 (other than those that by their terms are to be satisfied or waived at the Completion), and shall be no later than 7 May 2007 (the “Completion Date”).

14

On or prior to the Completion Date, the Parties agree that:

15

The Seller and the Purchaser shall enter into a shareholders agreement in the form attached in Schedule 4.2.5(f) (the “Shareholders’ Agreement”).

16

In addition to other obligations hereunder, and any other document to be executed and exchanged pursuant to this Agreement, at the Completion Date:

the continuation to the benefit of the Company of Article 1 of such Settlement Agreement and Mutual Release and any sums owed by Alcatel to the Company according to article 1 of such Settlement Agreement and Mutual Release;

17

18

The transfer in ownership of the Shares shall take place at, and take effect from, the Completion Date.

Subject to the terms and subject to the conditions set forth herein, each of the Parties agrees to use reasonable best efforts to take, or cause to be taken, all actions, and to do, or cause to be done, and to assist and cooperate with the other Parties in doing, all things necessary, proper or advisable to consummate and make effective, in the most expeditious manner practicable, the transactions contemplated by this Agreement.

5. OBLIGATIONS AFTER THE COMPLETION DATE

Seller shall make its best efforts:

The Seller shall deliver, within 7 business days from the Completion Date, the draft Cash Statement.

The Seller undertakes that, except with the prior written consent of the Company, it will not, for a period of 24 months from the Completion Date, either directly or indirectly, solicit or entice away or endeavour to entice away from the Company, employ, or offer to employ or offer to conclude any contract for services with, any director or employee of the Company as at the Completion Date.

Reciprocally, the Purchaser undertakes that it will not and shall cause that the Company will not, except with the prior written consent of the Seller, for a period of 24 months from the Completion Date, either directly or indirectly, solicit or entice away or endeavour to entice away from any Avanex Companies, employ, or offer to employ or offer to conclude any contract for services with, any director or employee of any Avanex Companies as at the Completion Date.

19

As a limited exception, these provisions shall not apply in the event of the termination of the employment contract by the employer or in the event of termination of the director’s mandate by the competent body of the relevant company, to the extent such employee or director is not subject to, or has been released from, all applicable non-compete provisions.

The Purchaser shall allow the Seller to verify, by means of review by an independent external auditor at Seller’s cost, during a period of one (1) year from Completion Date, that the amount of EUR 7.000.000 referred to in Section 4.2.3(d) is recorded in the balance sheet of the Company in order to cover the Restructuring Costs.

The Purchaser shall cause the Company to agree in writing upon Completion Date to comply with, and to render all reasonable and necessary assistance for the Seller to comply with, all provisions of the Agreement between Alcatel and the Seller effective November 10, 2005 that have been disclosed to the Purchaser, to the extent such provisions relate to the Owned Patents.

The Purchaser shall cause the Company to draw a minimum of EUR 5,000,000 (five million euros) from the Financing within a one-year period from Completion Date or to replace it by an equity (or quasi equity) financing of the same amount, which evidence will be provided to the Seller at its request.

6. IMPLEMENTATION OF PAST RESTRUCTURING PLANS

The Company is and shall be, from time to time, required to pay certain amounts as the result of the implementation of the 2003, 2004 and 2005 restructuring plans (the “Past Restructuring Costs”). The Parties have taken into account the remaining Past Restructuring Costs upon Completion to determine the Target Cash Position. Consequently, this amount will be final and binding between the Parties with respect to the Past Restructuring Costs which will be due after Completion and the Purchaser shall not, and shall cause that the Company shall not, claim any amount with respect to any part of the Past Restructuring Costs to be paid after Completion (including in accordance with the indemnification procedure set forth in clause 3.18 of this Agreement) to the Seller.

7. CASH POSITION ADJUSTMENT

The Purchaser shall have thirty (30) days, from the delivery of the draft Cash Statement to review it and notify the Seller in writing whether or not it agrees with the same and the following provisions shall apply:

20

21

8. EXPENSES

The costs, taxes, both direct and indirect, and other duties arising under this Agreement or relating to the fulfilment of the obligations hereunder shall be due as follows:

9. CONFIDENTIALITY

10. REPRESENTATIONS OF THE PURCHASER

22

11. MISCELLANEOUS

23

Any notice required or permitted under the terms of this Agreement shall be made in writing and shall be effectively and validly made upon receipt, where made by registered letter (including by hand), or by telegram, or by fax at the moment in which a confirmation of complete successful transmission is recorded.

24

or at such other address as shall be notified by such Party to the other after the date of this Agreement in accordance with its provisions. In addition to the above addresses, or such other address as may be notified in future, the Parties shall use their domiciles as their addresses for the purposes of this Agreement, including for the purposes of notices.

The tolerance by either Party of behaviour of the other Party that is in breach of the terms herein shall not constitute a waiver of the other Party’s rights under the terms breached, or of the other Party’s right to require specific performance of all the terms and conditions of this Agreement.

12. JURISDICTION AND GOVERNING LAW

Any dispute, controversy or claim arising out of or in connection with this Agreement or the breach, termination or validity thereof shall be subject to the exclusive jurisdiction of the Commercial Court of Paris.

This Agreement shall be governed by French law.

The language of this Agreement and the transactions envisaged by it is English and all notices, demands, requests, statements, certificates or other documents or communications shall be in English unless otherwise agreed and save for certain Schedules, which are in French.

The Parties to this Agreement expressly declare that it is their express intention that this Agreement be drawn up in the English language. The Parties acknowledge that they fully understand and accept any and all provisions of this Agreement, and have been assisted in the negotiation of this Agreement by a French lawyer with working abilities in both the English and the French Language. The Purchaser hereby expressly waives any rights it may have to terminate this Agreement or have it declared void because it is not drafted in the French language.

“Les Parties au présent Contrat déclarent que leur volonté expresse est que ce Contrat soit rédigé en langue anglaise. Les Parties reconnaissent avoir totalement compris et accepté chacune des dispositions du présent Contrat, et avoir été assistées dans la négociation du présent Contrat par un avocat français ayant une bonne connaissance des langues anglaise et française. L’Acquéreur renonce expressément et de façon irrévocable à tout droit qu’il pourrait avoir, le cas échéant, de résilier le présent Contrat ou de le faire déclarer nul ou d’en demander la résolution parce que le présent Contrat n’aurait pas été rédigé en langue française.”

Executed on 28 February 2007 at Paris, in 3 original versions

25

26