FORM OF LETTER TO TENDERING OPTION HOLDERS

Exhibit (a)(4)

[LETTERHEAD OF EMCORE CORPORATION]

October 30, 2002

Dear option holder:

On behalf of EMCORE Corporation (the "Company"), I am writing to provide you
with the results of the Company's recent offer to exchange (the "Offer") certain
outstanding options granted under the EMCORE Corporation 2000 Stock Option Plan
(as amended, the "2000 Plan") and the EMCORE Corporation 1995 Incentive and
Non-Statutory Stock Option Plan (as amended, the "1995 Plan" and, together with
the 2000 Plan, the "Plan") with an exercise price of at least $4.00 per share
(the "Options") for new options the Company will grant under the Plan (the "New
Options"). All capitalized terms used in this letter which are not defined
herein have the meanings given to those terms in the letter of transmittal (the
"Letter of Transmittal") accompanying the Company's offer to exchange dated
September 30, 2002 (the "Offer of Exchange").

The Offer expired at 5:00 p.m., New York City Time, on October 30, 2002.
Promptly following the expiration of the Offer and pursuant to the terms and
conditions of the Offer of Exchange, the Company accepted for exchange Options
tendered to it for a total of [____________] shares of Common Stock and canceled
all such Options.

The Company has accepted for exchange and canceled the number of Options
tendered by you equal to the number of Option Shares set forth on Attachment A
to this letter.

In accordance with the terms and subject to the conditions of the Offer, you
will have the right to receive New Options under the Plan for the number of
shares of Common Stock which is equal to the number of Option Shares set forth
on Attachment A, as adjusted for any stock splits, stock dividends and similar
events. Also in accordance with the terms of the Offer, the terms and conditions
of the New Options will be substantially the same as the terms and conditions of
the Options you tendered for exchange, except that the per share exercise price
of all new options will equal the closing sale price of our common stock on the
Nasdaq National Market on the date we grant the new options or on the first day
thereafter on which a selling price is made available to the public. In addition
the new options will be non-qualified options, not ISOs, regardless of whether
the options for which they are exchanged were ISOs.

Pursuant to the terms of the Offer, the Company will grant you the New Options
on a date determined by the Board of Directors, anticipated to be on or about
May 1, 2003. At that time, as described in the Offer to Exchange, you will
receive a new option agreement executed by the Company.

In accordance with the terms of the Offer, and as provided in the Plan, you must
be an employee of the Company or one of its subsidiaries from the date you
tendered options through the New


Option grant date in order to receive your New Options. If you do not remain an
employee , you will not receive a New Option or any other consideration for the
Options tendered by you and canceled by the Company.

If you have any questions about your rights in connection with the grant of New
Options, please call the Stock Option Exchange hotline at
option_exchange@emcore.com.

I thank you for your continued efforts on behalf of EMCORE.

Very truly yours,

EMCORE CORPORATION

By: /s/ Reuben F. Richards, Jr.
---------------------------
Name: Reuben F. Richards, Jr.
Title: President and CEO

Attachment

2

Attachment A


Number of Shares Tendered: