(15) EARNINGS (LOSS) PER SHARE CALCULATION

The following table (in thousands except per share amounts) is a reconciliation of the numerator and denominator of the basic net income (loss) per common share (“Basic EPS”) and the diluted net income (loss) per potential common share (“Diluted EPS”). Basic EPS is computed using the weighted average number of common shares outstanding. Diluted EPS is computed using the weighted average number of (i) common shares outstanding, (ii) shares issuable upon vesting of restricted stock units, (iii) shares issuable upon exercise of outstanding stock options, employee stock purchase plan options and warrants using the treasury stock method; and (iv) shares underlying Ciena’s outstanding convertible notes.


Numerator	Quarter Ended April 30,						Six Months Ended April 30,
	2010			2011			2010			2011
Net loss	$	(90,009	)	$	(62,686	)	$	(143,342	)	$	(141,742	)


Denominator	Quarter Ended April 30,				Six Months Ended April 30,
	2010		2011		2010		2011
Basic weighted average shares outstanding		92,614		95,360		92,590		94,928

Dilutive weighted average shares outstanding		92,614		95,360		92,590		94,928


EPS	Quarter Ended April 30,						Six Months Ended April 30,
	2010			2011			2010			2011
Basic EPS	$	(0.97	)	$	(0.66	)	$	(1.55	)	$	(1.49	)

Diluted EPS	$	(0.97	)	$	(0.66	)	$	(1.55	)	$	(1.49	)

The following table summarizes the weighted average shares excluded from the calculation of the denominator for Basic and Diluted EPS due to their anti-dilutive effect for the fiscal years indicated (in thousands):


	Quarter Ended April 30,				Six Months Ended April 30,
	2010		2011		2010		2011
Shares underlying stock options, restricted stock units and warrants		2,082		6,657		1,864		6,658
0.25% Convertible Senior Notes due May 1, 2013		7,539		5,470		7,539		5,470
4.00% Convertible Senior Notes due March 15, 2015		9,607		18,396		4,777		18,396
0.875% Convertible Senior Notes due June 15, 2017		13,108		13,108		13,108		13,108
3.75% Convertible Senior Notes due October 15, 2018		—		17,356		—		17,356

Total excluded due to anti-dilutive effect		32,336		60,987		27,288		60,988