Operating Segments and Geographic Information - Information on Reportable Segments (Details) $ in Millions	3 Months Ended	6 Months Ended
Dec. 28, 2019 USD ($)	Dec. 29, 2018 USD ($)	Dec. 28, 2019 USD ($) segment	Dec. 29, 2018 USD ($)
Information on reportable segments
Number of broad business categories (in segment) \| segment			2
Total net revenue	$ 313.7	$ 306.9	$ 613.5	$ 575.4
Gross profit	$ 189.5	$ 178.0	$ 363.9	$ 328.4
Gross margin (as a percent)	60.40%	58.00%	59.30%	57.10%
Operating income	$ 45.0	$ 32.9	$ 65.7	$ 31.7
Operating margin (as a percent)	14.30%	10.70%	10.70%	5.50%
Segment Measures
Information on reportable segments
Total net revenue			$ 613.5	$ 575.4
Gross profit			$ 383.1	$ 348.4
Gross margin (as a percent)			62.40%	60.50%
Operating income			$ 120.6	$ 107.7
Operating margin (as a percent)			19.70%	18.70%
Other Items
Information on reportable segments
Total net revenue	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Gross profit	(9.7)	(9.8)	(19.2)	(20.0)
Operating income	(22.9)	(31.0)	(54.9)	(76.0)
Network and Service Enablement \| Segment Measures
Information on reportable segments
Total net revenue	234.2	223.7	454.0	414.4
Gross profit	$ 155.6	$ 146.0	$ 296.2	$ 267.2
Gross margin (as a percent)	66.40%	65.30%	65.20%	64.50%
Operating income	$ 37.5	$ 32.8	$ 59.8	$ 49.2
Operating margin (as a percent)	16.00%	14.70%	13.20%	11.90%
Network and Service Enablement \| Network Enablement \| Segment Measures
Information on reportable segments
Total net revenue	$ 203.0	$ 195.5	$ 401.9	$ 360.0
Gross profit	$ 134.8	$ 125.7	$ 262.8	$ 228.6
Gross margin (as a percent)	66.40%	64.30%	65.40%	63.50%
Network and Service Enablement \| Service Enablement \| Segment Measures
Information on reportable segments
Total net revenue	$ 31.2	$ 28.2	$ 52.1	$ 54.4
Gross profit	$ 20.8	$ 20.3	$ 33.4	$ 38.6
Gross margin (as a percent)	66.70%	72.00%	64.10%	71.00%
Optical Security and Performance Products \| Segment Measures
Information on reportable segments
Total net revenue	$ 79.5	$ 83.2	$ 159.5	$ 161.0
Gross profit	$ 43.6	$ 41.8	$ 86.9	$ 81.2
Gross margin (as a percent)	54.80%	50.20%	54.50%	50.40%
Operating income	$ 30.4	$ 31.1	$ 60.8	$ 58.5
Operating margin (as a percent)	38.20%	37.40%	38.10%	36.30%
Product revenue
Information on reportable segments
Total net revenue	$ 281.9	$ 272.8	$ 546.7	$ 513.9
Product revenue \| Other Items
Information on reportable segments
Total net revenue	0.0	0.0	0.0	0.0
Product revenue \| Network and Service Enablement \| Segment Measures
Information on reportable segments
Total net revenue	202.5	189.8	387.5	353.3
Product revenue \| Network and Service Enablement \| Network Enablement \| Segment Measures
Information on reportable segments
Total net revenue	183.9	176.0	361.2	325.9
Product revenue \| Network and Service Enablement \| Service Enablement \| Segment Measures
Information on reportable segments
Total net revenue	18.6	13.8	26.3	27.4
Product revenue \| Optical Security and Performance Products \| Segment Measures
Information on reportable segments
Total net revenue	79.4	83.0	159.2	160.6
Service revenue
Information on reportable segments
Total net revenue	31.8	34.1	66.8	61.5
Service revenue \| Other Items
Information on reportable segments
Total net revenue	0.0	0.0	0.0	0.0
Service revenue \| Network and Service Enablement \| Segment Measures
Information on reportable segments
Total net revenue	31.7	33.9	66.5	61.1
Service revenue \| Network and Service Enablement \| Network Enablement \| Segment Measures
Information on reportable segments
Total net revenue	19.1	19.5	40.7	34.1
Service revenue \| Network and Service Enablement \| Service Enablement \| Segment Measures
Information on reportable segments
Total net revenue	12.6	14.4	25.8	27.0
Service revenue \| Optical Security and Performance Products \| Segment Measures
Information on reportable segments
Total net revenue	$ 0.1	$ 0.2	$ 0.3	$ 0.4

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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