Operating Segments and Geographic Information - Information on Reportable Segments (Details) $ in Millions	3 Months Ended
	Sep. 30, 2023 USD ($) segment	Oct. 01, 2022 USD ($)
Information on reportable segments
Number of broad business categories (in segment) | segment	2
Total net revenue	$ 247.9	$ 310.2
Gross profit	$ 144.4	$ 184.8
Gross margin (as a percent)	58.20%	59.60%
Operating income	$ 16.0	$ 49.8
Operating margin (as a percent)	6.50%	16.10%
Segment Measures
Information on reportable segments
Gross profit	$ 149.0	$ 193.4
Operating income	30.8	67.4
Other Items
Information on reportable segments
Total net revenue	0.0	0.0
Gross profit	(4.6)	(8.6)
Operating income	(14.8)	(17.6)
Network and Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	170.4	218.9
Gross profit	$ 108.3	$ 141.6
Gross margin (as a percent)	63.60%	64.70%
Operating income	$ 1.5	$ 28.8
Operating margin (as a percent)	0.90%	13.20%
Network and Service Enablement | Network Enablement | Segment Measures
Information on reportable segments
Total net revenue	$ 150.0	$ 196.5
Gross profit	$ 94.6	$ 126.8
Gross margin (as a percent)	63.10%	64.50%
Network and Service Enablement | Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	$ 20.4	$ 22.4
Gross profit	$ 13.7	$ 14.8
Gross margin (as a percent)	67.20%	66.10%
Optical Security and Performance Products | Segment Measures
Information on reportable segments
Total net revenue	$ 77.5	$ 91.3
Gross profit	$ 40.7	$ 51.8
Gross margin (as a percent)	52.50%	56.70%
Operating income	$ 29.3	$ 38.6
Operating margin (as a percent)	37.80%	42.30%
Product revenue
Information on reportable segments
Total net revenue	$ 205.6	$ 267.7
Product revenue | Other Items
Information on reportable segments
Total net revenue	0.0	0.0
Product revenue | Network and Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	128.1	176.5
Product revenue | Network and Service Enablement | Network Enablement | Segment Measures
Information on reportable segments
Total net revenue	120.4	166.3
Product revenue | Network and Service Enablement | Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	7.7	10.2
Product revenue | Optical Security and Performance Products | Segment Measures
Information on reportable segments
Total net revenue	77.5	91.2
Service revenue
Information on reportable segments
Total net revenue	42.3	42.5
Service revenue | Other Items
Information on reportable segments
Total net revenue	0.0	0.0
Service revenue | Network and Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	42.3	42.4
Service revenue | Network and Service Enablement | Network Enablement | Segment Measures
Information on reportable segments
Total net revenue	29.6	30.2
Service revenue | Network and Service Enablement | Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	12.7	12.2
Service revenue | Optical Security and Performance Products | Segment Measures
Information on reportable segments
Total net revenue	$ 0.0	$ 0.1