Operating Segments and Geographic Information - Information on Reportable Segments (Details) $ in Millions	3 Months Ended
	Sep. 28, 2024 USD ($) segment	Sep. 30, 2023 USD ($)
Information on reportable segments
Number of broad business categories (in segment) | segment	2
Total net revenue	$ 238.2	$ 247.9
Gross profit	$ 136.1	$ 144.4
Gross margin (as a percent)	57.10%	58.20%
Operating Income (Loss)	$ 11.5	$ 16.0
Operating margin (as a percent)	4.80%	6.50%
Segment Measures
Information on reportable segments
Gross profit	$ 140.7	$ 149.0
Operating Income (Loss)	23.9	30.8
Other Items
Information on reportable segments
Total net revenue	0.0	0.0
Gross profit	(4.6)	(4.6)
Operating Income (Loss)	(12.4)	(14.8)
Network and Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	159.4	170.4
Gross profit	$ 97.1	$ 108.3
Gross margin (as a percent)	60.90%	63.60%
Operating Income (Loss)	$ (7.3)	$ 1.5
Operating margin (as a percent)	(4.60%)	0.90%
Network and Service Enablement | Network Enablement | Segment Measures
Information on reportable segments
Total net revenue	$ 141.6	$ 150.0
Gross profit	$ 86.3	$ 94.6
Gross margin (as a percent)	60.90%	63.10%
Network and Service Enablement | Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	$ 17.8	$ 20.4
Gross profit	$ 10.8	$ 13.7
Gross margin (as a percent)	60.70%	67.20%
Optical Security and Performance Products | Segment Measures
Information on reportable segments
Total net revenue	$ 78.8	$ 77.5
Gross profit	$ 43.6	$ 40.7
Gross margin (as a percent)	55.30%	52.50%
Operating Income (Loss)	$ 31.2	$ 29.3
Operating margin (as a percent)	39.60%	37.80%
Product revenue
Information on reportable segments
Total net revenue	$ 197.5	$ 205.6
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	118.7	128.1
Product revenue | Network and Service Enablement | Network Enablement | Segment Measures
Information on reportable segments
Total net revenue	112.6	120.4
Product revenue | Network and Service Enablement | Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	6.1	7.7
Product revenue | Optical Security and Performance Products | Segment Measures
Information on reportable segments
Total net revenue	78.8	77.5
Service revenue
Information on reportable segments
Total net revenue	40.7	42.3
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	40.7	42.3
Service revenue | Network and Service Enablement | Network Enablement | Segment Measures
Information on reportable segments
Total net revenue	29.0	29.6
Service revenue | Network and Service Enablement | Service Enablement | Segment Measures
Information on reportable segments
Total net revenue	11.7	12.7
Service revenue | Optical Security and Performance Products | Segment Measures
Information on reportable segments
Total net revenue	$ 0.0	$ 0.0