Table 1.

Performance list of conventional TOPS fabricated on different foundries

Heater type	Waveguide type	Test structure	Tuning efficiency/(mW·π–1)	Heating time/μs	Cooling time/μs	Foundry	References
TiN	Single strip WG	MZI	19.12	5.90	8.97	CUMEC	[49]
Silicide	Single strip WG	MZI	21.75	12.90	4.0	CUMEC	[49]
Doped silicon	Single strip WG	MZI	21.96	12.80	2.60	CUMEC	[49]
Tungsten	Single strip WG	MZI	23.4	38.2	45.11	IMEC	[50]
Silicide	Single strip WG	MZI	22.5	19.1	75.8	IMEC	[50]
Doped silicon	Single strip WG	MZI	20.4	21.3	66.0	IMEC	[50]
TiN	Single strip WG	MZI	21.4	5.6	NR	AMF	[15]
Silicide	Single rib WG	MZI	20	2.8	2.2	IBM	[16]
Doped silicon	Single rib WG	MZI	24.77 ± 0.43	NR	NR	OpSIS	[51]

TiN: titanium nitride, WG: waveguide, NR: not reported, MZI: Mach–Zehnder interferometer