Table 2 Peak CE and 1 dB bandwidth comparison of CGA optimized gratings for combinations of different SiN slab thickness and claddings.

From: High efficiency DBR assisted grating chirp generators for silicon nitride fiber-chip coupling

tSiN (nm)

Air cladding

SiO2 cladding

Peak Coupling (dB)

Bandwidth-δλ1dB (nm)

Peak Coupling (dB)

Bandwidth-δλ1dB (nm)

Si sub

2 DBR

4 DBR

Si sub

2 DBR

4 DBR

Si sub

2 DBR

4 DBR

Si sub

2 DBR

4 DBR

300

−3.4

−0.66

−0.56

27

35

36

−3.0

−0.56

−0.48

32

44

45

40

−2.2

−0.56

−0.5

33

39

40

−2.5

−0.38

−0.31

35

42

43

500

−1.47

−0.5

−0.46

31

33

33

−2.4

−0.33

−0.26

33

43

43

600

−1.2

−0.5

−0.48

24

26

26

−3.13

−0.36

−0.28

26

38

39

700

−1.65

−0.5

−0.46

22

23

23

−2.8

−0.46

−0.36

20

30

30

  1. The figures are provided for 3 cases which are gratings with a bare Si substrate at optimal BOX height (Si sub), and those with a 2 and 4 layer DBR stack.
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