Table 1.

Transmittance for the input/output port combinations measured at a wavelength of 1531 nm [49].

	Transmittance measured at output (dB)
Input	Port 1	Port 2	Port 3	Port 4
Port 1	–	−28.4	–	−34.5
Port 2	−43.7	–	−28.0	–
Port 3	–	−37.3	–	−29.0
Port 4	−27.8	–	−42.1	–