Fig. 1. Scheme for a two-channel SCBHD with a transmittance measuring sample inserted.

Fig. 2. Schematic of the transmittance measurement with different system errors.

Fig. 3. Transmittance spectrum of the K9 glass sample measured using a commercial photometer.

Fig. 4. Calculated misalignment error coefficient Δβn for the detected heterodyne signals.

Fig. 5. Detected heterodyne signal IB−sin and its calibrated values.

Fig. 6. Transmittance measured via OBHD, SCBHD, and direct detection.