A new optical label switching system with coherently detected implicit spectral amplitude code （SAC） labels is proposed in this letter. The implicit SAC labels are recognized using a frequency-swept local light source oscillator. Intensity modulation payloads of 625 Mb/s and 1.25 Gb/s are considered. Label and payload bit error rate （BER） performances are assessed and compared by simulations. The results reveal that, at a BER value of 10-9, -32.4-dBm label received power can be obtained. In addition, 8.3-dB optical signal-to-noise ratio （OSNR） is obtained when carrying a payload of 625 Mb/s. The label BER value hardly reaches 10-9 if the payload bit rate is at 1.25 Gb/s; however, a high payload bit rate only has little influence on received payload quality at a BER value of 10-9. Finally, a payload of 1.25 Gb/s could obtain -28.2 dBm received power and 9.5-dB OSNR.
