A COHERENT PHOTONIC WAVELENGTH-DIVISION SWITCHING-SYSTEM FOR BROAD-BAND NETWORKS

A coherent photonic wavelength-division (WD) switching system, utilizing a coherent wavelength switch (λ switch), is proposed. In the proposed coherent λ switch, the tunable wavelength filter function is accomplished using coherent optical detection with a wavelength tunable local oscillator. The coherent photonic WD switching system has the following features; 1) low crosstalk switching for dense WDM signal, and 2) large line capacity capability. Design considerations show that 32 wavelength division channels can be available with a coherent λ switch. It is also shown that a broad-band metropolitan-area-net-work with over 1000 line capacity is possible, using a multistage connection in the coherent λ switches. The switching function of the coherent λ switch is demonstrated in a two-channel wavelength-synchronized switching experiment, using 8-GHz-spaced, 280-Mbit/s optical FSK signals. © 1990 IEEE