Bookham Debuts 20 Gbps Optical Transmitter Using DQPSK

Bookham Technologies described a new design of 20 Gbps optical transmitter with high tolerance to chromatic and polarization-mode distortion and with improved spectral efficiency. The company said the transmitter can double the operating distance on uncompensated SMF28 fiber compared with on/off keying (OOK) at the same bit rate. The new device leverages a new technique of differential quadrature phase-shift keying (DQPSK) and Bookham's GaAS technology. The transmitters can operate at 20 Gbps, providing parallel transmission of two SONET OC-192 data streams on a single optical channel. Bookham said this allows the potential to increase capacity while maintaining a standard 10 Gbps interface. The technology could be used for increasing the capacity of installed, long-haul, point-to-point transmission systems using expensive dispersion managed fiber.
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