Oclaro intros 100-Gbps coherent receivers

Oclaro Inc. (NASDAQ: OCLR) has expanded its 100-Gbps coherent product portfolio with the introduction of the CR5100 series of 100-Gbps coherent receivers. The new receivers are directed at implementation of polarization-multiplexed quadrature phase-shift keying (PM-QPSK, also referred to as DP-QPSK, for dual-polarization QPSK) modulation with coherent detection.

The new CR5100 series, as well as the CR5040 Series for 40-Gbps PM-QPSK applications, is designed to be compliant with the OIF Implementation Agreement OIF-DPC-RX-01.0. Oclaro has leveraged its InP integration capabilities to produce a receiver that it says offers “a significantly reduced” form factor. The process implements the optical hybrid phase mixers with integrated waveguide photodetectors. Oclaro then couples the electrical outputs of the balanced waveguide photodetectors to a pair of dual-input linear transimpedance amplifiers (TIAs). Electrical control features such as bandwidth control and manual gain adjustment optimize the TIAs’ performance. The 32-GBaud output from the receiver is then coupled to the input of the subsequent ADC/DSP IC.

The resultant form factor is so small, in fact, that Oclaro has had to add an adapter board to increase its footprint to the OIF specifications, according to Robert Blum, who runs product marketing for Oclaro’s Photonic Components business unit. Without the adapter board, the receiver’s footprint is less than half the size of what is required by the OIF.

The CR5100 series of 100-Gbps coherent receivers is sampling to tier-one systems and module manufacturers. Blum would not comment on whether Oclaro has already earned design wins, but pointed to the fact that the company plans to release the receivers for production later this year as an indication of the receivers’ popularity.

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