‘Sugar cube’ modules enable upgrade to singlemode fibre

The PLD-1315 and PLD-23XX Series manufactured by PD-LD are a transmitter-receiver in a 'sugar cube' form-factor. The series is an ideal cost-effective fibre-optic communication solution for 150Mb/s over short and long range. The sugar cube form-factor allows designers to offer singlemode fibre performance in applications which currently use short-wavelength (850nm) components in identical form-factor packages. A link upgrade from multimode to singlemode fibre can be achieved by simply replacing the optical components on the circuit board.

The PLD-1315 transmitter consists of a 1300nm edge-emitting LED (ELED).  Such ELEDs efficiently couple their optical output into singlemode optical fibre. The drive circuit for the ELED can be the same circuitry that is used with multimode LED based components, versus laser-based emitters which require optical feedback.

The PLD-23XX receiver consists of a 75µm diameter InGaAs PIN photodiode and a transimpedance amplifier (TIA) with the option of automatic gain control (AGC). The PIN photodiode is optimised for high response in the 1300nm wavelength region and is matched with a low-noise TIA.  The optical signals are detected by the PIN and converted to an analogue voltage output with a very low input noise current contribution. The AGC feature decreases the light to voltage conversion factor when the average incident optical power is relatively high.

The receiver has a sensitivity of –36dBm at 100MHz and, with filtering, a minimum overload value of 0dBm. This dynamic range makes the pair ideal for both short- and long-range applications. A number of pin-outs are available to match other components on the market.


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