Extended-Temperature Operation (−40 °C to +95 °C) of an EML TOSA Employing an Athermal Optical System

An electroabsorption-modulated laser (EML) transmitter optical sub-assembly (TOSA) employing an athermal optical system has been demonstrated for extended-temperature operation from -40 °C to 95 °C. The output power variation of the TOSA was held to <;0.3 dB over this wide temperature range because of optical compensation using the thermo-optical properties of the plastic lens. A 0.8-dB improvement over the variation without this compensation was confirmed. Since the TOSA has sufficient electrical bandwidth for 20-Gb/s operation, clear eye openings with an extinction ratio of over 9.7 dB were obtained over the wide temperature range. The heat sink, the size of which was optimized for operation of the EML at 55 °C, enabled the TOSA to operate over the wide temperature range without thermal runaway. As a result, power consumption of <;0.42 W was achieved over the temperature range.