JDSU 310B High Gain, Wideband O/E Converter

The Broadband Communications Products, Inc. Model 310 / 310 B is comprised of three distinct and independent functional blocks . The Optical Detector section performs the basic O/E operation; the Linear Amplifier provides additional wideband gain when required; and the ECL Limiting Amplifier may be used to convert an analog binary signal into standard emitter coupled logic (ECL) levels for communications or bit error ratio measurement and test purposes. These three functional blocks are described in more detail below.

The Optical Detector section accepts an input optical signal from a fiber and converts it into a high-fidelity electrical analog signal. The high conversion gain (>10,000 V/W) is more than 10 times that available in any other DC-coupled O/E instrument with 2 GHz bandwidth. The con-version gain is adjustable via a precision vernier 10-turn panel control. The DC reference level is also front panel adjustable around true zero, to make exact alignment with reference oscilloscope gridlines more convenient. Excessive optical input power is indicated by an overload LED, and internal protection is also activated to minimize the possibility of detector damage.

The Linear Amplifier provides 20 dB of AC-coupled gain in the 0.1-1500 MHz band. When detecting very weak signals (less than 1 microwatt), it is useful to have a convenient amplifier to aid high-level oscilloscope viewing. The amplifier can also be used as a general purpose RF gain block, for independent applications (e.g., as a scope probe amplifier).

The ECL Limiting Amplifier (ECLLA) is a unique feature of the Model 310B, which is not found on any other type of O/E converter. O/E instrument users often encounter a need to perform bit error rate tests on optical sources or use their O/E instruments as substitute receivers in communications experiments. The ECL Limiting Amplifier makes it possible to interface with standard ECL inputs on BER test sets, or drive any ECL interface with the optical signal recovered by the Model 310B Detector section. When the ECLLA is enabled via its front panel switch, and an input is applied (from the Detector or Linear Amplifier output), an internal automatic gain control function takes over, thus freeing the user from having to set detector gain levels for optimum ECL operation. Bit error ratio performance of better than 10-9 can be achieved at 1.5Gbps with optical input levels less than a -33dBm.

BCP was acquired by JDSU in 1998.