SBIR-STTR Award

Fiber optic networks, particularly those which operate at 1300 nm, have been in widespread use since the 1980s. Standards for the transmission of NRZ data at rates in excess of 1 Gb/s already exist or are in formulation. Among these are the SONET standards (with data rates defined through 2.5 Gb/s) and Fiber Channel (with a data rate of 1.0625 Gb/s). Gigabit data rate standards also exist in Europe and Japan. A pivotal function required by fiber optic networks is the optical to electrical converter, which receives the optical signal and extracts a clock and data from it. The performance of this building block is the key in controlling the system jitter of the communications network. Because of the need for the ultimate jitter performance, not much emphasis has been placed on the development of compact or low power solutions because of the existence of bulky but effective methods of meeting bit error rate requirements. The purpose of this research is to develop a single package (0.25" x 0.25" x 0.1") surface mounted receiver/synchronizer which incorporates the entire optical to electrical conversion function and dissipates less than 500 mW. If this research is successful, a substantial power and weight savings will result making possible the use of more complex local area networks in weight and power critical applications (such as airplanes and submarines) or the use of cheaper LED based LANs (as opposed to laser diodes) with shorter repeater distances.

Fiber optic networks, particularly those which operate at 1300 nm, have been in widesread use since the 1980s. Standards for the transmission of NRZ data at rates in excess of 1 Gb/s already exist or are in formulation. Among these are the SONET standards (with date rates defined through 1.5 Gb/s) and Fiber Channel (with a data reate of 1.0625 Gb/s). Gigabit data rate standards also exist in Europe and Japan. A pivotal function required by fiber optic networks is the optical to electrical converter, which receives the optical signal and extracts a clock and data from it. The performance of this building block is key in controlling the system jitter performance, of the communications network. Because of the need for the ultimate jitter performance, not so much emphasis has been placed on the development of compact or low power solutions because of the existence of bulky but effective methods of meeting bit error performance requirements. Having succesfully demonstrated a working clock recovery circuit based upon a new type of phase detector, TechnoConcepts intends to continue this work by integrating the clock recovery circuit with a complete transimpedance amplifier subsystem. By using an external photodiode, a complete single package (0.25" x 0.25" x 0.1") surface mounted optical receiver can be obtained. The low power dissipation, and small profile (500mW) combine to make this an optimum technology for use in multiple node local area network applications. Additionally MSM photodiode technology may be used to create a completely monolithic solution at shorter wavelengths.

Keywords:
GAAS OPTICAL RECEIVER CLOCK RECOVERY FIBER OPTIC NEETWORKS