High-quality photonic sampling streams from a semiconductor diode ring laser

Stabilization of the Absolute Frequency and Phase of a Compact, Low Jitter Modelocked Semiconductor Diode Laser

“…3 (b) shows that a near uniform 10 dB reduction of noise up to 50 KHz is obtained, with a small increase in noise around 200 KHz. This type of noise reduction at low offset frequencies and over shooting at high offset frequencies has been observed by many other researchers [10,11]. Our simple modeling suggests that this phenomenon occurs at a frequency near the band edge of the electronics used in the PLL, when the bandwidth of the electronics is wider than the bandwidth of the PLL, which is limited by the latency of a control signal from an impulse of noise.…”

“…In order to reduce the residual phase noise further, a second phase-lock loop (PLL) was added. Using the phase detector output as an error signal, another PID control circuit controls a microwave phase shifter located between the RF synthesizer and the electro-optic amplitude modulator [10]. Fig.…”

Semiconductor mode-locked lasers as pulse sources for high bit rate data transmission

“…For example, a 100-Gbit/s OTDM system with a demultiplexer that has a 5-ps switching window should have a signal source with better than 0.42 ps rms timing jitter [11]. 5. Low amplitude noise.…”

“…For ultimate flexibility in the design of the cavity elements, semiconductor ring lasers have been used [5]. These lasers are typically several meters long since they incorporate bulk devices such as a semiconductor optical amplifier (SOA), Faraday isolator, polarization controllers, and electro-optic modulator (see Fig.…”

“…Recent advances in semiconductor processing and cavity design have led to the advent of ultra-stable [3] and ultralow-noise [4,5] performance. With proper temperature control of the semiconductor device and a clean electric supply for the bias and injection current, the diode can remain mode-locked for days.…”