A key challenge in transceiver and digital signal processing (DSP) testing is generating significant levels of chromatic dispersion. While transmission fiber is the most intuitive solution, is it the most efficient in terms of cost, space, and performance? A Cost-Effective, High-Performance Alternative indie’s Chromatic Dispersion Emulator (CDE) is a fixed, entirely passive solution that replicates the effects of thousands of kilometers of fiber transmission. Built on indie’s proven fiber Bragg…
Narrow-Linewidth DFB Laser Diode with Unique Modulation ResponseEdge-emitting distributed feedback laser (DFB) diodes are small-sized laser sources that can be produced in high volumes at a low cost. They are widely deployed in telecommunication systems and have proven to be reliable over years of continuous operation. DFB diodes typically exhibit high levels of spontaneous emission resulting in frequency noise that may negatively affect the performance of some applications. Commercially available…
What Does “Discrete Variables” Refer To? Discrete variables (DV) refers to quantities that can be counted based on specific and indivisible observations, in opposition to continuous variables (CV) that can take any value with a range. In the context of QKD, DV protocols are associated to weak/attenuated pulses and single-photon detectors, while CV protocols use squeezed or coherent states with homodyne receivers. Where Is the “Quantum” in DV-QKD? For quantum information,…
In the realm of distributed acoustic sensing (DAS), where valuable data is extracted from the faint signals backscattered by optical fibers, technological advancements continue to push the boundaries of what’s possible. The use of narrow linewidth lasers has proven to be instrumental in enhancing spatial resolution, extending sensing distances, and expanding the frequency range of DAS systems. Narrow linewidth lasers offer precise and stable wavelength output, making them indispensable components…
Overcoming QKD Engineering Challenges Quantum Key Distribution (QKD) in quantum communications is a secure communication method that enables two parties to produce shared secret keys used afterward to encrypt and decrypt messages. Based on the principles of quantum mechanics, the process of measuring a quantum system introduces detectable anomalies, allowing for the detection of an eavesdropper. As the government, banking, medical, and other regulated industries work through digital transformation, QKD…
Fiber Bragg gratings can be used to obtain different wavelength reflectivity profiles that depend on the refractive index pattern that is inscribed in the fiber. By relying on proven in-house design and simulation tools and state-of-the-art grating inscription methods, unique ultra-narrowband fiber-based optical filters can be realized. In addition to a bandwidth (BW) that can be as narrow as 2 GHz or 50 MHz, depending on the type of filter, fiber Bragg…
For dense wavelength-division multiplexing DWDM links up to 80 km, 100G PAM4 QSFP28 transceivers offer reduced cost, lower power consumption, and smaller footprint than conventional coherent transceivers, but at the cost of having to accurately manage chromatic dispersion (CD). Far from a showstopper, we will see that compensating CD in PAM4 links is quite simple and demonstrate this by drawing a few examples. When transmitted beyond a few kilometers, 100G…
