Optical communications systems are highly regarded for their generous bandwidths and capabilities of transferring massive amounts of data during extremely short transmission times. Of course, those systems rely on durable, high-performance components connected by single-mode (SM) and multi-mode (MM) cables, which must be checked and maintained at regular intervals. That can be done using fiber-optic test equipment designed specifically for the task: optical spectrum analyzers and optical waveform generators.
This blog will focus on selecting an optical spectrum analyzer, while a future blog will offer advice on understanding the specifications for selecting an optimum precision optical test source. An optical spectrum analyzer is essentially a receiver that can detect and displaying signal waveforms within a designated wavelength range. Matching an optical analyzer to a measurement requires some basic understanding of the key performance parameters of a modern optical spectrum analyzer, since different optical wavelengths and bandwidths are used in high-speed optical communications systems and other optical applications. The optical analyzer of choice should meet or exceed the span of optical wavelengths required by system to be tested or a device under test (DUT), such as 600 to 1700 nm (which is also designated as 0.6 to 1.7 µm) which is suitable for testing most optical communications networks and components.
Key Optical Analyzer Specs
As with a spectrum analyzer designed for measuring electromagnetic (EM) energy, an optical spectrum analyzer can be evaluated in terms of many key performance parameters, including its dynamic range, which is the difference between the largest and the lowest-level optical signals that it can detect and display with an acceptable amount of accuracy. The lower end of the dynamic range is set by an analyzer’s optical sensitivity, which is the lowest-level signal that it can detect and display. The higher end is set by the maximum optical level that an analyzer can read without excessive distortion. The dynamic range can be boosted at the higher end using optical attenuators, either integrated as part of the design of the analyzer for automatic use or added to the output of a DUT as an external attenuator (operating over the wavelength to be measured) prior to the input port of the optical spectrum analyzer, to reduce test signals to acceptable levels for an analyzer.
As with RF/microwave spectrum analyzers, the cost of an optical spectrum analyzer will increase with its capabilities and performance, with the need for high optical accuracy over a wide dynamic range, for example, bearing with it a relatively high price tag and being dictated by the measurement requirements of a particular application or set of applications, such as characterizing the output levels of optical components based on laser diodes (LDs) or light-emitting-diode (LED) semiconductor devices or the precision of distributed feedback laser diode (DFB-LD) components for optical communications systems or equipment.
For a given dynamic range, for example, 60 or 70 dB, an optical spectrum analyzer will be characterized in terms of its wavelength resolution, or how small a portion of a wavelength it can clearly display, such as within ±1 nm or finer, at ±0.1 nm, and the amplitude flatness of the displayed waveform, such as ±1 dB or finer, at ±0.1 dB. Its optical response will also be characterized in terms of its linearity, with a typical response provided within an amplitude window, such as ±0.1 or ±0.5 dB, which is expected to be the worst-case variations in amplitude for all optical measurements ...
Get Exactly What You Need. Rent - Buy - Repair - Trade-In
Established in 2005, Axiom Test Equipment strives to continually improve itself and offer the best value for its customers. We offer our customers several practical, efficient and cost effective solutions for their business or projects' test equipment needs. Whether you need to rent & buy test equipment, repair test equipment, sell or trade equipment, we are committed to providing superior customer service and high quality electronic test equipment.
At Axiom Test Equipment we provide several services. We rent electronic test and measurement equipment. We also sell test equipment. If you have a piece of malfunctioning or broken test equipment we also have an in-house repair lab. For anyone seeking a way to offload their surplus or obsolete equipment, we offer a trade-in program or we can buy the equipment from you.
We stock a comprehensive inventory of equipment and can use our extensive network to find you those hard to get items. We believe in getting equipment to you quickly and at a competitive price.
Axiom Test Equipment 2610 Commerce Way Vista, CA 92081 Phone: (760) 806-6600 Web: www.axiomtest.com
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas
and reference material while performing my work as an RF system and circuit design engineer.
The Internet was still largely an unknown entity at the time and not much was available
in the form of WYSIWYG
All trademarks, copyrights, patents, and other rights of ownership to images and text
used on the RF Cafe website are hereby acknowledged.