Fiber Optic Terminology

An MZM uses an applied electric field to vary the refractive index of the waveguide carrying a light beam. This in turn modulates the phase, amplitude, or polarization of the light and can achieve direct optical upconverstion of the modulating electronic signal into an Optical Single Side Band (OSSB) signal in the output beam for radio over fiber communications. MZMs can be dual drive (each beam is split into two, separately modulated then recombined) or single drive.

When power is transferred between modes, links, wave guides, etc., maximum efficiency is achieved when the phase differences between the incident wave and propagating wave are zero over the temperature and frequency ranges of operation. RFOptic devices have small phase differences under operating conditions.

Chromatic dispersion arises from the variation in propagation velocity with wavelength. Over distance (time), an initially sharp pulse is broadened and begins to overlap with adjacent pulses causing degraded signal quality, limiting transmission distances and capacities of long-haul fiber links.
The higher the data rate (e.g., 40 Gbit/s or 160 Gbit/s) the stronger the pulse broadening relative to lower rates (e.g., 10 Gbit/s, for example).

The most common solution to chromatic dispersion is ‘dispersion compensating fiber’ (DCF). This is a length of fiber in which the chromatic dispersion has been engineered to be the exact opposite of the dispersion in the fiber link. For more information regarding specific solutions on this, refer to this link: https://www.sciencedirect.com/topics/materials-science/dispersion-compensating-fiber.

Erbium-doped Fiber Amplification
Erbium-doped fiber amplifiers are a type of optical repeater/regenerator used to periodically boost optical signal power along the long-haul fiber length.
Working Principle
The erbium fiber is illuminated by 980 nm or 1480 nm light. This pushes the erbium into a quasi-stable intermediate state. From here, it can decay to its ground state spontaneously or – incoming light can cause it to decay by stimulated emission and simultaneous amplification of the light.

Advantages
– EDFA has high pump power utilization (>50%)
– Directly and simultaneously amplify a wide wavelength band (>80nm) in the
C-Band region (1530 – 1570nm) , with relatively flat gain.
– Flatness can be improved by gain-flattening optical filters.
– Gain in excess of 50 dB
– Low noise figure suitable for long haul applications

Drone-UAV RF Communication
RFOptic’s Drone and UAV RFoF Remote Antenna enables bi-directional RFoF support between an RF antenna used to communicate with a UAV and its controller in cases where the two are separated by varying distances and are connected via optical fiber (which does not emit RF radiation).

The uplink control signals to the antenna are sent over single-mode, optical fiber; the downlink data from the UAV are converted to RFoF and are sent over the same fiber.

This enables placing significant distance between the RF antenna that is in physical communication with a drone and the drone operator or control vehicle. Although the antenna can be targeted, the distant operator is not.

The system delivers the full 4GHz – 6GHz band commonly used by such UAV controllers, and can be customized to support other frequency ranges up to 12GHz and 18GHz

The Doppler effect is the difference between the frequency at which waves leave a source and that at which they reach an observer.

Although optical signals can be propagated over distances with limited power loss, the purity (frequency, phase) of the signals can be degraded during propagation due to thermal, mechanical, and electrical perturbations affecting the optical length of the fiber.

The spurious level of RFOptic’s Optical Delay Line is small and supports Doppler shift measurements / applications where the noises caused due to the circuit boards are cleaned by the system.

Optical switching is a method to change fiber length in progressive ODLs. The standard switching time is approximately 10 ms however special techniques can shorten this time to 100 µs and less.

In half-duplex transmission a channel is used for two-way transmission but only one direction can be used at a time.
Full duplex transmission enables simultaneous transmission in both directions.

Modules support 0.15GHz – 2.5GHz for GPS and GNSS.
Bias-T with regulated 5V and 200mA (max) feed on the RF In port powers active GPS antenna.
Load resistor on the RF Out port draws current from the GPS antenna to bypass failsafe GPS receivers.
Noise Figure: 6 dB with LNA; -169 dB/Hz MDS
Impedance: 50 Ohm / 75 Ohm
The RFoF link has excellent gain flatness with ±0.5dB gain tracking between links.
Temperature stable operation supports 0.5 dB over 100° C range.
Module power: 5VDC —12VDC.
Remote management using GUI on PC.
SW Adjustable: Noise Figure, link gain, Input P1dB, and IP3 on
Tx / Rx modules using LNA’s variable attenuators.
SW activated LNA supports RF input power below -100dBm/1MHz and 5dB Noise Figure for low signal applications.
Configurations:

• Bias-T for GPS applications
• Outdoor enclosure (unidirectional/bi-directional)
• 1U Generic enclosure (4 units)
• (1,2,3)U Removable panel enclosure (4/8/12) units

Modules support up to 2.5GHz.
RFOptic’s RF over Fiber (RFoF) modules are suitable for telecommunications, satellite, radio telescopes, distribution antennas, audio and video broadcasting, and timing synchronization.
Tx modules convert the RF to RFoF optical signal; Rx modules reconvert the RFoF optical signal back to RF. Tx/Rx units are connected by a single-mode fiber.
The Tx and Rx LNAs and variable attenuators enable customers to adjust the Noise Figure, Input P1dB, and IP3 over wide dynamic ranges. LNA can be operated using RFoF software enabling RF input power of -100 dBm/1MHz for wideband applications, low Noise Figure of 6 dB. Gain flatness between links with 0.5dB gain tracking. Temperature stable operation supports 0.5 dB over 100° C .
Module power: 5VDC —12VDC.
Local and remote SW adjustment of the RF and optical parameters including link gain, Noise Figure, P1dB, Optical power, LED indication and module information.
Configurations:

• Outdoor enclosure (unidirectional/bi-directional)
• 1U Generic enclosure (4 units)
• (1,2,3)U Removable panel enclosure (4/8/12) units

Modules support 0.5GHz – 3.0GHz
RFOptic’s RF over Fiber (RFoF) modules are suitable for telecommunications, satellite, radio telescopes, distribution antennas, audio and video broadcasting, and timing synchronization.
Tx modules convert the RF to RFoF optical signal; Rx modules reconvert the RFoF optical signal back to RF. Tx/Rx units are connected by a single-mode fiber.
The Tx and Rx LNAs and variable attenuators enable customers to adjust the Noise Figure, Input P1dB, and IP3 over wide dynamic ranges. LNA can be operated using RFoF software enabling RF input power of -100 dBm/1MHz for wideband applications, low Noise Figure of 6 dB. Gain flatness between links with 0.5dB gain tracking. Temperature stable operation supports 0.5 dB over 100° C .
Module power: 5VDC —12VDC.
Local and remote SW adjustment of the RF and optical parameters including link gain, Noise Figure, P1dB, Optical power, LED indication and module information.
Configurations:

• Standalone RFoF Tx/Rx units
• Unidirectional/Bidirectional configurations
• 19” 1U Generic enclosure (up to 8 RFoF units)
• 19” 1U Removable enclosure (up to 4 RFoF units)
• 19” 2U Removable enclosure (up to 8 RFoF units)
• 19” HD enclosure (up to 40 RFoF unidirectional units or
  20 Bidirectional terminals)
• Mini RFoF enclosure (up to 2 RFoF units)
• Small outdoor enclosure (up to 6 RFoF units)
• Large outdoor enclosure (up to 8 RFoF units)

Modules support 0.5GHz – 4.0 GHz.
RFOptic’s RF over Fiber (RFoF) modules are suitable for telecommunications, satellite, radio telescopes, distribution antennas, audio and video broadcasting, and timing synchronization.
Tx modules convert the RF to RFoF optical signal; Rx modules reconvert the RFoF optical signal back to RF. Tx/Rx units are connected by single-mode fiber.
The Tx and Rx LNAs and variable attenuators enable customers to adjust parameters such as the Noise Figure, Input P1dB, and IP3 over wide dynamic ranges. LNA can be operated using RFoF software enabling RF input power of -100 dBm/1MHz for wideband applications, low Noise Figure of 6 dB. Gain flatness between links with 0.5dB gain tracking. Temperature stable operation supports 0.5 dB over 100° C .
Module power: 5VDC —12VDC.
Local and remote SW adjustment of the RF and optical parameters including link gain, Noise Figure, P1dB, optical power, LED indication and module information.
Configurations:

• Standalone RFoF Tx/Rx units
• Unidirectional/Bidirectional configurations
• 19” 1U Generic enclosure (up to 8 RFoF units)
• 19” 1U Removable enclosure (up to 4 RFoF units)
• 19” 2U Removable enclosure (up to 8 RFoF units)
• 19” HD enclosure (up to 40 RFoF units
  20 Bidirectional terminals)
• Mini RFoF enclosure (up to 2 RFoF units)
• Small outdoor enclosure (up to 4 RFoF units)
• Large outdoor enclosure (up to 8 RFoF units)

Modules support 0.5GHz – 6.0GHz.
RFOptic’s RF over Fiber (RFoF) modules are suitable for telecommunications, satellite, radio telescopes, distribution antennas, audio and video broadcasting, and timing synchronization.
Tx modules convert the RF to RFoF optical signal; Rx modules reconvert the RFoF optical signal back to RF. Tx/Rx units are connected by a single-mode fiber.
The Tx and Rx LNAs and variable attenuators enable customers to adjust the Noise Figure, Input P1dB, and IP3 over wide dynamic ranges. LNA can be operated using RFoF software enabling RF input power of -100 dBm/1MHz for wideband applications, low Noise Figure of 6 dB. Gain flatness between links with 0.5dB gain tracking. Temperature stable operation supports 0.5 dB over 100° C .
Module power: 5VDC —12VDC.
Local and remote SW adjustment of the RF and optical parameters including link gain, Noise Figure, P1dB, Optical power, LED indication and module information.
Configurations:

• Standalone RFoF Tx/Rx units
• Unidirectional/Bidirectional configurations
• 19” 1U Generic enclosure (up to 8 RFoF units)
• 19” 1U Removable enclosure (up to 4 RFoF units)
• 19” 2U Removable enclosure (up to 8 RFoF units)
• 19” HD enclosure (up to 40 RFoF units
  20 Bidirectional terminals)
• Mini RFoF enclosure (up to 2 RFoF units)
• Small outdoor enclosure (up to 4 RFoF units)
• Large outdoor enclosure (up to 8 RFoF units)”

Fifth generation cell phone technologies are the latest generation of cellular technologies currently being deployed by carriers around the world. 5G enables faster data transfer than earlier generations, better responsiveness (lower latency), and the ability to simultaneously connect more devices ( sensors and smart devices).
5G deployment began in 2019.

RFOptic offers several end-to-end solutions for 5G testing, which address the challenges of complex routing, distances, and wide bandwidth that are needed for 5G deployments. The 5G testing solutions reduce OPEX dramatically by providing software configurable RFoF terminals.
All monitoring and configuration are done via RFOptic’s HTML Monitor & Control system typically, using the REST protocol.

Testing solutions include an Optical Delay Line and RADAR Altimeter Test, radiation testing, and cable replacement due to EMC challenges using optical RF.
The RADAR Altimeter Test provides a high-performance solution for testing and calibrating RADAR Altimeter systems. It enables users to replicate the landing and taking off with real-time accuracy for pilot training. This customized Optical Delay Line solution with high-resolution delay steps “tricks” a flight simulator’s altimeter into thinking it is flying, including taking off and landing scenarios.
The radiation testing solution enables radiation testing on airplanes. Our optical RF measuring solution enables test engineers to perform these tests using a compact portable link and a chargeable battery.

“Attenuation is the reduction in (optical) signal strength between two points in the system. It is defined as the ratio of the powers at those two points. For optical fiber, the power being compared are the input power and the output power and is expressed as the logarithm of that ratio in decibels (dB).
For optical fiber it is common to normalize the attenuation by the fiber length. This attenuation coefficient is expressed in dB/unit length, typically kilometers (km).
Power loss as function of attenuation:
Attenuation . Loss
10.0 dB ……………… 90%
3.0 dB ……………… 50%
0.1 dB ………………. 2%”

The rate of optical power loss with respect to fiber length, usually measured in decibels per kilometer (dB/km at a specific wavelength. Lower numbers mean less loss. In optical fibers, typical single-mode wavelengths are 1310 and 1550 nm; typical multimode wavelengths are 850 and 1300 nanometers (nm).

RFOptic’s RFoF (RF over Fiber) transceiver is comprised of a 2-way (bidirectional) Tx and Rx uplink (at 1550nm) and a Tx and Rx downlink (at 1310nm).
The transceiver employs WDM technology to use a single fiber link.
The transceivers support 0.05 – 2.5GHz, 3GHz, 4GHz, and 6GHz.
The RFoF software enables adjustment of the RF and Optical
parameters, such as: link gain, noise figure, P1dB, optical power, LED indication and module information (locally or remotely).
In addition, the RFoF link has full diagnostic capability, including Tx, Rx and complete link test (optical and RF).
For applications that require temperature stable operation, a unique algorithm supporting 0.5 dB over -200C to +70C may be activated.
The RFoF links operate on DC power from 5 – 12 volts.

Optical fiber cable with connectors installed on one or both ends. Cable assemblies are used to connect optical fiber to optical and opto-electronic equipment.
Pigtails describes fiber with connectors attached to only one end of a cable.
Jumper or patch cord describes fiber with connectors attached to both ends of a cable.

The dielectric material surrounding the optical fiber core. It generally has a lower index of refraction than the core.