Harness the Power of Rugged Fiber Optics Plus Chiclet-Based Optical Transceivers

What you’ll learn:

Difference between rugged fiber optics and chiclet-based optical transceiver technologies.
How a modular approach strengthens the versatility and upgradability of RFO systems.
Preview of the CBOT future extension options in progress.

A unique synergy between rugged fiber optics (RFO) and innovative optical transceiver technologies plays a pivotal role in meeting the stringent demands of commercial and military aircraft, defense systems, and space satellites and launcher applications.

When combined with optical flex circuits, RFO cable assemblies and interconnect systems can fit more easily into limited footprints to optimize the use of available space. It also reduces the complexity of system design, integration, and maintenance in aerospace and defense applications. For example, unlike traditional electrical systems, RFO offers a lightweight alternative that significantly reduces the overall weight of the systems.

As the name suggests, rugged fiber optics are designed with the durability and resilience to withstand harsh environments, such as extreme temperature highs and lows, intense vibration and shock, and electromagnetic interference (EMI).

Optical-Electrical Conversion Requirements

While RFOs are highly efficient for data transmission, many applications require interfacing with systems that operate on electrical signals, such as traditional avionics or processing units. To ensure seamless communication across systems, optical signals must be able to be converted to electrical signals. Transceivers are crucial to this conversion process.

Understanding Modular Chiclet-Based Optical Transceivers

While a parallel-midboard (PMB) transceiver is a viable option for the optical-electrical conversion, a chiclet-based optical transceiver (CBOT) offers more advantages as a modular, space-saving solution.

CBOTs were first released in 2022 as a way to manage optical signals in commercial air applications. For example, server switching and video processor switching for both avionics displays and inflight entertainment systems are prime candidates for the modularity offered by CBOT. They have since been successfully introduced to more applications, such as defense systems.

CBOT Features and Specifications

Bandwidth: CBOTs support a wide range of bandwidths from 20 Mb/s to 10 Gb/s, adhering to IEEE 10G Base-SR standards.
Wavelength: Operating at a wavelength of 850 nm, these transceivers are optimized for short-range communication.
Power dissipation: With a power dissipation of less than 130 mW per transceiver at 10.3125 Gb/s, CBOTs are highly energy-efficient.
Temperature range: They can operate in temperatures ranging from −40 to +85°C, ensuring reliability in extreme conditions.
Channels: CBOTs support a wide array of fiber-optic cables and termini across one to 12 channels.
Standards testing: These transceivers have been rigorously tested to meet DO-160G, VITA 47, and MIL-883 standards, ensuring robustness and compliance.

Space Savings with CBOT

The modularity of CBOT (Fig. 1) results in significant space savings. A 3U VPX plug-in card (PIC) upgrade is a prime example of leveraging modularity to save space. By replacing four commercial-off-the-shelf (COTS) datacom style dual receivers (Rx) with eight half-height CBOT SM Rx blades, it saves nearly 70% in the printed-circuit-board (PCB) area. This puts CBOT and VITA 66.4 on the same card in a ready-to-go system.

1. TE Connectivity’s MULTIGIG RT fiber-optic CBOT is modular and rugged with 4G and 10G multimode capabilities.

Miniaturization with Light Engine Platforms

The modularity and space savings of rugged fiber optics don’t end with CBOT design. TE’s light engine platforms (LEPs) (Fig. 2) can exponentially decrease the size of a 10G transceiver. Typically a 12- × 12- × 56.5-mm component, it can be reduced to 1.5 × 2 × 1 mm.

2. Shown is a 3U VPX upgrade example of TE Connectivity’s CBOT space savings.

This miniaturization makes the powerful transceiver small enough to fit on a fingertip, allowing for integration into even the most space-constrained applications. Its size also translates to a more rugged and flexible design, making it possible to engineer the transceiver into optical links.

Modularity of the MULTIGIG RT Fiber-Optic Platform

The MULTIGIG RT fiber-optic platform (Fig. 3) strengthens the versatility and upgradability of RFO systems by designing for scalable configurations, interchangeable components, backward compatibility, and seamless integration with future components.

3. Light engine platform technology from TE Connectivity can shrink the power of a 10G transceiver to the size of a fingertip.

CBOTs (which incorporate LEP) are compatible with the MULTIGIG RT platform's wafer designs and press-fit pin terminations of the MULTIGIG RT 2 connector. CBOTs will soon be able to leverage upcoming MULTIGIG HD high-speed, press-fit PCB attachment.

One compelling advantage of the combined MULTIGIG HD and CBOT solution is that the data throughput can be dramatically scaled up even on the miniaturized footprint. The HD variation will pair with either four transmitters (Tx) or four receivers at a 56G PAM4 line speed. This is supported by the four high-speed data pairs on MULTIGIG HD wafers. That would move PMB transceivers (TRx) to the card edge at a higher density than today’s V66.5 edge-mount TRx options.

A full position module of 12 ferrules (48 fibers) is functionally equivalent to six midboard transceivers—freeing up space to package more functionality onto the processor card. Furthermore, TE Connectivity is developing a separable expanded beam interface concept at the backplane, further enhancing the versatility of these connectors.

MULTIGIG RT Parametric Options

MULTIGIG RT connectors are available in a variety of parametric options:

Data rates: 4G and 10G multimode transceiver options
Fiber types: OM3, OM4, and single-mode fiber
Pigtail designs: Single and dual
Pigtail lengths: From 100 mm to 6 m
Fiber types: Range of single-fiber and ribbon-cable constructions for both multimode and single-mode applications (M1 through M9 and S1 through S4) that can be used with CBOT pigtails
Fiber termini: Mechanical transfer (MT), expanded beam 16 (EB16), aeronautical radio incorporated 801 (ARINC 801), lucent connector (LC), DEUTSCH MC5 series, and MIL-PRF-29504
Channels: One to 12 options

CBOT Future Extensions

The opportunities available for smart, space-saving, modular design of the CBOT platform have spurred additional innovations. Engineers are currently developing several extension options, including:

Single-mode 1310-nm Tx and avalanche photodiode Rx: Enhancing the transceiver's capability for long-distance communication.
Linear modulation (RF over fiber): Integrating radio-frequency signals over fiber optics for improved data transmission
Mixed RF/digital and single-mode/multimode housing: Offering flexibility in housing different signal types and modes within a single transceiver.
Data-rate extension up to 25 Gb/s: Meeting the growing demand for higher data-transmission rates.
Diagnostic monitoring capability: Incorporating advanced monitoring features for real-time diagnostics and maintenance
Media conversion: Facilitating the conversion of video and CAN bus media types for seamless integration into existing systems.